Heat Transfer最新文献

{"title":"Experimental and Numerical Study of Optimization of Perforated Ribs Geometry and Configuration Using Taguchi Approach","authors":"Mohsen Babamir,&nbsp;Mohammad Ansari,&nbsp;Majid Bazargan","doi":"10.1002/htj.23339","DOIUrl":"https://doi.org/10.1002/htj.23339","url":null,"abstract":"<div>\u0000 \u0000 <p>The present experimental and computational investigation considers the optimization of solar air heaters (SAHs) with perforated ribs to simultaneously enhance the Nusselt number (<i>Nu</i>) and minimize pressure losses. This study introduces a novel approach by utilizing the Taguchi method to optimize geometric parameters, enabling efficient evaluation of heat transfer and pressure drop interplay for improved solar air heater performance. The effects of relative rib height (<i>e</i>/<i>D</i>), rib pitch (<i>p</i>/<i>e</i>), perforation diameter (<i>d</i>/<i>e</i>), and the number of perforations (<i>n</i>) were investigated using the finite volume method. A three-dimensional, steady-state, symmetric, and turbulent flow based on the <i>k</i>−<i>ω</i> SST turbulence model was employed, with optimization conducted using the Taguchi method. The analysis was performed at a Reynolds number (<i>Re</i>) of 18,000. The complex influence of perforation geometry on heat transfer and flow characteristics underscores the challenge of balancing performance parameters. Larger perforation diameters and optimized rib spacing reduced pressure drops by weakening recirculation zones and promoting uniform flow, while also enhancing local heat transfer. The optimal configuration (<i>e</i>/<i>D</i> = 0.11, <i>p</i>/<i>e</i> = 20, <i>d/e</i> = 0.7, <i>n</i> = 2) achieved a 41% improvement in thermal-hydraulic performance. Increasing the perforation size (<i>d</i>/<i>e</i>) improved heat transfer up to a threshold of <i>d</i>/<i>e</i> = 0.7. Beyond this point, the turbulence intensity decreases and improvement in heat transfer ceases. The findings provide a practical framework for designing energy-efficient SAHs by systematically evaluating geometric parameters and offer new insights into balancing heat transfer and pressure loss, contributing to advancements in renewable energy and thermal management.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3247-3265"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Numerical Investigation of the Impact of Converging/Diverging Curved Channel Configuration on the Multi-Channel Cold Plate Hydrothermal Performance","authors":"Zainab Muwaffaq Saleh,&nbsp;Hayder Mohammad Jaffal","doi":"10.1002/htj.23355","DOIUrl":"https://doi.org/10.1002/htj.23355","url":null,"abstract":"<div>\u0000 \u0000 <p>With the advancement of modern electronics and the increase in thermal power density, heat management has become a challenge that impacts device performance. Cold plates are an effective solution in liquid cooling systems, improving heat dissipation and thermal stability. This study presents a numerical evaluation of multichannel cold plates' thermal and hydraulic performance to enhance their overall efficiency. Geometric modifications included dual ports for improved flow distribution, heat transfer, and channel structure changes, such as straight, convergent, divergent, and convergent/divergent configurations. Performance was assessed through temperature distribution, pressure drop, and cooling efficiency analysis using ANSYS Fluent 22R1 under incompressible laminar flow conditions with water mass flow rates between 0.002 and 0.006 kg/s. Compared with the performance of a conventional multi-mini-channel cold plate (CMMCP), the results of this study showed that the flow-splitting effect at the outlet significantly improved thermal performance compared with a single outlet. Using one inlet and two outlets achieved higher performance for the cold plate compared with a CMMCP, reducing pressure loss by 61% and improving the Nusselt number by 14.4%. Furthermore, modifying the convergent curve of the central channel had a greater impact on the Nusselt number than modifying the divergent–convergent curve. Narrowing the central channel increased the Nusselt number by 48.71% compared with the conventional design, while also significantly reducing the plate temperature. The double-outlet, convergent-curved channel design performed best overall performance, achieving the highest cooling and fluid flow rates, with an overall performance of 1.81.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3298-3311"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256551","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oscillatory Magnetohydrodynamic Heat Transfer in Viscous Blood Flow Through the Porous Capillary","authors":"Anju Saini,&nbsp; Sarita","doi":"10.1002/htj.23357","DOIUrl":"https://doi.org/10.1002/htj.23357","url":null,"abstract":"<div>\u0000 \u0000 <p>In this study, we have examined the oscillatory magnetohydrodynamic Poiseuille flow of viscous blood in a permeable capillary, considering temperature-dependent viscosity and oscillating pressure gradient. In this updated study, the Brinkman and energy equations were used and solved by Galerkin's finite element method to investigate the effects of some parameters, such as the suction/injection parameter, the Darcy number, the Prandtl number, and time. The outcomes suggest that more suction increases the blood speed, while injection decreases it. In this case, the blood temperature and velocity are decreased with a higher Prandtl number. The volumetric flow rate is proportional to the Prandtl number but inversely proportional to suction/injection. In addition, the Nusselt number has an opposite relationship over time -suction/injection and contrast of the Prandtl number. These insights provide an advanced understanding of blood flow behavior in biodynamic applications, including modeling, hyperthermia, and hemodynamic regulation.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3323-3331"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat Transfer and Natural Convection in an Internally Heated Porous Box Container With Variable Gravity Field","authors":"Amit Mahajan,&nbsp;Madhvi Raj","doi":"10.1002/htj.23354","DOIUrl":"https://doi.org/10.1002/htj.23354","url":null,"abstract":"<div>\u0000 \u0000 <p>The study focuses on convection within a fluid-saturated porous medium, which is internally heated, with a gravitational field that changes with height across the enclosure. Four distinct configurations of gravity variation and constant volumetric internal heating are selected, and their impact on the onset of convection is analyzed across four different models. The primary aim is to examine the influence of key parameters such as the Rayleigh numbers 60, 70, 80, 100, 105, and 110, with the gravity parameter ranging from 0 to 0.06 and the internal heat parameter between 0.1 and 0.4, on the dimensionless time concerning temperature and heat transfer. The formulated differential equation is numerically solved using the Galerkin method. MATLAB's built-in solver, ode45, is used for numerical simulations to evaluate the heat transfer rate and generate two- and three-dimensional isotherms for multidimensional models under varying gravitational fields, showing the novelty of our solutions. These key parameters elevate the Nusselt number, signaling enhanced heat transfer and facilitating convection by destabilizing the system. The oscillations needed for the Nusselt number to stabilize are fewer in the vertical enclosure than in other configurations across varying gravity parameters, internal heat parameters, and Rayleigh numbers. This analysis is relevant to heat transfer and material processing applications.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3278-3297"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Thermo-Hydraulic Performance in Heat Exchanger Tube Equipped With Coil Strip Metal Foam Inserts","authors":"Ayser Muneer Flayh","doi":"10.1002/htj.23356","DOIUrl":"https://doi.org/10.1002/htj.23356","url":null,"abstract":"<div>\u0000 \u0000 <p>This article proposes a novel experimental comparison of the thermo-hydraulic of coiled-strip inserts for two types: copper foam coil-strip inserts (CFCSI) made of open-cell copper foam, and coiled-strip inserts (CSI) made of aluminum within a heat-tube in turbulent flow (4000–30,000). The newly designed CFCSI aims to improve the elevated thermal performance factor (TPF) above that of CSI in similar circumstances. The CFCSI and CSI used were with three-pitch lengths of (<i>P</i> = 15, 20, and 25 mm). The interesting detection in the situation of tubes equipped with CFCSI in the novel arrangement was that the secondary vortices' strength manifested a periodic variation from weak to strong lengthwise in the mainstream direction, which introduced a rise in the TPF. Also, the results elucidated that the heat transfer was improved (Nusselt number, Nu) for the CFCSI and CSI models, and this improvement decreases with increasing pitch length, but the CFCSI showed a higher heat transmission rate compared to the CSI and plain tube. The Nu of CFCSI averaged about (432%–384%) compared to the CSI, depending on the pitch length, and about (130%–108%) over that of the clear tube of the CSI. The suggested CFCSI has a TPF of 1.61–1.5 at 4000 Reynolds number (Re) and 15 mm pitch length, which is considered greater than CSI and plain tubes.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3312-3322"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Semi-Analytical Solution of Thermoacoustic Heat Transfer in a Pulse Tube in the Presence of Pulsating Internal Heat Source","authors":"Fatemeh Sobhnamayan,&nbsp;Faramarz Sarhaddi,&nbsp;Amin Behzadmehr","doi":"10.1002/htj.23345","DOIUrl":"https://doi.org/10.1002/htj.23345","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper, thermoacoustic flow and heat transfer in a pulse tube are investigated. The driving force of thermoacoustic flow is a pulsating internal heat source. The governing equations for the problem include continuity, momentum, energy, and the ideal gas law. The governing equations are solved semi-analytically by considering the decomposition of a main flow and a two-dimensional oscillating flow with variable thermophysical properties. The semi-analytical solution method is the Leibniz-Maclaurin power series method. The semi-analytical solution of the present study is in good agreement with the analytical solution of previous studies. The results show that there is a maximum point for pressure and an inflection point for velocity. The locations of these points are around the middle of the pulse tube length. Increasing the internal heat source increases the pressure and temperature and reduces the density. Fluid friction losses reduce the gain of work flux density and radial velocity gradients increase the gain fluctuations. The results of the present research can be considered as an augment heat transfer tool to improve the performance of pulse tube engines, pulsating heat pipes, electronic device coolers, and so on.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3266-3277"},"PeriodicalIF":2.8,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Entropy Generation and Heat Transfer Analysis of the Hydromagnetic Flow of Three Distinct Viscoelastic Fluids Over a Cone With Soret and Dufour Effects via Machine Learning","authors":"S. Varshegaa,&nbsp;P. Francis,&nbsp;P. Sambath,&nbsp;N. Ameer Ahammad,&nbsp;H. Thameem Basha","doi":"10.1002/htj.23328","DOIUrl":"https://doi.org/10.1002/htj.23328","url":null,"abstract":"<div>\u0000 \u0000 <p>Efficient heat and mass transfer is crucial in fields like energy systems and chemical processes, especially when dealing with non-Newtonian fluids, such as Casson, Maxwell, and Williamson. However, the interactions of thermal radiation, Soret, and Dufour effects in magnetohydrodynamic free convection over a vertical cone have not been thoroughly studied, nor has the impact of entropy generation on thermodynamic efficiency. This study aims to explore these interactions, focusing on how they affect heat and mass transfer and entropy generation in three types of non-Newtonian fluids. The governing equations are converted into dimensionless forms and solved using MATLAB's BVP4C solver, with results verified using an artificial neural network model. The main findings indicate that the Casson fluid has better heat transfer characteristics due to its lower viscosity at high shear rates. It was also found that magnetic fields can decrease velocity but increase the thermal and concentration boundary layers, which enhances diffusion rates. Additionally, thermal radiation, Soret, and Dufour effects significantly improve heat and mass diffusion, and the analysis of entropy generation highlights their importance for system efficiency. By combining numerical methods with machine learning, this study provides useful insights for improving heat and mass transfer in energy systems, chemical reactors, and manufacturing processes that use non-Newtonian fluids.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3220-3246"},"PeriodicalIF":2.8,"publicationDate":"2025-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Nonlinear Thermal Density Variation and Radiation on MHD Mixed Convection Through a Porous Medium Over a Permeable Vertical Plate: A Numerical Approach","authors":"Bhaskar Jyoti Dutta,&nbsp;Bhaskar Kalita","doi":"10.1002/htj.23341","DOIUrl":"https://doi.org/10.1002/htj.23341","url":null,"abstract":"<div>\u0000 \u0000 <p>In the present paper, we study the effect of nonlinear thermal radiation on magnetohydrodynamic (MHD) flow through a porous medium subject to a convective boundary condition over a permeable vertical plate. The Boussinesq approximation is used to predict nonlinear density variation with temperature (NDT), which enhances thermal transport. Similarity transformations facilitate the conversion of the governing nonlinear partial differential equations into nonlinear ordinary differential equations, enabling further analysis. The solutions are obtained and presented graphically using the bvp4c method in MATLAB. The primary objective of our study is to analyze the effects of suction/injection, NDT, and nonlinear thermal radiation on MHD flow dynamics and temperature distribution. The conclusions reveal that the nonlinear Boussinesq approximation parameter and Grashof number enhance buoyancy forces, increasing velocity boundary layer thickness and improving heat dissipation. Higher nonlinear thermal radiation raises fluid temperature, reduces viscosity, and thickens both boundary layers. Suction enhances flow stability by thinning boundary layers and facilitating efficient heat transfer, whereas strong injection increases the boundary layer thickness, retains heat, and disrupts flow stability. A higher magnetic parameter slows velocity more in suction and thickens the thermal boundary layer in injection. A greater Prandtl number reduces boundary layer thickness and enhances the Nusselt number, while a higher convective heat transfer parameter increases both boundary layer thickness and skin friction in suction. We have compared our numerical results with those of previous studies and observed an excellent agreement. The novelty of this study lies in its unique approach to modeling nonlinear thermal radiation, suction/injection, and its impact on MHD flow and heat transfer in porous media. The findings have practical implications for various engineering fields, including energy systems, aerospace, biomedical engineering, chemical processing, and environmental engineering, contributing to the optimization of heat transfer in technological applications.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3163-3178"},"PeriodicalIF":2.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Role of Stretching/Shrinking on the Heat Transfer Performance of Fully Wetted Trapezoidal Fin Structures Under the Impact of Convection and Radiation Effects","authors":"Toremavinahalli Mallikarjunaiha Swetha,&nbsp;Bijjanal Jayanna Gireesha,&nbsp;Puttaswamy Venkatesh","doi":"10.1002/htj.23348","DOIUrl":"https://doi.org/10.1002/htj.23348","url":null,"abstract":"<div>\u0000 \u0000 <p>The trapezoidal shape maximizes surface area, promoting efficient heat dissipation and transfer in diverse sectors, contributing to improved thermal performance and preventing overheating in various devices and systems. In this context, the present work focuses on the thermal performance and features of heat transmission through a fully wetted trapezoidal fin structure, when the fins' surface is equipped with a shrinking or stretching mechanism. The trapezoidal fin has been analyzed using three distinct mechanisms: stretching, stagnation, and shrinking mechanisms. Furthermore, the formulation of the fin performance problem incorporates the effects of convection, radiation, and internal heat generation. To examine the solid–fluid interactions, Darcy's law has been applied. The governing equation has been nondimensionalized by employing appropriate nondimensional terms, and then solved by using Runge-Kutta-Fehlberg (RKF) method numerically. The significance of essential parameters such as internal heat generation, convection, radiation, wet porous parameter, stretching/shrinking parameter, and other relevant parameters and efficiency of trapezoidal fin have been analyzed and graphically interpreted. We observed that as the peclet number (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <mi>Pe</mi>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math>) increases by 400%, temperature also increases by 7.46%. By enhancing the value of radiation parameter <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <mi>Nr</mi>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math> by 900%, the temperature of the fin tip decreases by 27.306%. It is inferred that the shrinking mechanism greatly enhances the fin's cooling impact, particularly when the fin is moving. The current analysis is helpful for the fin design and pertains to practical applications.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3179-3192"},"PeriodicalIF":2.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Investigations of the Aerothermal Performance of Modern Turbine Blade Tip Geometries at Design and Off-Design Conditions and Under Stationary and Moving Shroud","authors":"Kheir-Eddine Arrif,&nbsp;Zakaria Mansouri,&nbsp;Salaheddine Azzouz","doi":"10.1002/htj.23352","DOIUrl":"https://doi.org/10.1002/htj.23352","url":null,"abstract":"<p>High-pressure turbine blade tips operate under extreme thermal stress, generating significant aerodynamic losses that must be continually optimized to improve engine efficiency and durability. This study uses computational fluid dynamics (CFD) to investigate the aerodynamic and thermal behavior of advanced turbine blade tip configurations, specifically GE's vertical and inclined shelf tips, under both design and off-design transonic conditions. Conventional designs, such as flat and squealer tips, were also analyzed for comparison. Shroud motion effects were included to simulate turbine stage rotation. The simulations are performed by solving the three-dimensional, steady and turbulent form of the Reynolds-Averaged Navier-Stokes (RANS) equations using the Ansys-CFX. A two-equation turbulence model, Shear stress transport (SST) with Gamma-Theta transition formulation is used. CFD results showed strong alignment with experimental data, validated through isentropic Mach number and heat flux measurements. The results revealed that cavity-based designs (squealer and shelf tips) exhibited complex secondary flow structures within the tip cavity, including the formation of suction-side and pressure-side cavity vortices (SSCV and PSCV), which contribute to the tip leakage vortex (TLV) and associated aerodynamic losses. The vertical shelf tip demonstrated the lowest leakage rate in both stationary and moving conditions, attributed to its narrow cavity width and reduced PSCV size, while the inclined shelf exhibited the highest heat transfer coefficient (HTC), beneficial for cooling applications but paired with higher leakage and mixing losses. Notably, these findings differ from previous results on GE's shelf tip, where the inclined shelf had the lowest leakage rate.</p>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 5","pages":"3193-3207"},"PeriodicalIF":2.8,"publicationDate":"2025-04-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/htj.23352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144256050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}