Scopus Research — Mujtaba A. Flayyih

This study aims to improve thermal management in small, high-power devices by numerically analyzing water-cooled micro-pin-fin heat sinks with novel geometries. Under various Reynolds numbers, the impacts of the proposed fin geometry and diameter ratio were systematically assessed using computational fluid dynamics (CFD). The trade-off between cooling enhancement and hydraulic losses was evaluated by analyzing key performance indicators, including average Nusselt number, wall temperature, pressure drop, thermal energy absorption, heat transfer coefficient, and thermal performance factor. The concave pin-fin configuration (Case A) outperformed traditional cylindrical fins in the first section, improving thermal performance of almost 8 % at Re = 500 and 7 % at Re = 2000. The impact of the diameter ratio was examined in the second section. The biggest ratio (DR = 1.00) produced the best results, with efficiency gains of roughly 6 % at Re = 500 and 5 % at Re = 2000 compared to the lowest ratio (DR = 0.25). All things considered, the results demonstrate that novel pin-fin designs and adjusted diameter ratios deliver notable and reliable increases in thermal efficiency across a broad range of flow conditions, making them attractive options for cutting-edge liquid-cooling applications. © 2025 Elsevier Ltd

The authors regret that the affiliation of Dr. Abdellatif M. Sadeq was incorrectly listed in the published article as “Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, Doha, Qatar”. The correct affiliation is: Independent Researcher, Mechanical Engineering, Doha, Qatar. In addition, the email address linked to Dr. Abdellatif M. Sadeq should be updated to: [email protected]. The authors would like to apologise for any inconvenience caused. CRediT authorship contribution statement Mohammed Azeez Alomari: Writing – original draft, Supervision, Project administration, Conceptualization, Methodology. Ahmed M. Hassan: Writing – original draft, Methodology, Software, Conceptualization, Formal analysis. Abdalrahman Alajmi: Writing – review & editing, Visualization, Resources, Funding acquisition. Abdellatif M. Sadeq: Formal analysis, Funding acquisition, Writing – review & editing. Faris Alqurashi: Writing – original draft, Validation, Investigation. Mujtaba A. Flayyih: Writing – review & editing, Visualization, Validation. © 2026 The Author(s)

The authors regret that the affiliation of Dr. Abdellatif M. Sadeq was incorrectly listed in the published article as “Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, Doha, Qatar”. The correct affiliation is: Independent Researcher, Mechanical Engineering, Doha, Qatar. In addition, the email address linked to Dr. Abdellatif M. Sadeq should be updated to: [email protected]. The authors would like to apologise for any inconvenience caused. CRediT authorship contribution statement Ahmed M. Hassan: Writing – original draft, Investigation, Methodology, Conceptualization. Mohammed Azeez Alomari: Writing – original draft, Supervision, Project administration, Conceptualization, Investigation. Qusay H. Al-Salami: Writing – original draft, Validation, Investigation, Methodology. Faris Alqurashi: Investigation, Visualization, Validation, Writing – original draft. Mujtaba A. Flayyih: Visualization, Validation, Writing – review & editing, Investigation. Abdellatif M. Sadeq: Writing – review & editing, Funding acquisition, Formal analysis, Validation. © 2026

The flow of Williamson fluid over a stretched sheet serves as a model for various real-world scenarios involving the interaction of non-Newtonian fluids with moving surfaces. Its notable practical applications are in the fields of Polymer Processing, Food Processing, and Biomedical Applications. The primary goal of the proposed model is to investigate the effects of Ohmic heating and viscous dissipation on the bidirectional flow of Williamson and micropolar fluids within a porous medium over an extending surface. This study is novel in that it employs the FEM(Finite Element Method) approach to analyze the numerical values of the fluid and thermal characteristics of an incompressible convective flow over a flat surface for the first time. Another novel aspect of this work is the investigation of Arrhenius function terms and magnetic forces in moving fluid flow. Heat convection and velocity slip at the surface are also examined. The mathematical model of the problem results in higher-order, nonlinear ordinary differential equations through the appropriate combination of variables. The Finite Element Method is used to solve the given nonlinear system of differential equations. The present study has revealed several significant insights, notably that skin friction increases with the enhancement of porosity, as well as the characteristics of Williamson fluids and micropolar fluids. Flow patterns are analyzed and visualized by examining and graphing various components that result from the analysis. As the slip parameter increases, the velocity field decreases in the x-direction. As the heat transfer of the Williamson fluid flowing over the stretched sheet increases at k = 3, its velocity is approximately 45.55 % greater compared to the k = 1 case under the lowest heat transfer condition. The velocity in the x-direction decreases as the slip parameter increases. Additionally, it has been observed that the concentration of the Williamson fluid decreases, while the temperature distribution increases with higher Eckert number values. © 2025 The Author(s)

Thermal management of electronic devices represents a critical challenge in modern technology, necessitating innovative cooling solutions that can efficiently dissipate heat while maintaining system performance. This study presents a numerical investigation of hydrothermal performance and entropy generation in a circular cooling system utilizing Nano-Encapsulated Phase Change Materials (NEPCM) under the influence of magnetic fields and mixed convection. The aim is to optimize heat transfer performance while minimizing system irreversibilities through comprehensive parametric analysis of key operating conditions. The system features a rotating core and multiple integrated circuit ports. The governing equations were solved using the Galerkin weighted finite element method, with the computational domain discretized using an unstructured mesh refined near critical boundaries. The analysis encompassed various parameters: Reynolds number (10−100), Richardson number (0.1–7), Lewis number (0.1–10), buoyancy ratio (1–5), Hartmann number (5–80), NEPCM volume fraction (0.015–0.035), Stefan number (0.1–0.8), and fusion temperature (0.1–0.9). Significant outcomes demonstrate: (1) Mixed convection synergy achieving 209.8% heat transfer enhancement at Ri = 7, (2) Magnetic field providing 25% thermal control capability for adaptive cooling, (3) NEPCM phase change optimization yielding 5.2% performance improvement at θf = 0.7, and (4) Entropy analysis revealing thermal irreversibility dominance (Be >0.92) enabling system optimization. The magnetic field showed substantial control over system performance, with Ha = 80 reducing heat transfer by approximately 25%. Critical applications include high-performance processor cooling in gaming systems, electric vehicle battery thermal management, data center cooling infrastructure, and aerospace electronic systems where weight and efficiency are paramount. The study demonstrates that optimal thermal performance can be achieved through strategic control of mixed convection and magnetic field parameters, with NEPCM providing enhanced thermal management capabilities for electronic cooling applications. © 2024

The authors regret that the affiliation of Dr. Abdellatif M. Sadeq was incorrectly listed in the published article as “Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, Doha, Qatar”. The correct affiliation is: Independent Researcher, Mechanical Engineering, Doha, Qatar. In addition, the email address linked to Dr. Abdellatif M. Sadeq should be updated to: [email protected]. The authors would like to apologise for any inconvenience caused. CRediT authorship contribution statement Ahmed M. Hassan: Writing – original draft, Software, Methodology, Formal analysis, Conceptualization. Mohammed Azeez Alomari: Writing – original draft, Supervision, Conceptualization, Methodology, Project administration. Abdalrahman Alajmi: Visualization, Resources, Funding acquisition. Abdellatif M. Sadeq: Formal analysis, Funding acquisition, Writing – review & editing. Faris Alqurashi: Validation, Investigation, Writing – original draft. Mujtaba A. Flayyih: Writing – review & editing, Visualization, Validation. © 2026 The Author(s)

A numerical investigation of double-diffusive mixed convection in a magnetized dual-zone cavity containing counter-rotating cylinders and NEPCM suspension was conducted. The cavity is partitioned by a central porous separator, with imposed temperature and concentration gradients across vertical walls. The governing equations were solved using the Galerkin finite element method, with comprehensive validation against published experimental and numerical results. The parametric study encompassed Reynolds number (10−100), Richardson number (0.1–10), Hartmann number (5–80), Lewis number (0.1–10), buoyancy ratio (1–5), Stefan number (0.1–0.9), and NEPCM volume fraction (0.01–0.04). The investigation revealed three primary findings that significantly impact thermal management system design. First, combined forced-natural convection effects demonstrated exceptional enhancement potential, with heat transfer increasing by 523.7 % and mass transfer by 399.6 % at elevated Richardson numbers. (Second, magnetic field control emerged as a critical parameter, systematically reducing transport rates by up to 48.8 %, enabling precise flow regulation. Third, asymmetric cylinder rotation configurations unexpectedly outperformed symmetric arrangements, achieving 12–14 % superior performance. The magnetic field showed a suppressive effect, reducing heat and mass transfer rates by 29.6 % and 48.8 % respectively at maximum field strength. These findings establish fundamental design principles for optimizing NEPCM-based thermal management systems under electromagnetic control. © 2025 Elsevier Ltd

The authors regret that the affiliation of Dr. Abdellatif M. Sadeq was incorrectly listed in the published article as “Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, Doha, Qatar”. The correct affiliation is: Independent Researcher, Mechanical Engineering, Doha, Qatar. In addition, the email address linked to Dr. Abdellatif M. Sadeq should be updated to: [email protected]. The authors would like to apologise for any inconvenience caused. CRediT authorship contribution statement Ahmed M. Hassan: Formal analysis, Software, Writing – original draft, Conceptualization, Methodology. Mohammed Azeez Alomari: Writing – original draft, Project administration, Conceptualization, Supervision, Methodology. Abdellatif M. Sadeq: Funding acquisition, Formal analysis, Writing – review & editing. Faris Alqurashi: Visualization, Validation, Writing – original draft, Investigation. Mujtaba A. Flayyih: Visualization, Resources, Investigation, Writing – review & editing. © 2026 The Author(s)

Latent heat thermal energy storage systems using phase change materials face key challenges, particularly the low thermal conductivity of phase change materials and the limited investigation of insulating effects like air layers within storage geometries. This study numerically examines the impact of air layers on the melting behavior of paraffin wax (RT42) inside a horizontal double concentric tube using a two-dimensional computational fluid dynamics model in ANSYS/FLUENT 16. Three configurations were analyzed: no air layer, a 1 mm air layer, and a 2 mm air layer surrounding the inner heated tube. The enthalpy-porosity method was applied to simulate the melting process, accounting for heat transfer by conduction and natural convection. Results show that introducing a 1 mm air gap extended the melting time by 28.57%, while a 2 mm air gap led to a 57.14% increase, primarily due to the added thermal resistance. This is the first study to quantitatively assess air layer effects in this geometry, offering new insights into optimizing phase change material-based storage systems by considering internal insulation phenomena. © The Author(s) 2026.

The prosthetic socket is the primary component of a lower-limb prosthesis and must be replaced when the patient's stump size changes. This study aims to design an adjustable socket that can be adjusted to the required size without manufacturing a new socket. In this study, the model was developed in SolidWorks and analyzed numerically using ANSYS. A tensile and fatigue test was performed for the materials used in manufacturing the socket, as well as an F-Socket test on an amputated person to measure the interface pressure between the stump and the socket to be used as a boundary condition during the numerical analysis process. The results demonstrated key achievements: the model was designed to serve as an alternative to the traditional model, thereby reducing costs in socket manufacturing due to growth or changes in stump size. The results also indicated the feasibility of using carbon fiber filament as an alternative to polypropylene and of employing additive manufacturing instead of the currently expensive methods. © 2025, Mustansiriyah University College of Engineering.

The behavior of a non-prismatic beam under static and dynamic loads depends on the density distribution and geometry of the beam along its length. An essential type is a pre-twisting beam. In the current study, the dynamic response of a pre-twisted beam vibrated freely and forced under a harmonic force was investigated by establishing finite element modeling via ANSYS software. Beam length and twist angle were considered as pre-twist parameters. Beam length varying from 300 mm to 1000 mm and twist angle ranging from 0 to 360° with incremented 45°. Modal analysis and then harmonic response were implemented to calculate the natural frequency, total deflection and equivalent stress, and the damping ratio variation with pre-twisting beam parameters. The model was validated against previous studies, showing perfect agreement. The obtained results show that the first natural frequency increases when the twisting angle rises till (180°) and then remains constant. Notably, the influence of the beam length on the harmonic response reduces when the twisting angle is greater than 180°. Similarly, the deflection of harmonic response increases when the frequency ratio is approximately unity. Finally, the influence of the length of the beam and twisting angle on the stress appears when the twisting angle is smaller than 180°. © 2026, University of Kufa. All rights reserved.

This study numerically investigates the hydrothermal performance and entropy generation in a trapezoidal cavity filled with nano-encapsulated phase change material (NEPCM)-water mixture for electronic cooling under magnetohydrodynamic (MHD) and double-diffusive mixed convection. The governing equations were solved using the Galerkin finite element method. The novelty lies in exploring the coupled effects of MHD suppression and NEPCM thermal enhancement on integrated circuit (IC) cooling performance. Key parameters investigated include Reynolds number (Re=10−100), Richardson number (Ri=0.1−7), Lewis number (Le=0.1−10), Hartmann number (Ha=5−80), NEPCM volume fraction (ϕ=0.015−0.035), Stefan number (Ste=0.1−0.8), and fusion temperature (θf=0.1−0.9). Results reveal that heat transfer enhancement reaches 192.77% at Re=100 when Ri increases from 0.1 to 7, with Le=0.5,Nz=2,Ste=0.1,θf=0.5,ϕ=0.01, and Ha=10 held constant), while NEPCM concentration increases the average Nusselt number (Nuav) by 33.77% when ϕincreases from 0.015 to 0.035 at Re=50, Ri=1, Le=0.5,Nz=2,Ste=0.1,θ_f=0.5,andHa=10. However, magnetic field strength suppresses convection, reducing heat transfer. Mass transfer characteristics show strong Lewis number sensitivity but remain insensitive to phase change parameters. Entropy generation decreases with both NEPCM concentration and magnetic field strength. These findings provide optimization guidelines for designing energy-efficient electronic cooling systems utilizing NEPCM under magnetic field influence. © 2026 The Author(s).

This study investigates heat transfer in a square cavity filled with nano-encapsulated phase change material (NEPCM) and water, featuring a flexible oscillating fin and subjected to an inclined magnetic field. Arbitrary Lagrangian-Eulerian (ALE) was used to solve the governing equations. The study includes verifying the effect of the following parameters: Rayleigh number from 103 to 105, Hartmann number from 0 to 30, Stefan number from 0.1 to 0.9, NEPCM concentration from 0.01 to 0.04, fusion temperature from 0.1 to 0.9, oscillation amplitude from 0.05 to 0.15, magnetic field angle from 0o to 90o. The results showed that heat transfer enhanced by increasing Rayleigh number and NEPCM concentration, with Nusselt number increasing by 82.8 % as Rayleigh number rises from 104 to 105. Conversely, increasing Hartmann number suppresses convection, reducing Nusselt by 17 % as Hartmann increases from 5 to 30. An optimal fusion temperature of θf ≈ 0.5 maximizes heat transfer efficiency. The flexible fin's oscillation amplitude modestly improves heat transfer, while the magnetic field's inclination angle exhibits a non-linear effect with an optimal angle around 45°. These results offer guidance on how to best optimise NEPCM-based thermal management systems for a range of applications. © 2024 The Authors

The current work extensively investigates double-diffusive of nano-encapsulated phase change material in a thermal storage system partially filled with porous foam. The generation of irreversibilities and the influence of Soret/Dufour and magnetohydrodynamic effects are also considered. The circular cold cavity contains a corrugated hot cylinder covered by an annular foam. The considered parameters are Rayleigh number (103–105), fusion temperature (0.1–0.9), Stefan number (0.1–0.9), volume concentration of nanoparticles (0–0.05), Darcy number (10−4–10−1). Hartmann number (0–80) and the undulations of the inner (3–9). The numerical analysis has exploited the finite element approximations. The results indicate that Rayleigh and Hartmann numbers greatly influence the fluid flow, isotherms, concentrations and the melting/solidification region. The fusion has also a great influence on the melting/solidification region while there is no evident influence on the flow, isotherms and the concentrations where both Nusselt and Sherwood numbers change with around 5% with the change of the fusion temperature and Stefan number. In contrast, both values are decreased by around 30% by decreasing the Da number from 0.1 to 10−4. Furthermore, the change of the undulations number has very low influence on heat transfer, mass transfer and the melting/solidification region. © 2024 Wiley Periodicals LLC.

This study investigates the fluid-structure interaction and heat transfer characteristics of nano-encapsulated phase change material (NEPCM) in a magnetohydrodynamic (MHD) free convection system with a flexible wall. A finite element method coupled with the Arbitrary Lagrangian-Eulerian (ALE) approach was employed to solve the governing equations. The effects of key parameters were examined, including Rayleigh number (Ra = 103-105), Stefan number (Ste = 0.1-0.9), fusion temperature (θf = 0.1-0.9), NEPCM volume concentration (φ = 0.01-0.04), oscillation amplitude (A = 0.05-0.15), Hartmann number (Ha = 5-30), and magnetic field inclination angle (γ= 0°-90°). Results show that increasing Ra from 103 to 105 enhanced heat transfer by 256 %, while augmenting Ha from 5 to 30 diminished it by 36.4 %. NEPCM concentration significantly improved heat transfer, with φ = 0.04 yielding 31.5 % higher efficiency than φ = 0.01. An optimal fusion temperature of θf = 0.5 was identified, providing 6 % better performance than extreme values. The magnetic field angle of 45° offered marginally better heat transfer. These findings provide valuable insights for optimizing thermal management in MHD systems with PCMs and flexible boundaries. © 2025 The Authors.

A numerical investigation of double-diffusive natural convection and magnetohydrodynamics (MHD) in a circular cavity containing nano-encapsulated phase change materials (NEPCM) with a partial porous medium under magnetic field influence has been conducted. The governing equations were discretized using the Galerkin finite element method, and the resulting nonlinear system was solved through the Newton-Raphson iteration technique with PARDISO solver. The study examined the effects of key parameters including Rayleigh (Ra) number (10³-10⁵), Hartmann (Ha) number (0–61), Darcy (Da) number (10⁻⁵-10⁻¹), Lewis (Le) number (0.1–10), buoyancy ratio (2–6), nanoparticle volume fraction (0–0.05), and fusion temperature (0.1–0.9). Results show that increasing nanoparticle concentration from 0 to 0.05 enhances heat transfer (Nusselt number, Nu) by 128 % while reducing mass transfer (Sherwood number, Sh) by 10.3 % at Ra = 10⁵. The magnetic field demonstrates a significant suppressive effect, with Ha increasing from 0 to 61 reducing both Nu and Sh by approximately 55 % and 57 % respectively. An optimal fusion temperature of 0.6 was identified for heat transfer enhancement, while mass transfer showed minimal sensitivity to fusion temperature variations. The study reveals that proper selection of operating parameters, particularly Da and Le numbers, can improve system performance by up to 218 % in mass transfer and 158 % in heat transfer, providing valuable insights for the design of thermal energy storage systems incorporating NEPCM and porous media. © 2025 The Author(s)

The increasing prevalence of unmanned aerial vehicles (UAVs) across various fields requires the development of advanced fault detection and diagnostic (FDD) frameworks to prevent the severe consequences of undetected sensor and actuator failures. This review investigates the wide spectrum of FDD methodologies for UAVs, focusing on the paramount role of sophisticated yet intelligent systems in safeguarding operational integrity, particularly in near-human environments. An analysis of 32 seminal publications from well-recognized databases presents a trend towards converging signal processing and machine learning techniques using UAV specific fault detection keywords. This analysis underscores the trend of data-driven models capable of performing real-time diagnostics. The authors increase interest in hybrid methodologies that correlate the precision of signal processing and the adaptive nature of machine learning. These approaches aim to gain fault detection accuracy and achieve better prognostic capabilities. By deconstructing the strengths and weaknesses of various methods, this analysis concludes with the need for further research into upcoming new challenges. The review focuses on the investigation of synergistic strategies and encourages interdisciplinary collaboration for advancements in FDD methods. These initiatives will enhance UAV safety and reliability across a wide range of operational contexts. © The Author(s) 2025.

Thermal management systems incorporating phase change materials have gained significant attention due to their high energy storage capacity and temperature control capabilities. Recent advances in nano-encapsulated phase change materials (NEPCMs) combined with magnetic field control offer promising solutions for enhanced heat transfer applications. However, the combined effects of mechanical oscillations and magnetic fields on NEPCM performance remain unexplored in complex geometries. This study investigates natural convection in a U-shaped baffled cavity filled with a nano-encapsulated phase change material (NEPCM) water mixture, featuring an oscillating bottom wall and subject to an inclined magnetic field. The finite element method is employed to solve the governing equations, with the Arbitrary Lagrangian-Eulerian approach used to handle the moving boundary. A comprehensive parametric study explores the effects of Rayleigh number (103–105), Stefan number (0.1–0.9), fusion temperature (0.1–0.9), nanoparticle volume fraction (0.01–0.04), oscillation amplitude (0.07–0.2), Hartmann number (0−20), and magnetic field angle (0°-90°) on heat transfer performance. Results show that the Rayleigh number has the most significant impact, increasing the time-averaged Nusselt number by 129.8 % as Ra rises from 103 to 105. Nanoparticle volume fraction also significantly enhances heat transfer, with a 58.9 % increase in Nusselt number as ϕ increases from 0.01 to 0.04. The optimal oscillation amplitude of 0.07 achieves a maximum Nusselt number of 1.4377, while larger amplitudes reduce heat transfer efficiency by up to 4.5 %. These findings provide valuable insights for optimizing thermal management systems utilizing NEPCM nanofluids in complex geometries with phase change processes. © 2025 The Authors

This paper investigates the nonlinear free vibration behavior of porous functionally graded (PFG) sandwich plates under hygrothermal conditions. The material properties of the PFG plates are assumed to change continuously across the thickness governed by the volume fraction of composition. An enhanced rule of mixtures including the distribution of porosity throughout the cross-section was utilized for material modeling. The foundation medium is modeled as nonlinear, homogeneous, and isotropic, which is then solved by using Galerkin’s model. The study employs first-order shear deformation theory (FSDT) in the kinematic relations, and the equations of motion are derived using Hamilton’s principle. An analytical solution is developed for the PFG sandwich plates, assuming supported boundary conditions. The study thoroughly examines the fundamental natural frequency of PFG plates, considering the impacts of the hygrothermal environment, porosity volume percentage, and span-to-depth ratio. To validate the analytical results, a numerical analysis using finite element method (FEM) is performed using ANSYS software. Amaximum discrepancy of 11% was found between the two approaches. © 2025 Techno-Press, Ltd. http://www.techno-press.org/?journal=csm&subpage=8

Efficient thermal energy storage systems in solar collectors require enhanced heat transfer mechanisms. This study examines convective heat transfer in a partially porous evacuated tube solar collector manifold using phase change materials, magnetic fields, and porous media. The investigation focuses on heat transfer, mass transfer, and system irreversibilities. Results show that convective intensity dominates system performance, with a threefold increase in dimensionless convective flow strength enhancing heat transfer by 138 % and mass transfer by 304 %. Phase change material concentration shows opposing effects: a 13.7 % improvement in thermal transport but an 8.3 % reduction in mass transfer at higher flow intensities. Porous media characteristics significantly affect transport processes when permeability increases. Species diffusion and buoyancy forces demonstrate complex interactions affecting system behavior. Magnetic field application enables precise performance control. These findings provide design guidelines for optimizing solar collector efficiency through balanced parameter selection. © 2025

This study investigates double-diffusive transport and entropy generation in a wavy cylindrical enclosure containing Cu─H2O Casson nanofluid under magnetic field and thermal radiation effects. The governing equations were solved numerically using the finite element method with Galerkin formulation. The investigation covered parametric ranges including Rayleigh number (10³ ≤ Ra ≤ 10⁶), Hartmann number (0 ≤ Ha ≤ 40), magnetic field inclination (0° ≤ γ ≤ 90°), nanoparticle volume fraction (0 ≤ φ ≤ 0.15), Casson parameter (0.1 ≤ η ≤ 1), radiation parameter (0 ≤ Rd ≤ 4), thermal conductivity parameter (0 ≤ λ ≤ 4), Lewis number (0.5 ≤ Le ≤ 5), and buoyancy ratio (0.25 ≤ Nz ≤ 1.5). Results demonstrated that increasing Ra from 10³ to 10⁶ enhanced heat transfer by 60%, while increasing Ha to 40 reduced fluid circulation by 75%. The Casson parameter significantly influenced flow characteristics, with stream function values increasing by 75% as η approached Newtonian behavior. Thermal radiation parameters jointly moderated temperature gradients, with Rd causing a 15%–20% reduction in thermal stratification. The Lewis number and buoyancy ratio showed strong coupled effects, with the Sherwood number increasing by 150% as Le increased from 0.5 to 5. These findings have practical applications in advanced heat exchanger design, thermal energy storage systems, electronic cooling technologies, and biomedical devices, where controlled heat and mass transfer of non-Newtonian fluids is crucial. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

This study investigates the thermo-fluid dynamics of Cu-H2O Casson fluid in an H-shaped enclosure with corrugated cylinders, examining entropy generation, MHD, and radiation effects. The governing equations were solved numerically using the finite element method with Galerkin's weighted residual technique. The analysis explored various parameters including Rayleigh number (10³-10⁶), nanoparticle concentration (0–0.15), Casson parameter (0.1–1), radiation parameter (0–4), Hartmann number (0–40), magnetic field inclination angle (0°-90°), buoyancy ratio (0.25–1.5), and Lewis number (0.5–5). Results demonstrated that increasing Ra to 10⁶ with φ=0.15 enhanced heat transfer by 140%, while higher Casson parameter values (η=1.0) improved circulation intensity by 40% compared to η=0.1. The magnetic field showed significant control over flow characteristics, with Ha=40 reducing circulation strength by 45% compared to Ha=0. Combined radiation and thermal conductivity effects (Rd=4, λ=4) resulted in 30% more uniform temperature distribution. The Lewis number and buoyancy ratio significantly influenced mass transfer, with Sherwood number increasing by 300% at higher Le values. These findings provide valuable insights for designing efficient thermal management systems with applications in electronic cooling and heat exchanger optimization. © 2025 The Authors

Thermal systems utilizing nano-encapsulated phase change materials (NEPCMs) in complex geometries offer promising solutions for efficient energy storage and management under electromagnetic control. This study aims to investigate double-diffusive mixed convection and entropy generation in a π-shaped cavity with wavy lid containing NEPCM-water mixture subjected to a transverse magnetic field. The mathematical model employs the Boussinesq approximation for density variations while disregarding viscous dissipation and chemical interactions. Governing equations are solved using finite element analysis with Galerkin's method across wide parametric ranges of Reynolds (25–100), Richardson (0.1–10), Lewis (1–5), Stefan (0.1–0.9) numbers, fusion temperature (0.1–0.9), NEPCM concentration (0.01–0.04), and Hartmann number (0–80). Results demonstrate that Reynolds and Richardson numbers significantly enhance heat and mass transfer (up to 204 % increase in Nusselt number), while magnetic fields substantially suppress convective transport (60.5 % reduction in Nusselt number). NEPCM concentration improves thermal performance by 39.3 % with minimal effect on mass transfer. Entropy generation analysis reveals that thermal irreversibilities dominate, with both magnetic field strength and NEPCM concentration reducing system irreversibilities. These findings provide critical insights for optimizing thermal energy storage systems with electromagnetic regulation in applications ranging from solar collectors to electronic cooling solutions. © 2025 The Authors

Solar air heaters (SAHs) are among the most useful devices for collecting solar energy and utilizing it for heating purposes. The primary aim of this endeavor is to enhance the performance of SAH. This is accomplished by artificially roughening the surface of the absorber using ribs. A two-dimensional computational fluid dynamics study looks at how a novel I-shaped ribs affect hydraulic and thermal performance in the SAH channel was carried out. The re-normalisation group (Formula presented.) turbulence model is utilized for numerical simulation, and its accuracy is evaluated against proven correlations and literature findings. Various discrete rib parameters, such as pitch ratio ((Formula presented.) range 7.14–17.86) and relative width ratio ((Formula presented.) range 0.5–1), have been optimized for the Reynolds number ((Formula presented.)) range of 6000–21,000, considering a fixed value of relative roughness height ((Formula presented.)) of 0.042. The main findings for the SAH are presented in terms of the Nusselt number ((Formula presented.)), the friction factor ((Formula presented.)), the thermal–hydraulic performance parameter (THPP), and the visualization of various fluid characteristics. The results demonstrate that compared with a smooth SAH duct, the current rib geometries significantly improve heat transmission and fluid mixing, boosting (Formula presented.) by 2.498–2.978 times and (Formula presented.) by 2.812–4.393 times. The study determined the optimal rib characteristics of (Formula presented.) and (Formula presented.). This combination achieved a peak THPP of 2.014. A generalized correlation has been established for Nu and (Formula presented.) using the numerically projected results. © 2025 Wiley Periodicals LLC.

Thermal management systems integrating phase change materials face challenges in maximizing heat transfer efficiency for electronics cooling and energy storage applications. This study addresses the research gap regarding fluid-structure interaction and magnetohydrodynamic effects on nano-encapsulated PCM performance in complex geometries. We investigate thermal transport in a curvilinear enclosure containing NEPCM with an oscillating lower boundary and two cold cylinders under electromagnetic field influence. Using finite element methodology with specialized treatment for moving boundaries, we evaluate key parameters: Rayleigh number (Ra: 10³–10⁵), Stefan number (Ste: 0.1–0.9), phase transition temperature (θf: 0.1–0.9), NEPCM concentration (ϕ: 0.01–0.04), oscillation amplitude (A: 0.01–0.15), Hartmann number (Ha: 0–20), and magnetic field angle (γ: 0°–90°). Results reveal that increasing Ra from 10³ to 10⁵ enhances thermal efficiency by 122.9%, while nanoparticle addition improves performance by 37% as ϕ increases from 0.01 to 0.04. The electromagnetic field inhibits heat transfer, with Nu decreasing by 25.9% as Ha increases from 0 to 20. These findings provide design guidelines for thermal management applications in electromagnetically active environments. © 2025 The Author(s). Heat Transfer published by Wiley Periodicals LLC.

The optimization of heat transfer in various engineering applications, such as thermal management systems and energy storage devices, remains a crucial challenge. This study aims to investigate the potential of Casson-based Cu-H2O nanofluids in enhancing free convection heat transfer within complex geometries. The research examines the free convection heat transfer and fluid flow characteristics of a Casson-based Cu-H2O nanofluid within a semi-parabolic enclosure that includes a wavy corrugated cylinder. Utilizing numerical simulations based on the Galerkin Finite Element Method, the study investigates the impact of different factors, including the Rayleigh number (103 ≤ Ra ≤ 106), Casson fluid parameter (0.1 ≤ γ ≤ 1), corrugation number (3 ≤ N ≤ 10), nanoparticle volume fraction (0 ≤ ϕ ≤ 0.15), and enclosure inclination angle (0° ≤ ζ ≤ 60°), on both heat transfer efficiency and flow patterns. The results reveal that increasing the Rayleigh number and Casson fluid parameter enhances heat transfer performance, with the average Nusselt number increasing by up to 165 % as Ra increases from 103 to 106. An optimal range of corrugation numbers is identified for maximizing heat transfer at higher Rayleigh numbers. The addition of nanoparticles significantly improves heat transfer, with a 20 % increase in the average Nusselt number observed at Ra = 105 when the nanoparticle volume fraction increases from 0 to 0.15. These findings provide valuable insights for designing more efficient thermal management systems in applications such as electronics cooling, solar thermal collectors, and heat exchangers, potentially leading to improved energy efficiency and performance in various industrial and technological sectors. © 2024

This study focuses on the characterization of free vibration of composite shell structures strengthened by different volume fractions of nanoparticles analytically and numerically. Using simply supported boundary conditions, the governing differential equation of motion for the shell was formulated based on the Donnell-Mushtari-Vlasov (DMV) shell theory. For different design parameters, the natural frequency was investigated by employing the Orthogonality method. Four different layers of material, namely Perlon, Carbon, Kevlar, and Kenaf, of thickness 30 mm, were made. Nanoparticles Alumina (Al2O3) and Silica (SiO2) were chosen and mixed in varying volume fractions (0.5%, 1%, 1.5%, 2%, and 2.5%) for the sample fabrication. Two types of samples, A and B, were created based on the arrangement of layers. The tensile tests were performed on the fabricated specimens to identify the longitudinal Young’s modulus of specimens. The two groups that consist of different layers of materials were made and named as group A and group B. The results indicate an increase in Young’s modulus of 33.9% increase for nano Al2O3 and a 42.25% increase for nano SiO2 at a volume fraction of 2.5% for group A, while for group B, the enhancement was 37.96% and 47.39% for Al2O3 and SiO2 nanoparticles, respectively. The results indicate that as the volume fraction of nanomaterial is increased, the natural frequency increases. The experimental results are used to validate both analytical and numerical solution conducted by the finite element method (FEM) under various loading conditions. The maximum difference between the analytical and numerical prediction of the natural frequency results was within 5%. © 2025 by the Authors.

This paper numerically studied double diffusive free convection in a 2-D helical coil energy storage filled with nano-enhanced phase change material and a layer of porous foam. While previous studies have examined various aspects of energy storage systems, the combined effects of NEPCMs, magnetic fields, Soret/Dufour effects, and metallic foam in helical coil energy storage systems remain unexplored. This study presents the first comprehensive investigation of these combined effects, providing crucial insights for optimizing thermal energy storage systems. The cavity is rectangular with four circular heat sources on the right which are attached to a porous layer (0.1 W) while the cold is by the right wall. The considered parameters are Rayleigh number (103–105), fusion temperature (0.1 ≤ θf ≤ 0.9), Stefan number (0.1 ≤ Ste ≤ 0.9), the volume concentration of nanoparticles (0 ≤ ϕ ≤ 0.035), Darcy number, (10–4 ≤ Da ≤ 10–1), bouncy ratio (1 ≤ Nz ≤ 5), Lewis number (0 ≤ Le ≤ 10) and Hartmann number (0 ≤ Ha ≤ 50). The numerical analysis has exploited the finite element method. The main results state that the value of the Nusselt average increases with the increase of the volume concentration, bouncy ratio and fusion temperature while the Sherwood average shows reverse behavior to these numbers. On the other hand, average values of Nusselt and Sherwood are decreased with the rise of the Hartmann number. Furthermore, Nusselt average and Sherwood's average decrease by 21.4 % and 24.9 % respectively when Darcy's number increases from 0.1 to 10-4. © 2025 The Author(s)

This work presents a suggested analytical solution for a forced vibration of an aircraft sandwich plate with a honeycomb core under transient load. The differential equation of motion is first derived and then solved by using the separation of variables method. The plate’s transient response and maximum transient deflection are studied with various design parameters. First, the analytical results are figured out using the honeycomb structure’s mechanical properties, such as its density, Poisson’s ratio, modulus of elasticity, and modulus of rigidity. Next, the effect of the honeycomb structural properties on the transient response and the maximum transient deflection is determined. Then, the cell size, core height, and cell wall thickness are selected as the honeycomb structural parameters. The ANSYS 19.2 software package is utilized to perform the finite element simulation for the sandwich panel with the honeycomb core. This study conducted modal and transient response analyses to derive the numerical transient response and maximum transient deflection. The results demonstrate a strong concordance between the analytical and numerical results with a 95% conformity rate. Moreover, the results demonstrate an inverse relationship between the transient response and both the core height and cell wall thickness, while it is directly proportional to the cell size. This relationship is derived from the theoretical equations and further validated through numerical simulations, showing strong agreement between analytical and computational results. © 2025 by the authors.

The present paper computationally investigates the influence of fins on phase change material (PCM) melting within a rectangular enclosure. ANSYS/FLUENT 16 was used with the enthalpy-porosity method to simulate the phase change in paraffin wax (RT42). Four cases were taken into account: a finless model and three fin models of varying lengths (5 mm, 10 mm, and 15 mm). Results indicate that fins enhance heat transfer by enhanced conduction and thus accelerate the phase change in melting. In the absence of fins, melting occurs primarily through natural convection, leading to a delay in phase transition. The addition of 5 mm fins reduces melting time by 25%, whereas 10 mm and 15 mm fins reduce it by 38% and 50%, respectively. The results highlight that a higher length of fins greatly increases the spreading of heat and the effectiveness of melting. This research points out the efficacy of fins in enhancing thermal energy storage systems and presents valuable lessons for the development of the efficiency of PCM-based heat storage systems. The results present valuable guidelines for developing efficient thermal management systems for renewable energy storage, electronics cooling, and industrial heat recovery systems. © The Author(s), under exclusive licence to The Brazilian Society of Mechanical Sciences and Engineering 2025.

Latent heat storage technology has been receiving significant attention from scientists, researchers, and engineers working in solar heating and cooling, waste heat recovery, as well as building energy management. Phase change materials (PCMs) have been extensively utilized for this purpose due to their high energy storage capacity and cost-effectiveness. In this study, a numerical investigation was conducted to evaluate heat transfer in paraffin wax RT42 during its complete phase transition from solid to liquid within a square cell, both with and without an air layer on the left hot wall, with the rest of the walls thermally insulated. The enthalpy-porosity approach was quantitatively analysed using the ANSYS/FLUENT 16 program. The results indicate that the presence of a 1 mm thick air layer doubled the complete melting time, and a 2 mm thick air layer tripled the melting time compared to scenarios without an air layer. Additionally, it was shown that thermal conduction drives early melting, while density differences influence free convection in later stages. This study underscores the significant impact of air layers in delaying the melting process of PCMs paraffin wax in square latent heat storage units. Furthermore, guidelines for future investigation were provided, including examining the effects of adding air layers and providing a heat flow from the top or bottom of the square cell. This further research might assist in revealing more specifics of the interactions among the environment, phase change mechanisms, and heat transport in thermal energy storage systems. © The Author(s) 2025.

In recent years, the growing demand for electricity has underscored the need for efficient energy storage solutions. This study investigates the energy storage, hydrothermal performance, and entropy analysis of micro-polar nano-encapsulated phase change materials (NEPCMs) under the influence of an exothermic reaction and an external magnetic field. The novelty of this work, which focuses on energy storage applications, lies in the use of a novel geometry and a range of highly effective parameters. The numerical study explores the physical interactions between heat and mass transfer, considering a wide range of parameters, including the Rayleigh number (103 ≤Ra≤ 105), Lewis number (0.1 ≤ Le ≤ 10), buoyancy ratio (1 ≤ Nz ≤ 5), Hartmann number (0 ≤ Ha ≤50), magnetic field inclination angle (0o ≤ γ ≤ 90o), Frank-Kamenetskii number (0 ≤ FK ≤ 2.5), NEPCM concentration (0.01 ≤ ϕ ≤ 0.035), fusion temperature (0.01 ≤ θf ≤ 0.035), Stefan number (0.1 ≤ Ste ≤0.9), and aspect ratio (0.5≤AR≤1.5). The results demonstrate that increasing Ra enhances the average Nusselt number (Nuav) by up to 429.9 % and the average Sherwood number (Shav) by up to 206 %, while increasing the total entropy generation (Stotal) by up to 13,014 %. Increasing FK reduces Nuav by up to 27.8 % but increases Shav by up to 42.7 %. The Le, Nz, and ϕ significantly impact the hydrothermal performance and entropy generation, with Nuav increasing by up to 36.3 % and Shav decreasing by up to 5.6 % as ϕ increases. The Ha substantially reduces Nuav and Shav by up to 62.3 % and 31.2 %, respectively, while the γ exhibits a non-monotonic behavior with an optimal angle around 60°. The most prominent conclusions highlight the complex interplay between various parameters, with Ra, Le, Nz, and Ha having substantial effects on the hydrothermal performance and entropy generation. The findings provide valuable insights for optimizing the design and operation of energy storage systems based on micro-polar NEPCMs. © 2025 The Authors

This pioneering study presents a novel investigation of the complex interplay of magnetohydrodynamic (MHD) free convection, double-diffusion, and exothermic reactions in a square cavity with a unique configuration. A corrugated porous layer with a thickness of 0.2L adheres to the left wall. The cavity is partially filled with a nano-enhanced phase change material (NEPCM) suspended porous medium. This innovative design combines the benefits of corrugated surfaces, NEPCMs, and magnetic field control for enhanced thermal management. Using the Galerkin finite element method and PARDISO solver, a comprehensive numerical analysis investigates the effects of various parameters on heat transfer, mass transfer, and entropy generation. These parameters include Frank-Kameneteskii number (0≤FK≤2.5), Darcy number (10−5≤Da≤10−2), Rayleigh number (103≤Ra≤105), buoyancy ratio (1≤Nz≤5), Lewis number (0.1≤Le≤10), fusion temperature (0.1≤θf≤0.9), Stefan number (0.1≤Ste≤0.9), magnetic field inclination (0°≤γ≤90°), Hartmann number (0≤Ha≤50), and NEPCM concentration (0.01≤ϕ≤0.035). Results demonstrate that increasing Ra from 103 to 105 enhances the average Nusselt number by 324 % at FK=1. Nanoparticle volume fraction significantly improves heat transfer, with a 67.6 % increase in Nusselt number as ϕ rises from 0.01 to 0.035. The magnetic field suppresses convection, reducing Nusselt and Sherwood numbers by 57.8 % and 27.4 %, respectively, as Ha increases from 0 to 50. Entropy generation decreases by 84 % under the same conditions. These findings are particularly relevant for designing advanced heat exchangers, solar thermal systems, and electronic cooling applications, where precise control of heat transfer and thermal energy storage is crucial. © 2025 The Authors

Until now, there has been a lack of two-phase velocity and vapor investigations under the evaporation condition. Therefore, this work addresses this title in order to be additive to this subject. The spray droplets are modelled using the moments method, and the gas phase is modelled using the Eulerian approach. The spray drag, breakup, and evaporation sub-models are taken into account. Based on the RANS turbulence model for the carrier gas phase and a calibrated atomisation model for the dispersed droplets, turbulence closure is accomplished. The spray tip penetration is evaluated and compared with experimental data. The fuel vapour mass fraction is calculated by using a transport equation for the droplet-gas interaction. The distribution of the fuel vapour mass fraction is compared with the KIVA code. Fortunately, there are no experimental results for the spray or gas velocity to be compared with. All presented results are investigated by their variation with positions and time to give the total behaviour. The fuel vapour mass fraction distribution exhibits a bell-shaped behaviour. In close proximity to the injector, the evaporation rate is significantly higher. There was no significant increase in the evaporation rate of the pressure swirl nozzle as the distance from the injector increased. During the evaporation of spray droplets, higher fuel vapour concentrations are present at the core spray than at the peripheral edge. The droplet velocities in the outer edge's axial and radial directions display a reduced magnitude. The droplet's diameter is greater at the inner edge than at the outer edge. The comparisons showed that there was good agreement with both the experimental and numerical results. © 2024 The Authors

This paper investigates numerically the effect of MHD and entropy generation on double-diffusive combined convection in an inclined enclosure filled with Si2O/H2O and heated fins. The geometry's base is connected to double fins with three locations in three cases. A range of variables has been considered, such as Reynolds, Richardson, Lewis, bouancy ratio, the volume fraction, Hartmann numbers, and the orientation of the enclosure, to investigate how these variables can affect the fluid flow and the mass and thermal transfer. The finite element method has been applied to solve these variables, and the main findings indicated that the value of average Nusselt and Sherwood numbers increases with the increase of volume fraction, Richardson, and Lewis numbers while decreasing with the increase of magnetic strength, Hartmann number. Where Nuavg and Shavg increase to 65% and 19% when increasing Re from 40 to 180 while both values decrease to around 35% when increasing Haatmann number from 0 to 62. Moreover, increasing the volume concentration from 0 to 0.08 increases Nuavg and Shavg to around 3% and 12% respectively. Furthermore, the average Sherwood number increases with the increase in inclination angle. In contrast, the average Nusselt decreases with the increase in the inclination angle, except for the right angle, which gives a higher value. Moreover, the total average entropy generation is reduced with the increase of the magnetohydrodynamic and buoyancy ratio while increasing with the rise of Reynolds, Richardson, Lewis, and the concentration of the nanoparticles. Also, the lowest values of entropy generation are generated in Case 3, while CaseI generates the highest values of entropy generation. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

This study presents a numerical investigation of the effect of geometrical parameters on the thermal and hydraulic performance of a compact spiral coil heat exchanger (SCHE) using the commercial CFD code. Compact SCHEs are gaining importance due to their high surface-area-to-volume ratio and their ability to enhance fluid mixing through secondary flows, making them highly suitable for power generation, refrigeration, chemical processing, and renewable energy systems. Two key parameters, the number of coil turns and the coil pitch, were systematically analyzed under various Reynolds numbers. The evaluation was performed regarding heat transfer coefficient, Nusselt number, pressure drop, and the overall thermal performance factor, reflecting the trade-off between thermal enhancement and hydraulic losses. The results showed that the three-turn configuration consistently outperformed the four-turn configuration, especially at lower Reynolds numbers, due to reduced flow resistance and lower pumping requirements. Similarly, increasing the coil pitch from 40 mm to 55 mm improved overall thermal performance across all flow conditions by promoting better fluid circulation and reducing pressure drop, while maintaining strong heat transfer. The findings confirm that a three-turn coil with a pitch of 55 mm represents the most effective design among the cases studied, providing the optimal balance between heat transfer efficiency and hydraulic performance. The results demonstrated that the three-turn configuration (Case A) consistently outperformed the four-turn design (Case B). AtRe = 10,000, Case A achieved a maximum η of around 1.96 compared to around 1.33 for Case B, representing an improvement of nearly 47 %, while atRe = 16,000, Case A maintained a around 14 % advantage. Similarly, increasing the coil pitch from 40 mm to 55 mm enhanced performance across all Reynolds numbers. AtRe = 10,000, the wider pitch provided η ≈ 1.61, 29 % higher than the 40 mm pitch case. Even atRe = 16,000, the 55 mm pitch retained a 7 % improvement. © 2025 The Authors.

The applications of composite materials have been increasing significantly in recent decades due to their superior mechanical properties and versatility. The major effect limiting the use of composite materials is the lack of understanding of their response and their structural integrity under dynamic loads. Among the prominent damage mechanisms, the debonding under dynamic loading is a well-recognized failure mode for laminated composites. Up to date, the impact of the significant parameters on the delamination is thoroughly examined in this study with primary focus on the hemispheric indenter diameter and the characteristics of the exerted load applied at constant energy levels. The damage morphology has been carefully investigated using X-ray computed tomography, quantifying the shape and size variation of delamination areas across plies. The experimental observations have been incorporated into the finite element modeling, carried out in ABAQUS, by means of cohesive elements, which allow for the setting of a failure criterion. The main delamination area has been confirmed to be localized on the tension side of the laminate, where the most bending stress is sustained. Moreover, the angular difference between adjacent plies that articulates the distribution of the interlaminar stresses has to be taken into consideration, since it has a great impact on the extent of delamination. It is concluded that the initiation of delamination can be detected using a delamination threshold load based on the quasi-static load-displacement curve. These results illustrate the importance of the indenter radius to thickness ratio as a governing parameter in the structural response of composite plates, aiding in the development of more accurate predictive models for damage assessment. © 2025 Techno-Press, Ltd.

To meet the growing need for sustainable energy solutions, improving the efficiency of thermal energy storage (TES) systems is important. In this study, the melting behavior of RT42 paraffin wax inside a hexagonal multi-cell was analyzed using numerical simulation based on the enthalpy-porosity method with ANSYS/FLUENT 16 software. The study focused on evaluating the effect of changing the thickness of the central air layer on the melting efficiency of the phase change material (PCM). Four cases were tested: one without an air layer and three others with thicknesses of 2 mm, 4 mm, and 6 mm. The results showed a clear quantitative relationship between the thickness of the air layer and the increase in melting time. The total time increased from 660 min (without air) to 780 min with a 2 mm thick air layer, an increase of 18%. The time reached 900 min at a thickness of 4 mm (37%) and 960 min at 6 mm (50%). These results show how important internal air layers are in reducing heat transfer efficiency, and how important it is to take them into account when designing phase change material-based thermal energy storage systems to get better performance and sustainability. © The Author(s) 2025.

The current study is concerned with a numerical investigation of the process of heat transfer and flow inside an innovative cavity that was inspired by the shape of the nasal cavity. The nasal cavity was modeled as a channel with hot air entering at temperature Th through one opening, exchanging heat with the lower isothermal cold wall at Tc, and exiting the opposite side. A finite element method was employed to solve the laminar, incompressible Navier-Stokes equations coupled with the energy equation over a range of Reynolds numbers (10 ≤ Re ≤ 200) and Richardson numbers (0.1 ≤ Ri ≤ 10). The results elucidate how the interplay between forced convection from the inlet flow and natural convection from heating influences the overall flow regime, recirculation structure, temperature distribution, and heat transfer rates within the cavity. As Ri increased (natural convection became more prominent), buoyancy established strong recirculation cells that amplified swirling and heat transfer, especially at intermediate Re~50 coupling the convection modes. However, very high Re could disrupt the coherent natural convection cells at high Ri, diminishing some of the heat transfer enhancement. © 2025 American Institute of Physics Inc.. All rights reserved.

Numerical study of free convection in an octangle cavity filled with Cu/water nanofluid under the MHD and radiation effect has been invested in this paper. The finite element method has been considered for the numerical study. A range of variables have been considered such as Rayligh number (103 ≤ Ra ≤ 106), Hartmann number (0 ≤ Ha ≤ 60), Darcy number (10-5 ≤ Da ≤ 10-2), volume concentration (0 ≤ ϕ ≤ 0.06), Radiation parameter and (0 ≤ Rd ≤ 10). The main results stated that the transfer of heat and the fluid flow are higly affected by the considered parameters, where the value of Nu average highly increase with the increase of Ra, Da, λ,ϕ and Rd while decreases with the increase of the Ha number. © 2025 American Institute of Physics Inc.. All rights reserved.

This study investigates the thermal–hydraulic performance of a nanoencapsulated phase change material (NEPCM) suspension in a rectangular enclosure featuring two counterrotating cylinders positioned between three fixed hot and three fixed cold cylinders under magnetic field influence. The system's governing equations, incorporating mixed convection, phase change, and magnetohydrodynamic (MHD) effects, were solved using the Galerkin finite element method. A comprehensive parametric analysis explored dimensionless parameters, including Reynolds number (10–100), Richardson number (0.1–10), Hartmann number (0–80), Lewis number (0.1–10), and NEPCM volume fraction (1%–4%). Results demonstrated significant enhancement in heat and mass transfer characteristics with increasing flow rates and buoyancy effects, showing up to 84% improvement in the average Nusselt number at low Richardson numbers. A noticeable influence of the magnetic field showed a substantial impact on the system performance, reducing both thermal and solute transformation rates by approximately 54% and 62%, respectively, at maximum field strength. However, higher NEPCM concentrations partially offset this reduction, improving thermal performance by 46% at maximum particle loading. The resulting outcomes provide valuable insights for optimizing MHD heat exchangers, exploding NEPCM suspensions with localized mixing enhancement through counterrotating cylinders. © 2025 The Author(s). Heat Transfer published by Wiley Periodicals LLC.

This study investigates entropy generation and heat transfer in a circular cavity containing immiscible air and TiO2–water nanofluid layers with a centrally positioned active cylinder under oscillating magnetic field influence. The governing equations were solved using the Galerkin weighted residual finite element method with a penalty formulation. The study examined the effects of Rayleigh number (10³ ≤ Ra ≤ 10⁶), Hartmann number (0 ≤ Ha ≤ 80), magnetic field wavelength (0.1 ≤ λ ≤ 0.9), nanoparticle volume fraction (0 ≤ ϕ≤ 0.05), and active cylinder position (bottom, top, center, and right). Results indicate that cylinder position significantly impacts thermal performance, with the bottom configuration yielding up to 94.1% higher heat transfer rates than the top position. Increasing magnetic field strength progressively suppressed convective flows, reducing heat transfer by up to 16.9% while decreasing entropy generation by up to 82.3%. Nanoparticle addition enhanced heat transfer across all configurations by up to 23.8% as concentration increased from ϕ = 0.01 to 0.1, though at the cost of increased system irreversibility. The top position demonstrated remarkable thermal stability across varying Rayleigh numbers, making it suitable for applications requiring consistent performance. These findings provide valuable insights for optimizing thermal management systems involving immiscible fluids under electromagnetic influence, with applications in electronics cooling and energy systems. © 2025 The Author(s). Heat Transfer published by Wiley Periodicals LLC.

The properties of a semi-closed combined cycle power system make it a better option for this study than an open system, since it turns an open-cycle gas turbine into a pollutant-free power system. Also in the selected cycle, the exhaust is channeled toward a divider rather than being released into the atmosphere, and the exhaust is divided into a separation duct and a return duct by the divider. Part of the exhaust is directed back toward the compressor via the return duct. This study investigates the effect of thermodynamic parameters analysis (turbine inlet temperature, ambient air temperature, pressure ratio, and regenerator effectiveness) on thermal efficiency and specific fuel consumption (S.F.C.) for a semi-closed system. The properties of a semi-closed combined cycle power system make it a better option for this study than an open system, since they turn an open-cycle gas turbine into a pollutant-free power system. Also in the selected cycle, the exhaust is channeled toward a divider rather than being released into the atmosphere. The exhaust is divided into a separation duct and a return duct by the divider. Part of the exhaust is directed back toward the compressor via the return duct. This study investigates the effect of thermodynamic parameters analysis (turbine inlet temperature, ambient air temperature, pressure ratio, and regenerator effectiveness) on thermal efficiency and S.F.C. for a semi-closed gas turbine cycle. The operating conditions are taken into account when determining the analytical formulas for assessing thermal efficiency and S.F.C., which are calculated by using thermodynamic equations. The model is constructed using MATLAB®. The results show that the thermal efficiency is increased due to increased turbine inlet temperature, increased regenerator effectiveness, and decreased ambient air temperature. Conversely, S.F.C. decreases. It was also found that when the pressure ratio was roughly 2, the thermal efficiency rose, while the S.F.C. started to decrease. After this value, the thermal efficiency began to decline gradually, and the S.F.C. increased. Also, as the regenerator's effectiveness increased to roughly 0.95, the data indicate that the thermal efficiency achieved its maximum value of 0.60. and at a turbine inlet temperature of about 1600 K, while the S.F.C recorded a minimum value of 0.1394. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

The work aims to investigate the MHD Casson fluid flow over an exponentially long sheet via a thermally stratified permeable medium. All facets of chemical processes, Joule heating, and exponential heat sources are covered in this subject. By using the appropriate similarity conversions, the leading partial differential equations (PDEs) of the model are transformed into a set of nonlinear ordinary differential equations (ODEs). The description of the previous technique was made simpler by applying the Keller Box methodology. The results reveal that when the viscosity factor is increased, the velocity profile improves, but when the thermal profile improves, the opposite trending impact is evident. The temperature profile exhibits the opposite tendency, despite a decline in the number of observations of the Casson fluid constraint. Joule heating parameters allow for more precise measurements of the heat source’s properties by raising the temperature. The concentration graph shows a reduction as the number of observations for the chemical reaction parameter increases. The validity of the problem is investigated by computing the Nusselt number for cumulative Prandtl number observations and comparing the results with the literature. © 2025 University of Al-Qadisiyah. All rights reserved.

This study numerically investigates thermal transport and fluid dynamics in a triangular cavity filled with a MgO–Ag–H2O hybrid nanofluid containing an undulating porous fin under electromagnetic field and thermal radiation influences. The governing equations are solved numerically using the Galerkin finite element methodology with Darcy–Forchheimer formulation for porous media representation. A comprehensive parametric study examines the effects of Rayleigh number (Ra, 10³–10⁶), Darcy number (Da, 10⁻⁵–10⁻²), Hartmann number (Ha, 0–80), magnetic field orientation angle (γ, 0°–90°), nanoparticle concentration (φ, 0.005–0.02), heat generation coefficient (λ, 1–5), fin waviness parameter (nw, 0–6), and radiation intensity factor (Rd, 1–5). The numerical model is validated against established benchmark solutions, demonstrating excellent agreement. Findings demonstrate that increasing Ra substantially improves thermal transport and flow intensity, with the average Nusselt number rising by up to 65% and maximum velocity magnitudes increasing by over 500 times. Electromagnetic field application inhibits thermal transport, with (Nuav) decreasing by 55.6% as Ha increases from 0 to 80. Magnetic field angle optimization shows that γ = 60° provides better heat transfer than γ = 0° at high Ha values. Nanoparticle addition provides moderate thermal enhancement, with an 11.1% increase in Nuav as φ increases from 0.005 to 0.02, particularly in low-Ra regimes. Radiation effects become most significant at elevated Ra values, with (Nuav) nearly tripling as Rd increases from 1 to 5 at Ra = 10⁶. Entropy generation analysis reveals that the Bejan number decreases by 98.7% as Ra increases, indicating fluid friction dominance at higher Ra values. These results offer essential guidance for optimizing thermal management systems involving porous structures, nanofluids, and electromagnetic fields. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

This article presents a numerical and experimental investigation of the application of vibration-based damage detection methods for quantifying delamination and fibre breakage in laminated composite structures. Modal curvature, enhanced irregularity, and a Harr index have been utilised to run the signal processing analysis. Numerically, the carbon fibre reinforced polymer is simulated in the software “ABAQUS 6.14-1” to show the effects of the damaged areas on the modal characteristics of laminated composite structures. Due to the well-known effect of damage that reduces local stiffness in mechanical structures, fibre breakage is simulated by assuming the mechanical properties of the matrix (epoxy) in the damaged areas, while the delaminated areas are represented by adding a very thin layer with the mechanical properties of the unperforated release film to separate the adjacent layers. Within this framework, an analysis of delamination and fibre breakage is presented, which to the best of our knowledge has not been previously investigated. © The Author(s), under exclusive licence to Shiraz University 2025.

PCMs store thermal energy during phase transitions without temperature changes, making them valuable for various thermal applications. When direct PCM use isn't practical, researchers have developed encapsulation methods as an alternative approach. Computational models can simulate various aspects including temperature patterns, species movement, fluid behavior, phase change regions, transport coefficients, energy utilization, and thermal performance metrics. This study explores the thermodynamic and flow characteristics of double-diffusive convection in systems where nano-encapsulated phase change materials are suspended in elliptical tube configurations, with additional consideration of exothermic chemical reactions. The investigation considers parameters including Rayleigh values (103–105), Lewis number (0.1–10), Hartmann number (0–50), buoyancy proportions (1–5), NEPCM densities (0.01–0.035), relative melting points (0.1–0.9), Stefan number (0.1–0.9), magnetic field alignments (0°–90°), and Frank-Kamenetskii number (0–2.5). Analysis shows that NEPCM concentration and magnetic field properties significantly affect both thermal-hydraulic efficiency and entropy development. The complex relationships between parameters (Ra, FK, Le, Nz, ϕ, Ha) reveal their significant roles in determining heat transfer effectiveness and irreversibility formation. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

Overheating, decreased performance, and system failures can result from ineffective thermal management in electronics, energy systems, and industrial processes where high-efficiency heat exchange is essential. This study delves into the sophisticated heat transfer characteristics and flow dynamics of an aluminum oxide-water nanofluid filled in a circular configuration containing a chamfered square heater at its center. Optimizing the efficiency of heat transfer requires an understanding of how nanofluids behave in these geometries. The study employs numerical simulations to comprehend different factors' impact on fluid dynamics and heat exchange process. The operating parameters, such as Rayleigh number (103 (Formula presented.), Frank–Kamenetskii factor ((Formula presented.), Hartman number (Formula presented.), heater diameter to enclosure diameter ratio ((Formula presented.), and concentration of nanosolids ((Formula presented.)), were methodically investigated. The methodology includes solving the governing equations for mass, momentum, and energy conservation utilizing the finite element technique. In contrast to earlier research on straightforward heaters, this study examines a chamfered square heater and shows how its shape affects flow and heat transfer in response to magnetic fields and nanoparticle loading. The investigation outcomes reveal that raising the Rayleigh number to 105 causes convection enhancement, increasing fluid speed by more than 5.81% and heat transfer efficiency and significantly raising the average Nusselt number by 187.5%. While increasing the Frank–Kamenetskii factor to Fk = 4 has no effect on flow dynamics, it may decrease the average Nusselt number by 63%, which would lessen the efficiency of heat transmission. Furthermore, changing the chamfered square heater's diameter impacts heat transmission and fluid motion, with smaller diameters encouraging greater heat exchange and higher fluid velocities. Aluminum oxide nanoparticles remove vortices and improve thermal conductivity to improve fluid motion and heat transmission; nevertheless, fluid velocity is hindered by overly high concentrations of the nanoparticles. Reducing the Hartman number highlights the impact of magnetic field intensity on nanofluid behavior by increasing fluid velocity and heat transfer by achieving a rise in Nuavg of 22.4%. By clarifying the complex relationships between operating parameters and nanofluid behavior in enclosed geometries, these findings aid in the optimization of thermal management systems. © 2025 The Author(s). Energy Science & Engineering published by Society of Chemical Industry and John Wiley & Sons Ltd.

This study examined the effects of adding hydrogen to flammable liquid fuel droplets on emissions. It was found that an optimal mixing ratio with hydrogen can reduce the amount of NOx in the reaction zone, which is the area where the primary combustion reactions occur. N-pentane is burnt in air enriched with different amounts of hydrogen, and the effects of the amount of hydrogen in the air on the combustion and emission parameters are investigated numerically. The combustion is modelled with the PDF/mixture fraction, and standard two-equation turbulence models and thermal NOx models are used for this modelling. The determination of the optimum H2 blending ratio is evaluated after the estimation results. It is evident that the addition of H2 led to an increase in spray flame temperatures. As a result, the addition of H2 increases the combustion performance of n-pentane. The emissions evaluation results show that a blending ratio of 20% H2 reduces CO emissions at the combustion's reaction zone and also results in a decrease in the mixture fraction. There is an increase in NOx emissions due to the increase in spray flame temperatures. Combustion under air conditions containing 20% H2 by volume resulted in the highest temperature levels reaching 2130 K, while the reduced NOx levels decreased to approximately 11.3%. The thermal NOx model, when combined with the combustion model, provides a sufficient level of agreement with the experimental data. © 2025 The Authors

Magnetohydrodynamic and entropy generation of double-diffusive mixed convection in a curvilinear cavity filled with nano-enhanced phase change material and a rotating cylinder has been studied in this paper. Three heat sources have been considered and a range of different variables such as Reynolds number (10 ≤ Re ≤ 100), Richardson number (0.1≤ Ri ≤ 10), Hartmann number (0≤ Ha ≤50) Lewis number (0.1≤ Le ≤ 0.9), bouncy ratio (1≤ Nz ≤ 5), fusion temperature (0.1≤ θf ≤0.9) and Stephan number (0.1≤ Ste ≤0.9). These variables have been numerically solved by applying the Finite Element Method. The main results indicated that heat transfer, mass transfer and heat capacity are hugely increased with the increase of the Re, Ri and volume concentration while decreasing with the increase of the Ha number and entropy generation. Furthermore, the melting/solidification region is hugely influenced by the fusion temperature while this variable has a negligible influence on streams, heat transfer and mass transfer. Furthermore, the value of the average Nusselt number and average Sherwood number has increased by 328 % and 258 % respectively by increasing the Reynolds number from 10 to 100. Also, these two numbers have decreased by 61 % and 54 % respectively by increasing the Hartmann number from 0 to 20. © 2024

Efficient cooling of integrated circuits is crucial for maintaining optimal performance and longevity of electronic devices. This study addresses this challenge by investigating the double-diffusive mixed convection around a hot integrated circuit (using) a nano-encapsulated phase change material-water mixture for enhanced heat absorption. The cooling process is carried out by a cylinder rotating at a constant speed inside a square cavity surrounded by the NEPCM-water mixture. Using the Galerkin finite element method, we numerically analyzed the influence of various parameters, including the Reynolds number (10≤Re≤100), Richardson number (0.1≤Ri≤10), Hartmann number (0≤Ha≤80), NEPCM volume fraction (0.01≤ϕ≤0.035), Lewis number (0.1≤Le≤10), buoyancy ratio (1≤Nz≤5), fusion temperature (0.1≤ϴf≤0.9), and Stefan number (0.1≤Ste≤0.8), on the average Nusselt number (Nuav), average Sherwood number (Shav), total entropy generation (Stotal), and Bejan number (Be). The results demonstrate that increasing Re and Ri enhances Nuav and Shav by up to 175 % and 162 %, respectively, while applying a magnetic field (increasing Ha) suppresses heat and mass transfer rates by up to 58 % and 50 %, respectively. Increasing ϕ improves Nuav by up to 34 % with minimal impact on Shav. The Le and Nz govern the coupling between heat and mass transfer processes, with Le substantially influencing Shav and Nz affecting both Nuav and Shav. The ϴf exhibits a non-monotonic effect on Nuav, suggesting an optimal fusion temperature, while Ste shows an inverse relationship with Nuav. The Stotal is significantly influenced by Re, Ri, Ha, and ϕ, while Be is affected by Re, Ri, Ha, and ϕ to a lesser extent. These findings provide valuable insights into the complex interplay of forced and natural convection, magnetohydrodynamics, and NEPCMs in the active cooling of hot electrical elements. The results can be applied to optimize cooling system designs, potentially leading to more efficient and effective thermal management in electronic devices. © 2024

This study investigates the cooling of a central processing unit (CPU) using a nano-encapsulated phase change material (NEPCM)-water mixture in a trapezoidal cavity with rotating cylinders and baffles. A numerical model based on the finite element method (FEM) is employed to solve the governing equations. The system is subjected to a sinusoidal temperature profile from the CPU and a constant magnetic field. Key parameters examined include Reynolds number (Re: 10–100), Richardson number (Ri: 0.1–10), Hartmann number (Ha: 5–80), NEPCM volume fraction (ϕ: 0.015–0.035), Lewis number (Le: 0.1–10), buoyancy ratio (Nz: 1–5), NEPCM fusion temperature (θf: 0.1–0.9), and Stefan number (Ste: 0.1–0.9). Results show that increasing Re and Ri significantly enhances heat and mass transfer, with the average Nusselt number (Nuav) increasing by up to 80.5 % and average Sherwood number (Shav) by up to 147.9 %. The magnetic field suppresses convection, reducing Nuav by 12.7 % and Shav by 39.5 % as Ha increases. Increasing ϕ improves heat transfer (Nuav up by 32.5 %) with minimal effect on mass transfer. Le strongly influences mass transfer, with Shav increasing by 284.6 % as Le increases. The NEPCM fusion temperature exhibits a non-monotonic effect on Nuav, with an optimal value at θf = 0.5. In conclusion, the study reveals complex interactions between parameters, with Re, Ri, and Le having the most significant impacts on system performance. These findings provide valuable insights for optimizing CPU cooling systems using NEPCM-water mixtures and magnetohydrodynamic (MHD) effects. © 2024

This study presents a novel investigation into the thermal behavior of a hybrid nanofluid (MgO − Ag − H2O) in natural convection around a porous fin in a triangular enclosure under the influence of radiation and magnetohydrodynamic effects. The research uniquely combines these complex phenomena, addressing a significant gap in the literature. This configuration has potential applications in advanced solar thermal collectors, electronic cooling systems for high-power devices, and compact heat exchangers in various industries. The main objectives are to understand how various parameters influence heat transfer and fluid flow behavior and to optimize the design for enhanced thermal performance. The study considers a range of variables including Rayleigh number (103 − − 106), Hartmann number (0 – 50), Aspect ratio (0.3 – 0.6), radiation parameters (Rd = 1 − − 5, λ = 1 − 5), and volume concentration (0- 0.05), which have been numerically analyzed using the finite element method (FEM). The findings reveal that increasing the Darcy number (Da) enhances heat transfer at low Rayleigh numbers (Ra = 103,104). However, at higher Ra (Ra = 106), the impact of Da becomes more complex, with a critical Da beyond which heat transfer efficiency decreases due to an increase in flow resistance. The nanoparticle volume concentration plays a vital role, as higher concentrations lead to improved heat transfer efficiency, especially at higher Ra, through enhanced thermal conductivity and thermal dispersion. The length of the porous fin greatly impacts fluid flow patterns and heat transfer rates, with longer fins creating more complex flow patterns, promoting enhanced heat transfer and stronger thermal plumes. Thermal radiation, represented by the radiation parameters (Rd and λ), significantly influences both the heat transfer rate and the convective flow patterns within the enclosure. This study also incorporates a comprehensive entropy generation analysis, providing novel insights into system irreversibilities and optimization potential. The entropy analysis reveals the complex interplay between various parameters and their impact on system efficiency, offering valuable guidance for designing high-performance thermal management systems. © 2024 The Author(s)

Double diffusive natural convection of the nano-encapsulated phase change material in a circular cavity with partial porous foam and fins has been searched in this paper. Furthermore, this study considered the influences of the magnetohydrodynamic, Soret and Dufour and the governing equations have been solved by applying the Finite Element Method. The variables with different values that have been studied in this research are Rayleigh number (103−105), Darcy number (10−4−10−2), fusion temperature (0.1−0.9), Stefan number (0.1−0.5), Lewis number (0.1−10), bouncy ratio (1−3), Hartmann number (0−80), Soret number (0.1−0.5) and Dufour number (0.1−0.5) while Prandtl number has kept constant at 6.2. The main findings have stated that decreasing Darcy number from 0.1 to 0.0001 leads to a reduction in average values of Nusselt and Sherwood by 31 % (from 5.9449 to 4.7883) and 30 % (from 2.4538 to 1.7162) respectively, at Ra=105. Also, mass and heat transfer both increase with the increase of the Ra number where both values of Nusselt and Sherwood increase by approximately 80 % (Nuav from 3.2612 to 5.8939) and 100 % (Shav from 1.2109 to 2.4246) respectively, by increasing Ra from 103 to 105 at ϕ=0.01. In contrast, the increase of the fusion temperature from 0.1 to 0.9 has a less pronounced effect on heat and mass transfer, with variations of up to 6 % for Nuav and 5 % for Shav, but it dramatically influences the melting solidification region location. Furthermore, the presence of magnetohydrodynamics negatively influences the mass and heat transfer, with increases in Hartmann number from 5 to 80 resulting in decreases of up to 26 % in Nuav (from 3.4898 to 3.2627) and 35 % in Shav (from 1.3681 to 1.2132) at Ra=104. © 2024

This study investigates the effects of Nano-Encapsulated Phase Change Materials (NEPCMs) on double diffusive free convection in a partially porous cavity, considering Soret-Dufour effects and magnetohydrodynamics. The problem is modeled using non-dimensional governing equations, solved numerically through a Galerkin finite element method. The research examines the influence of key parameters including Rayleigh number (Ra: 103–105), Darcy number (Da: 10–4 -10–1), Hartmann number (Ha:0−80), NEPCM volume fraction (ϕ:0−0.04), Lewis number (Le:0.1−10), fusion temperature (θf:0.1−0.9), and Stefan number (Ste:0.1−0.9) on heat and mass transfer characteristics and entropy generation. Results show that increasing Ra significantly enhances heat and mass transfer, with Nusselt and Sherwood numbers rising by 424.8 % and 547.3 % respectively as Ra increases from 103 to 105. Higher Da and ϕ improve heat transfer, while stronger magnetic fields suppress both heat and mass transfer. An optimal fusion temperature (θf=0.5) is identified for maximum heat transfer enhancement. Total entropy generation, considering thermal diffusion, nanofluid friction, magnetic effects, porous medium, and mass diffusion contributions, increases by 15,957 % with Ra and decreases by 42.5 % with increasing Ha. The Bejan number analysis reveals that non-thermal irreversibilities become increasingly dominant at higher Ra and Ha values. The study concludes that NEPCMs can effectively enhance heat transfer in partially porous cavities, with their performance strongly influenced by Ra, Da, and Ha. The findings provide valuable insights for optimizing thermal management systems incorporating NEPCMs, particularly in applications involving porous media and magnetic fields. © 2024 The Author(s)

This study investigates the convection flow of nano-encapsulated phase change material (NEPCM)-water mixture in an evacuated tube solar collector manifold, focusing on the effects of magnetohydrodynamic (MHD) double-diffusive convection and exothermic reaction. Computational fluid dynamics simulations using the Galerkin finite element method were employed to analyze temperature and concentration distributions, fluid flow, melting zone of PCM nanocapsules, Nusselt number, Sherwood number, entropy generation, and thermal performance. The numerical analysis considers a range of dimensionless parameters, including Rayleigh number (Ra=103−105), Lewis number (Le=0.1−10), buoyancy ratio (Nz=1−5), nanoparticle concentration (ϕ=0.01−0.035), fusion temperature (ϴf=0.1−0.9), Stefan number (Ste=0.1−0.9), Hartmann number (Ha=0−50), magnetic field inclination angle (γ=0°−90°), and Frank-Kamenetskii number (FK=0−2.5). Results show that increasing Ra enhances the average Nusselt number (Nuav) by up to 156.1 % and the average Sherwood number (Shav) by up to 104.5 %, while increasing the total entropy generation by up to 13,155 %. Increasing FK reduces Nuav by up to 42.2 % but increases Shav by up to 13.1 %. The Lewis number and buoyancy ratio significantly influence the hydrothermal performance, with Nuav exhibiting non-monotonic behavior and Shav increasing by up to 240.9 % as Le increases. The nanoparticle concentration enhances Nuav by up to 49.7 %. Interestingly, the magnetic field effects are less pronounced than in previous studies, with Ha having a minor impact on Nuav and Shav. These findings have significant implications for the design and optimization of evacuated tube solar collectors and other thermal energy storage systems, potentially leading to improved efficiency and performance in real-world applications. © 2024 Elsevier Ltd

Unsteady study of the natural convection of aluminum oxide-water nanofluid within a trapezoidal geometry containing a circular cylinder located at its center. Finite Element method has been considered for the numerical analysis. The proposed investigation handled the impact of Rayleigh number (103–105), chemical reaction parameter (0–4), aluminum oxide nanoparticles volume fraction (0–0.06), magnetic field (0–63) and its inclination angle (0°–90°), and circular obstacle diameter (0.3–0.7) effects on time-dependent natural convection of Al2O3–H2O nanofluid. On the other hand, the value of Prandtl number has kept constant at (Pr = 6.2). Since the nanofluid mobility at φ = 0.02, Ha = 3, and Fk = 1 significantly improved, the heat transfer rate achieved its maximum intensity at Ra = 105. Research also reveals a little effect on heat transfer by increasing the fraction of nanoparticles. Additionally, as Ha intensifies from 0 to 63, a final change in the mean Nusselt number of 28.65 % is displayed. Finally, as the magnetic field angle of rotation is diminished, more enhancement in heat transmission is achieved. This research provides insights into the intricate relationship between natural convection and exothermic reaction under the influences of various conditions. This can illustrate the flow and thermal behaviors of nanofluid in such non-uniform shapes in many engineering applications. © 2024

This description focuses on how the magnetic field affects mass and heat transfer in a hybrid nanofluid (Hnf) between two parallel, rotating plates. By dispersing aluminum oxide (Al2O3) and molybdenum disulfide (MoS2) nanoparticles (NPs) in ethylene glycol (EG), a hybrid nanofluid (Hnf) is created. This research aims to analyze the heat and mass transfer characteristics in the flow of a hybrid nanofluid (MoS2-Al2O3/EG) between two rotating parallel plates under the influence of a magnetic field. Furthermore, the statistical technique of response surface methodology (RSM) has been employed to optimize the parameters of velocity, temperature, and concentration of the nanofluid within the flow region bounded by the rotating plates. Dimensionless differential equations have been calculated and checked using the Homotopy perturbation method. This study introduces a novel approach by utilizing the RSM method to identify optimal points for velocity and temperature parameters of nanofluids between two stretching plates for the first time. Additionally, the article innovatively applies the exact HPM method to validate dimensionless linear and non-linear coupling equations. As the Reynolds number and the suction/injection coefficient of nanofluids flowing between two plates under tension increase, the results indicate a decrease in the velocity field. This decrease in velocity field can be attributed to the reduction in fluid diffusion as viscous forces diminish with varying Reynolds numbers. The ideal temperature distribution for nanofluids flowing between two parallel plates occurs when they are uniformly dispersed at the midpoint between them. As the distance from the initial point of nanofluid entry to the end of the plates increases, along with the vertical distance from the bottom plate, the temperature gradient diminishes, reducing the thickness of the thermal boundary layer. The velocity gradient and the rate of heat flux transfer between the nanofluid and plate rise by 34 % when the volume percentage is raised from 1 % to 5 %. © 2024 The Author(s)

Mixed convection convection is a vital subject and it is beneficial in many engineering applications. The current paper addresses this subject with a novel geometry and very vital variables including magnetohydrodynamic influences on the forced/free convection as well as the reproduction of irreversibilities in an enclosure filled with water/carbon nanotubes (CNT) and a nonadiabatic cylinder. The top wall is split from the middle and moves in different directions to drive the isotherms which are generated from the bottom wall and cold from the vertical surfaces. The numerical analysis was carried out using finite element method; the variables are Reynolds number (40–200), Richardson number (0.01–10), Hartmann number (0–62), inclined magnetohydrodynamic angle (0–60), volume concentration (0–0.08) while Prandtl number has kept constant at 6.2. The results show that the transformation of heat, as well as the fluid flow, are largely influenced by the change of variables, where increasing Reynolds number, Richardson number enhances heat and increases the flow circulation. Furthermore, heat transfer enhances by 57 % when increasing Ri from 0.1 to 10 at Re=41 and this enhancement increases to 62.5 % at Re = 200. Furthermore, increasing the concentration of the carbon nanotube can cause heat transfer but decrease the circulation of the fluid. In contrast, the transfer of heat as well as the flow streams are remarkably decreased with the increase of the Hartmann at zero inclination angle; however, the value of the Nusselt average increases with the increase of the inclination angle. Moreover, the value of Nusselt average decreses by 34.7 % when increasing Ha from 0 to 62 at Re = 200. Furthermore, the total entropy generation increases as Richardson number, Reynolds number, and volume concentration increase; in contrast, detraction with the rise of the MHD. © 2024

Fatigue properties play a crucial role as they are vital to ensuring the durability and integrity of components subjected to repeated loading conditions over long periods. The main objective of this work is to investigate the fatigue behavior of dual-phase low-carbon steels used in automotive applications using a rotating bending fatigue machine. Heat treatments were carried out to analyze the microstructure's effect on the fatigue properties, including quenching low-carbon steel samples at 800 °C and 900 °C. Hardness and tensile tests were performed, and the microstructure was inspected to examine the constitute phases. With the assistance of a scanning electron microscope, fractographic analyses were carried out to reveal the fracture features of the samples at different lifetime ranges. The results show that various failure mechanisms occur depending on the stress levels. Additionally, the specimens quenched at 900 °C exhibited higher fatigue strength. © 2024

In anti-lock brake systems (ABS), the primary goal of the controller is to maximize vehicle deceleration by maintaining the slip ratio at an optimal level. This work presents a fresh approach that enhances ABS performance by integrating a sliding mode controller with a barrier function. This method combines integral sliding mode control with adaptive laws informed by barrier functions, effectively managing external disturbances and uncertainties in inertia. A significant benefit of this approach is that it does not require prior knowledge of the upper limits of these uncertainties and disturbances, thanks to the barrier function-based sliding mode control. The system state is initially aligned with the switching manifold, ensuring robust compensation for any uncertainties and disturbances right from the start of braking. During the sliding mode phase, dynamic properties are finely tuned to ensure that the system's performance remains consistent. The effectiveness and reliability of the proposed controller have been demonstrated through numerical simulations conducted in MATLAB/Simulink, proving its capability across a range of road conditions. © 2024 the author(s), published by De Gruyter.

This paper delves into the numerical investigation of aluminum oxide–water nanofluid thermal and dynamic performances under the influences of magnetic field application and chemical reaction, utilizing the Finite Element Method within a circular enclosure containing three inner tubes, as an application to the heat exchanging phenomenon between the reactive shell of the cavity and the surface of the triple tubes. Various governing parameters were studied for their interaction on the nanofluid flow and heat transmission rate within the proposed geometry, including the Rayleigh parameter (103≤Ra≤105), Hartmann parameter (0≤Ha≤61), nanoparticles concentration (0≤∅≤6×10-2), magnetic rotational angle (0o≤γ≤90o), and Frank-Kamenetskii parameter (0≤Fk≤3). The results indicated that raising Ra from 103 to 105 results in expediting the nanofluid velocity by 10.62 % and 100 % respectively as well as raising the total heat transfer efficiency. The nanofluid speed was also increased by 28.57 % when Fk has to further increase to a value of 3. When there was no exothermic activity present, the rate of heat transmission was at its lowest, and it was greater when the Fk value was 3. Similarly, there were discernible impacts in various areas of the geometry as the Ha number intensified and the Nuavg decreased. Improvements in local and mean Nusselt parameters are observed when the concentration of nanoparticles is increased, suggesting better heat transfer, achieving an increase by 7 % in the average Nusselt number. This research emphasizes the importance of nanoparticle concentration in raising the medium's rates of heat transmission, contributing to advancements in energy storage development. © 2024 The Author(s)

In this paper, magnetohydrodynamics of a Casson fluid flow is inspected with the presence of thermal radiation and chemical reaction. Employing the perturbation procedure, the modeling equations are tenacious; the graphs are acquired to illustrate the results. The Casson fluid velocity increases as the perturbation parameter increases. Grashof values for heat and mass transport enhanced Casson fluid velocity. Increasing Casson, magnetic, heat source, and radiation parameters reduce the flow velocity. Prandtl number, heat source, and radiation parameter all reduced the temperature profiles. Chemical reaction parameters lowered the concentration profiles. The skin friction enhances with Casson parameter impact. However, the skin-friction coefficient, Sherwood and Nusselt numbers reduce with an increment in the perturbation parameter. In certain cases, this study’s answers agreed well with the previous literature. Casson liquid with a magnetic region using mixed convection by an exponential vertical boundary layer is the novelty of the work. © World Scientific Publishing Company.

In this paper, the integral sliding mode control (ISMC) with non-standard backstepping is utilized for designing an automotive active suspension system hydraulic actuator. The main objective of this design is to make the suspension system’s ride more comfortable while keeping the road holding and rattling space within safe bounded limits. The controller design consists of applying the ISMC to perform a virtual control force, that meets all suspension requirements, besides utilizing a hydraulic model by a non-standard backstepping control algorithm taking into consideration the uncertainty and nonlinearity of the hydraulic system. The main advantage of ISMC is to have a robust controller, such that the stability of the system appears from starting its states at the switching surface where system nonlinearity, parameter changes, and road disturbances are rejected by a discontinuous control term present strongly in the suspension dynamics. This work demonstrates the effectiveness of the present controller design through the simulation of a 2-DOF quarter car system equipped with a passive suspension. The results vividly showcase how the current design enhances the overall performance of the system. © 2023, KSAE.

This work synthesized a thermoplastic polymer with varying densities along one direction using additive manufacturing technology to study the dynamic and static characteristics of functionally graded viscoelastic materials (FGVMs). To describe the mechanical properties of FGVMs, an analytical formulation based on the sigmoid-law formulation was proposed. The experimental program is conducted on 3D-printed samples, and various tests are conducted to examine the performance of such materials. Furthermore, the finite element method was used to evaluate the structural system’s flexural properties. The influences of FG parameters and geometrical properties on flexural and reverse bending fatigue life are analyzed in detail. The results show that increasing porosity from 10% to 30% at a power-law index (k = 2) reduces bending strength by 31.25 percent and deflection by around 11.2 percent for VE samples. Changing the power-law exponent from 0.5 to 10 increases fatigue strength by 35 %. © Authors 2023.

The hybrid combustor is represented by combined between premixed and diffusion flame. The premixed flame implemented by cylindrical burner which it gives swirling flow by two nozzles in opposite direction. The diffusion flame investigated by co-axial jet of fuel and annulled by air. The hybrid flame was experimentally and numerically investigated to get high level of flame stability and low emissions level of pollutant. This research used working fuel of liquid petroleum gas which it has 40% propane and 60% butane. Two types of flame were examined, diffusion flame combustion DFC and hybrid flame combustion HFC. In HFC, the influences of fuel nozzle geometry on air/fuel mixing were achieved in terms of stability of flame and level of pollutant emissions. An extremely stability of flame can be given in HFC by the swirling premixed which utilized it as a flame holder because it created over all inner surface of burner. The results showed that the burner design gave high vortex flow by evaluating swirl number for hybrid flame in term of heat input and overall equivalent ratio. The results of flame temperature for three types of combustion premixed flame combustion PFC, DFC and HFC with lean, rich and stoichiometric of equivalence ratio. Numerically studded temperature distribution of diffusion flame combustion by simulate cyclone burner which using in experimental work. Fluent Ansys 16.1 used for 2D simulate turbulent modeling (Standard k-ε model). Three cases of mixture investigated numerically lean, rich and stoichiometric and compared it with experimental rustles. The temperature observed numerically is more than which observed experimentally because the enhancement in heat transfer through test rig burner and low mixing efficiency between air and fuel. © 2023, Mathematical Modelling of Engineering Problems. All Rights Reserved.

The world's interest in energy and as a result of the urgent importance of that, researchers focused on the development of heat transfer to have a significant impact on the consumption of that energy. Where we note the great interest by researchers in developing heat transfer and using the best possible methods to improve heat transfer. In this literary review, a large group of research has been carried out to find out the importance of heat transfer and the methods used by researchers to develop heat transfer. Porous materials, nanomaterials and fins were used in the development of heat transfer. Where we note the importance of adding these materials (porous materials, nanomaterials and fins) to the original materials contribute significantly and clearly to improving heat transfer and this has a significant impact on energy consumption or trying to dissipate it, as we note the clear difference when using the original materials without adding these materials as the heat transfer is less and it consumes more time. Researchers can focus on the importance of improving heat transfer for its importance in many applications that have a direct impact on human life. © 2022 International Information and Engineering Technology Association. All rights reserved.

Diesel engine characteristics were investigated experimentally while adding different concentrations of third generation biodiesel spirulina algae methyl ester (SAME). Three volumetric blends of SAME are added to standard Iraqi diesel, namely 10% SAME, 20% SAME, and 30% SAME. The properties of the fuels were found according to the American Society for Testing and Materials standards (ASTM). Experimental work was conducted on a single-cylinder diesel engine under variable load and compression ratio. Three compression ratios are used, starting from 14.5, 15.5, and 16.5. Based on the results obtained, the presence of SAME along with diesel caused an increase in Brake specific fuel consumption (BSFC), carbon dioxide (CO2), and nitrogen oxides (NOx) while decreasing both brake thermal efficiency (BTE) and exhaust gas temperature (EGT). Hydrocarbon (HC) emissions decreased by 7.14%, 8.57%, and 10.71%, for 10% SAME, 20% SAME, and 30% SAME, respectively, compared to the original neat diesel fuel. The dramatic carbon monoxide (CO) emission reduction was at full load point. The addition of SAME from (10 to 30)% reported a decrease in CO by (6.67–20)%. NOx, as well as CO2 emission, are increased as a result of SAME addition. The compression ratio change from (14.5/1 to 16.5/1) led to increased BTE, NOx, and decreased BSFC and all carbon emissions. The experimental results are validated with other studies' findings, and minor divergence is reported. © 2022, The Author(s).

The double-diffusive mixed convection of MWCNT/water in a curvilinear cavity with split lid-driven and hot ellipses has been numerically studied in this paper. The top wall is split to move in different directions. The inclined walls, as well as the top wall, are cold with low concentration. Furthermore, the inner ellipses represent the heat source and high concentration, while the vertical and bottom walls are adiabatic. The considered variables are a range of Reynolds (50 ≤ Re ≤ 200), Richardson (0.1 ≤ Ri ≤10), Hartmann (0 ≤ Ha ≤ 30), Lewis (0.1 ≤ Le ≤ 10), bouncy ratio (−6 ≤ N ≤ 6), volume fraction (0 ≤ ϕ ≤ 0.08) and the direction of the split lid-driven at constant Prandtl (Pr = 6.2). The analysis has been done using the finite element method. The main results stated that the heat and mass transfers are greatly enhanced with the increase of Re number in the case of low Ri number, where Ri = 0.1 and Re = 50, the values of Nuavg and Shavg are equal to 7.4 and 10.7 and become 10.7 and 16.2 at Ri = 0.1, Re = 200 respectively. However, the effect of the Re becomes unnoticeable with a high Ri. Furthermore, Le has a positive effect on heat and mass transfer, and this effect increases with increasing Ri. For example, at Ri = 10 and Le = 1, Nuavg is 2.1 and Shavg is 2.2, whereas at Ri = 10 and Le = 10, Nuavg is 3.1 and Shavg is 4.6. © 2022

Due to its engineering uses in recent years, natural convection within cavities has been studied to enhance heat transfer in various package shapes by infusing the base fluid with nanoparticles. In this paper, we examined natural convection in a square cavity with an inclined roof of Ag-water nanofluid and internal bodies (circular and elliptical cylinders) at the enclosure's center. The (top, bottom, and circular cylinder) walls are assumed to be adiabatic, whereas the (ellipse cylinders and left sidewall) are warmed and the right sidewall is maintained cool. The COMSOL program is based on the "Galerkin finite element approach" in terms of numerical computations. The "Rayleigh number" (Ra) (103- 106) is utilized, as is the solid volume fraction (0.05), the angle of inclination (-45°, -30°, 0°, 30°, 45°), "the inner circular cylinder radius considered as (R=0.15)" and "the radius of the inner ellipse cylinder as (Rx=0.2 & Ry=0.15). At a high "Rayleigh number", the stream function has the lowest value when the caustic angle is tilted to (-30°). While it comes in second place, the angle of inclination (0°) gets the highest value. While at a low "Rayleigh number", there is no effect of the angle of the stream function. There was also a convergence in Nusselt numbers at any angle at the hot left wall, at 30° and 45°, and in the hot ellipse, at 60° and 90°, so we looked at them all. © 2022 International Information and Engineering Technology Association. All rights reserved.

Two thermal cylinders with varied shapes (circular (R = 0.15), square (L = 0.15), ellipse (Rx = 0.2, Ry = 0.15), and circular (R = 0.15) near the cold wall of the square enclosure where the (AR = 0.7) is explored numerically in the present study. The nanofluid is contained within the cavity (Al2O3). Left-side vertical wall and inner bodies are maintained at a fixed temperature (Th), while the right-side vertical wall is maintained at a cool temperature (Tc). Thermal insulation is used to insulate the upper and lower horizontal walls. This code is used the (technique of finite elements), which is utilized to resolve dimensionless equations in the COMSOL program. The basic parameters that were utilized in this paper where: the Rayleigh number (Ra), which ranged from 103 to 106; the percentage of solid volume (φ=0.06); and the aspect ratio (AR =0.7). The outcome demonstrates that: When the heated internal bodies are used in different forms, the effect of fluid movement will be different, and when the two inner bodies are combined, the highest stream function of up to 33 can be obtained. The isotherm line shows the clear and important effect of internal bodies in enhancing and improving heat transfer. For the two-square case, the average Nu was at its lowest point. While the highest Nu was for two – the ellipse case followed by the cylinder – the ellipse and the two circular cylinders © 2022, Journal of Advanced Research in Fluid Mechanics and Thermal Sciences.All Rights Reserved.