Heat Transfer最新文献

{"title":"MHD Flow Past a Temporarily Accelerated Semi-infinite Vertical Plate With Linear Ramped Conditions in Presence of Thermal Diffusion, Thermal Radiation, Chemical Reaction, and Heat Sink","authors":"Nazibuddin Ahmed,&nbsp;Masuma Khanam,&nbsp;Hiren Deka","doi":"10.1002/htj.70015","DOIUrl":"https://doi.org/10.1002/htj.70015","url":null,"abstract":"<div>\u0000 \u0000 <p>This article presents a precise solution to the problem of a transient MHD-free convective chemically reactive flow of an incompressible, electrically conducting, viscous, optically thick, non-Gray fluid past a temporarily accelerated vertically semi-infinite plate with linear ramped conditions where thermal diffusion, thermal radiation, heat sink, and chemical reaction effects are present. Fluid is subjected to a uniform transverse magnetic field of strength <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <msub>\u0000 <mi>B</mi>\u0000 \u0000 <mn>0</mn>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math>. The resulting linear nondimensional governing equations are solved by applying the closed version of the Laplace transform method. To describe the radiation heat flow that appears in the energy equation, the Rosseland model of radiation has been used. Using figures and tables, the impacts of various factors on flow and transport characteristics are studied for both the isothermal and ramped conditions. During the transverse magnetic field's appearance, fluid velocity declines. Viscous force reduces as ramped parameter values increase; hence, we may infer that the fluid's temperature climbs as the viscous force gets higher. There is an improvement in the temperature field with an increase in thermal diffusivity. Increasing mass diffusivity raises the concentration field. As fluid viscosity falls, fluid velocity rises.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4603-4617"},"PeriodicalIF":2.6,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237401","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":"Analytical Investigation on Steady MHD-Free Convection Couette Flow of Heat Generating Fluid Through a Vertical Channel","authors":"Tafida M. Kabir,&nbsp;Shu'aibu Amina","doi":"10.1002/htj.70019","DOIUrl":"https://doi.org/10.1002/htj.70019","url":null,"abstract":"<div>\u0000 \u0000 <p>This study provides an analytical investigation on steady magnetohydrodynamic (MHD)-free convection Couette flow of heat-generating fluid through a vertical channel. The coupled nonlinear differential equations describing the system were solved analytically using Homotopy Perturbation Method. The research examines the influence of various flow parameters, including the Eckert number, magnetic field strength, heat generation/absorption, Prandtl number, and Grashof number. Comprehensive analyses and physical interpretations are presented. The findings showed that fluid velocity and temperature decrease with an increase in magnetic field strength, while higher Eckert numbers led to an increase in both velocity and temperature. Furthermore, the rate of heat transfer decreases at the moving plate but increases at the stationary plate with rising viscous dissipation, magnetic field strength, and Grashof number.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4640-4649"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237292","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 Investigation to Analyze the Effect of Various Operating Parameters on the Thermal Characteristics of Heat Pipe","authors":"Jobin Jose,&nbsp;Puthettu Muraleedharan Sutheesh,&nbsp;Bandaru Rohinikumar,&nbsp;Veershetty Gumptapure,&nbsp;Tapano Kumar Hotta","doi":"10.1002/htj.70023","DOIUrl":"https://doi.org/10.1002/htj.70023","url":null,"abstract":"<div>\u0000 \u0000 <p>The heat pipe is one of the prime candidates in electronic thermal management due to its higher thermal performance and passive nature. The present study aims to develop a 3D mathematical model to simulate the thermal behavior of the heat pipe of length 380 mm under different operating conditions. Steady-state numerical simulations are performed to predict the effect of heat inputs (in the range of 10–50 W), the coolant flow rates (40 LPH, 25 LPH, and 10 LPH), and the coolant inlet temperatures (298.15, 293.15, and 288.15 K) on the heat pipe's thermal characteristics. The analysis reveals that by increasing the heat input from 10 to 50 W, the heat pipe's thermal resistance is reduced by 49.23%, with the same amount of augmentation in its evaporator heat transfer coefficient. The cooling water flow rate also significantly impacted the heat pipe's thermal resistance and heat transfer coefficient. The evaporator heat transfer coefficient decreased by 2.01% at 25 LPH compared to 10 LPH and increased by 1.68% at 40 LPH compared to 25 LPH. Additionally, with the increase in the cooling water inlet temperature from 288.15 K to 293.15 K, the heat pipe's evaporator heat transfer coefficient increased by 7.55%, and thermal resistance was reduced by 6.02%. This confirms the vivid influence of the input thermal energy and cooling water inlet temperature on the heat pipe's thermal characteristics, while the cooling water Reynolds number (flow rate) had a minimal influence on its operating conditions. Hence, this comprehensive analysis of using the heat pipe offers valuable insight for improving heat dissipation and thermal management in electronic devices.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4708-4722"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237298","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":"Enhancing PV/T Thermal Efficiency via Passive Air-Gap Cooling With Stagnant Water Heat Sink","authors":"Moataz M. Abdel-Aziz,&nbsp;Mohammed El Hadi Attia,&nbsp;Abdelkrim Khelifa,&nbsp;Abdallah Bouabidi","doi":"10.1002/htj.70020","DOIUrl":"https://doi.org/10.1002/htj.70020","url":null,"abstract":"<div>\u0000 \u0000 <p>High operating temperatures significantly reduce the efficiency and lifespan of photovoltaic (PV) panels, necessitating innovative cooling solutions. This study investigates a novel passive cooling technique for photovoltaic/thermal (PV/T) systems, integrating moving air through a gap between the PV panel and a stagnant water heat sink. The goal is to enhance thermal management and energy output while minimizing reliance on active cooling mechanisms. Two configurations are compared: a standard PV panel (reference) and an optimized PV/T system with the proposed air-gap cooling design. Key findings demonstrate the effectiveness of the optimized system, achieving a maximum air temperature difference of 22.84 K between inlet and outlet, an average thermal power output of 135.68 W, and a 4.15% increase in electrical power output. The thermal efficiency reached 30.05%, marking an 84.90% improvement over the reference setup. These results highlight the system's ability to maintain lower operational temperatures, thereby boosting both electrical and thermal performance. The innovative aspect of this study lies in its unique passive cooling approach, which combines air movement and stagnant water without requiring external energy input. This addresses a critical gap in PV/T literature by offering a cost-effective, low-maintenance solution for hot climates. The study provides valuable insights for optimizing solar energy systems, contributing to sustainable and efficient renewable energy technologies.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4650-4667"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237297","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":"Dynamic Characteristics of Radiative Fluid Flow Across Time-Dependent Variable Radius Stretching Horizontal Cylinder With Chemical Reactive Process","authors":"Essam M. Elsaid,&nbsp;Tarek G. Emam,&nbsp;Mohamed R. Eid","doi":"10.1002/htj.70024","DOIUrl":"https://doi.org/10.1002/htj.70024","url":null,"abstract":"<div>\u0000 \u0000 <p>This study explores the flow dynamics and heat transference of fluid along a stretchable horizontal cylinder with a variable radius depending on time in the existence of chemical reactions and thermal radiation. The mathematical model comprises a set of partial differential equations with boundary conditions that describe the changing flow, thermal radiation, mass movement, suction or injection, and chemical reactions. Similarity transformation reduces such a system to a set of ordinary differential equations. The resulting system is solved using numerical methods to find how velocity, temperature, and concentration change based on the similarity variable, showing the effects of important factors like the unsteadiness parameter, the Schmidt number, suction/injection, thermal radiation, and the chemical reaction rate. This study validates its numerical technique by comparing certain findings to those published in the literature for constraints. The findings show that the increase of the unsteadiness parameter enhances the flow acceleration. Increasing the unsteadiness parameter also increases the fluid temperature and concentration. Chemical reaction parameters tend to modify the concentration distribution by enhancing the species diffusion. Additionally, higher values of thermal radiation and suction parameters decrease fluid temperature. These findings help control the thermal and mass transport processes in chemical reactors, heat exchanger systems, polymer extrusions, and many other engineering applications.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4723-4734"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237299","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 Simulation of Time Fractional Nonlinear Heat Transfer Equation With Predictor-Corrector Approach","authors":"Daasara Keshavamurthy Archana,&nbsp;Doddabhadrappla Gowda Prakasha","doi":"10.1002/htj.70017","DOIUrl":"https://doi.org/10.1002/htj.70017","url":null,"abstract":"<div>\u0000 \u0000 <p>This article enables the changing specific heat coefficient to solve two nonlinear heat transfer problems. With mechanical engineering at the cutting edge, efficient heat transmission is essential to the effectiveness, safety, and performance of many engineering systems. The transfer of heat occurs through multiple pathways, including conduction, convection, and radiation, each playing a vital role in shaping the thermal landscape of modern technologies. We propose a fractional-order approach to reduce the complexity of the study. Here, using the Caputo fractional derivative (CFD), we examine and evaluate the solutions of the considered problems using the Predictor-Corrector method (PCM). To verify the reliability of the considered approach, the present findings are compared with those of the variational iteration method (VIM), homotopy perturbation method (HPM), hermite wavelet method (HWM), differential transformation method (DTM) and the accurate solutions. The PCM is typically more advantageous for actual numerical calculations, particularly when flexibility, stability, and accessibility of implementation are needed. The outcomes suggest that the PCM can forecast the solution of such problems with more appropriate results.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4618-4625"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237293","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":"Performance of a Combined Hot-Air–Infrared Hybrid Convective Dryer for Zucchini Slices","authors":"Mawada Al-Khayari,&nbsp;Wajud Al-Ghafri,&nbsp;Ohood Al-Ghadani,&nbsp;Hemanatha Jayasuriya,&nbsp;Pankaj B. Pathare,&nbsp;Mohammed Al-Belushi","doi":"10.1002/htj.70025","DOIUrl":"https://doi.org/10.1002/htj.70025","url":null,"abstract":"<div>\u0000 \u0000 <p>Drying is one of the most popular methods used in the food industry to reduce postharvest losses, extend shelf life, add value, and reduce handling. However, conventional drying methods such as hot-air (HA) dryers are time-consuming, energy-intensive, and can affect the food quality. To address these challenges, infrared (IR) drying has been added as a booster heat source, ensuring faster drying, energy saving, and quality improvement, since each method has its limitations. Therefore, combining HA and IR drying has been shown to be a more efficient technique, ensuring better drying performance. The aim of this study is to design and test the performance of using the HA and IR hybrid dryer for drying zucchini, by evaluating the zucchini quality attributes, such as moisture content (MC), water activity, rehydration ratio (RR), and shrinkage in diameter. In this study, different samples of zucchini slices were dried in a hybrid dryer under three different combinations of heat air and air speed, selected based on preliminary trials, including IR2-S1-H2, IR2-S2-H2, and IR2-S2-H1, where IR2 refers to the use of two IR tubes, S refers to the air speed and H indicates the heater level. The physicochemical properties of dried zucchini samples were analyzed and compared, including MC, moisture ratio, drying rate, water activity, rehydration, and diameter shrinkage. The results showed that IR2-S2-H2 was the fastest among the three drying combinations, reaching 10% MC within 40 min, while IR2-S1-H2 and IR2-S2-H1 required 60 and 80 min, respectively. The Midilli–Kucuk model offered the best-fit model for the MC data of IR2-S1-H2 and IR2-S1-H1 (<i>R</i>² = 0.9999 and 0.9999, RMSE = 1.6340 × 10⁻⁶ and 0.0011, respectively), while the logarithmic model provided the best-fit model for IR2-S2-H2 (<i>R</i>² = 0.9999, RMSE = 1.5421 × 10⁻⁷). All dryer combinations resulted in an RR of 4.67–5.80, and the water activity of dried zucchini samples was within the recommended food safety threshold (water activity = 0.207–0.411 &lt; 0.6). In addition, the lowest diameter shrinkage (28.21%) was observed with the IR2-S2-H1 condition. This study recommends further research to optimize drying parameters and improve food quality as well as to evaluate the application of this dryer to other fruits and vegetables.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4735-4744"},"PeriodicalIF":2.6,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237302","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":"Experimental and Numerical Investigation of the Effects of Amplitude, Pitch, and Chevron Angle in a Brazed Plate Heat Exchanger","authors":"Madhu Kalyan Reddy Pulagam,&nbsp;Debashis Pasa,&nbsp;Sachindra Kumar Rout,&nbsp;Sunil Kumar Sarangi","doi":"10.1002/htj.70018","DOIUrl":"https://doi.org/10.1002/htj.70018","url":null,"abstract":"<div>\u0000 \u0000 <p>Brazed plate heat exchangers are renowned for their compact design and exceptional heat transfer capabilities. However, their intricate geometry sets them apart from other type of heat exchangers. Traditionally, studies have been somewhat limited in exploring diverse geometrical parameters due to the considerable manufacturing costs associated with each variation. Moreover, the complexity of the geometry poses challenges for simulation and numerical analyses, often resulting in inefficient models due to the generation of a large number of elements. To address these challenges, simulation models have been devised leveraging the concept of periodicity and simulated using periodic boundary conditions within ANSYS Fluent. This novel approach enables the variation and simulation of all geometric features with significantly fewer elements. Parameters such as pitch, amplitude, and chevron angle have been subjected to variation and simulated under similar conditions which was not done in any previous studies. The findings underscore the pronounced influence of the chevron angle, whereas the impact of amplitude and pitch becomes significant primarily at higher Reynolds numbers, affecting heat transfer and pressure drop. Furthermore, the discussion extends to an experimental setup proposed to evaluate the heat performance of heat exchanger across varying heat loads and flow rates.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4626-4639"},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237179","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":"Empirical Study of Performance Improvement by Cylindrical Solar Still Height Utilizing a Hemispherical Dome","authors":"Ammar Muslim Hadi,&nbsp;Zahraa Hamzah Hasan,&nbsp;Hussein Awad Kurdi Saad,&nbsp;Wisam A. Abd Al-wahid","doi":"10.1002/htj.70014","DOIUrl":"https://doi.org/10.1002/htj.70014","url":null,"abstract":"<div>\u0000 \u0000 <p>The shapes of solar stills have a direct effect on the behavior of these stills. In the present work, a new cylindrical solar design still covered by a hemispherical dome was fabricated. The purpose of this study is to find the effect of this modification on temperature distribution inside the still, hence, to find the effect on productivity. A steady state case of solar radiation conditions with fixed morphological conditions was used to concentrate only on the new design effect. The height of the used cylinder was increased by 10 cm in each case, starting from zero in the simple hemispherical solar still case (HSC). Changing cover design was found to play a great role in present still behavior. Temperature values decreased as cylinder height increased compared to that of HSC, while the productivity of the case of 10 cm height showed a maximum increase of 9.4% compared to that of HSC. Productivity values decreased to the maximum yield as further cylinder height was applied in the other cases. Experiments show that this new design can decrease the temperature values of all still's parts for a constant evaporation area, which makes it a suitable design for using stills with heat transfer enhancements.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4596-4602"},"PeriodicalIF":2.6,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237365","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":"Exploring the Interactions of Electroosmotic Activity of Couple-Stress Fluid With Ionic Liquid Through a Microfluidic Tapered System Undergoes Thermally Induced Energy Dissipation","authors":"S. Ravikumar,&nbsp;Oluwole Daniel Makinde","doi":"10.1002/htj.70008","DOIUrl":"https://doi.org/10.1002/htj.70008","url":null,"abstract":"<div>\u0000 \u0000 <p>The aim of this study is to comprehensively examine the behavior and properties of a couple-stress fluid during electroosmosis, heat radiation, and the effects of an inclined magnetic field in a horizontally aligned, tapered microfluidic conduit. To simplify the system, we applied the lubrication approximation and the Debye–Hückel linearization method to convert the Poisson–Boltzmann equations into a linear form. An increased Hartmann number results in a higher fluid velocity because the stronger magnetic field reduces both turbulence and effective viscosity. Additionally, the electroosmosis parameter decreases fluid velocity, which carries significant implications in medical biology. Furthermore, as the Helmholtz–Smoluchowski velocity rises, so does fluid velocity. In physiological settings, the correlation between Helmholtz–Smoluchowski velocity and fluid velocity aids in regulating normal bodily functions. Notice that the porosity parameter enhances fluid temperature. Additionally, thermal radiation declines fluid temperature. Moreover, fluid temperature increases due to Joule heating. Thermal radiation and Joule heating influence heat transfer rates, as shown by fluctuations in the Nusselt number, affecting the accuracy of thermal control in microscale biomedical devices. This study presents a novel investigation into the electroosmotic flow of couple-stress fluid in a tapered microfluidic system. Significant innovations encompass the identification of the Hartmann number's role in enhancing fluid velocity through the reduction of turbulence and viscosity, with relevant implications for cardiovascular evaluations and medical imaging. The physiological significance of the Helmholtz–Smoluchowski velocity in optimizing fluid flow regulation is considerable. This study uniquely examines the interplay of thermal radiation, Joule heating, and porosity with fluid temperature, which is critical for advancing applications, like, electrosurgery and infrared thermography. The research enhances the understanding of electroosmosis-based methods, offering new insights into their potential applications in cancer therapy. These significant discoveries provide innovative solutions in diagnostics, drug delivery, and therapeutic systems by integrating fundamental fluid mechanics with advanced biomedical applications.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 7","pages":"4498-4518"},"PeriodicalIF":2.6,"publicationDate":"2025-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145237294","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}