Heat Transfer最新文献

{"title":"Mathematical Modeling of Self-Heating and Self-Ignition Behavior of Lignocellulosic Biomass Fuel in a Rectangular Stockpile: A Spectral Approach","authors":"Adeshina Taofeeq Adeosun,&nbsp;Jacob Abiodun Gbadeyan","doi":"10.1002/htj.23317","DOIUrl":"https://doi.org/10.1002/htj.23317","url":null,"abstract":"<div>\u0000 \u0000 <p>The adoption of lignocellulosic biomass fuels as substitutes for fossil fuels has been known to lower greenhouse gas emissions and enhance the quality of life. However, their tendency for self-heating, which could result in explosions, presents a significant challenge. To overcome this challenge, a mathematical model for the flow of biomass fuel in a rectangular stockpile is considered in this study. It is assumed that lignocellulosic material behaves like a Bingham fluid with a large yield stress, and the chemical reaction in the biomass fuel particles follows Arrhenius's kinetic theory. The governing equations of the problem are strongly nonlinear. Hence, a numerical method (Chebyshev spectral collocation method) is adopted to provide a solution to the governing equations. Our results indicate that the delay of self-ignition can be achieved by enhancing the thermal Biot number and activation energy while reducing the Rayleigh number and mass Biot number. This study encourages the wider use of biomass fuels by addressing safety issues, advocating for sustainable energy practices, and improving environmental conservation.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2691-2702"},"PeriodicalIF":2.8,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944544","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":"Finite Element Numerical Simulation of Free Convection Heat Transfer in a Square Cavity Containing an Inclined Prismatic Obstacle With Machine Learning Optimization","authors":"Perepi Rajarajeswari,&nbsp;Thilagavathi Arasukumar,&nbsp;O. Anwar Bég,&nbsp;Tasveer A. Bég,&nbsp;S. Kuharat,&nbsp;P. Bala Anki Reddy,&nbsp;V. Ramachandra Prasad","doi":"10.1002/htj.23315","DOIUrl":"https://doi.org/10.1002/htj.23315","url":null,"abstract":"<div>\u0000 \u0000 <p>The present work describes a numerical simulation of free convection heat transfer inside a square cavity containing a prismatic obstacle at various angles of inclination. The nondimensional governing equations are discretized by the finite element method and solved in the commercial software “COMSOL Multiphysics 6.1” with appropriate boundary conditions. The effect of prominent parameters on streamline, isotherm contours, and local Nusselt number profiles are depicted graphically. The control parameters are the Prandtl number and Rayleigh number (10³ ≤ <i>Ra</i> ≤ 10⁶). The study considers air as the circulating fluid with the Prandtl number, <i>Pr</i> = 0.71. The computations are conducted for the prismatic shape at four different orientations of <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <msup>\u0000 <mn>0</mn>\u0000 \u0000 <mo>∘</mo>\u0000 </msup>\u0000 \u0000 <mo>,</mo>\u0000 \u0000 <mn>3</mn>\u0000 \u0000 <msup>\u0000 <mn>0</mn>\u0000 \u0000 <mo>∘</mo>\u0000 </msup>\u0000 \u0000 <mo>,</mo>\u0000 \u0000 <mn>4</mn>\u0000 \u0000 <msup>\u0000 <mn>5</mn>\u0000 \u0000 <mo>∘</mo>\u0000 </msup>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math>, and <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <mn>6</mn>\u0000 \u0000 <msup>\u0000 <mn>0</mn>\u0000 \u0000 <mo>∘</mo>\u0000 </msup>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math>. The inclination angle of the prismatic obstacle is observed to exert a significant role in the distribution of heat and momentum inside the square cavity. Furthermore, neural network approaches are used for optimizing the thermal performance of the system, via Bayesian regularization machine learning analysis and Levenberg–Marquardt algorithms. The study finds applications in solar collectors, fuel cells, and so forth.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2675-2690"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945006","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":"Next-Generation Fin-Structured PCM Solutions for Effective Thermal Management of Li-Ion Batteries","authors":"S. M. D. Shehabaz,&nbsp;S. K. Gugulothu,&nbsp;Raju Muthyala,&nbsp;Praveen Barmavatu","doi":"10.1002/htj.23307","DOIUrl":"https://doi.org/10.1002/htj.23307","url":null,"abstract":"<div>\u0000 \u0000 <p>The efficiency and effectiveness of a battery thermal management system (BTMS) primarily depend on the limited heat dissipation capacity of the phase change material (PCM). In this study, a novel extended-surface PCM composite is designed to enhance the thermal management of lithium-ion batteries. Numerical investigations using ANSYS Fluent reveal that incorporating metallic fins significantly improves heat transfer by creating a multichannel thermal network. The modified BTMS demonstrates a 92.5% increase in operational duration compared with conventional PCM systems. Additionally, increasing the fin length from 6 to 14 mm improves operational time by 13.62%, while uniform fin placement enhances thermal performance by 9.25%. At higher ambient temperatures (20°C–50°C), the system achieved a 1.96-fold increase in operational duration compared with traditional setups. Furthermore, the optimized BTMS maintained the battery temperature below 60°C for 41%–93% longer durations across varying configurations, outperforming existing systems in high-temperature environments. These findings validate the effectiveness of extended-surface PCM composites in overcoming the limitations of conventional BTMSs, enhancing both battery performance and longevity.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2659-2674"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945054","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 Comprehensive Analysis of Stratification and Chemical Reaction on MHD Flow Along an Impulsively Started Infinite Vertical Plate in Presence of Radiation and Heat Source Through Porous Medium","authors":"Digbash Sahu,&nbsp;Rudra Kanta Deka,&nbsp;Pappu Das,&nbsp;Rakesh Rabha","doi":"10.1002/htj.23313","DOIUrl":"https://doi.org/10.1002/htj.23313","url":null,"abstract":"<div>\u0000 \u0000 <p>This study analytically investigates the impact of thermal stratification on unsteady magnetohydrodynamic flow along an infinite vertical plate in a porous medium, incorporating chemical reaction, radiation, and heat source. Using the Laplace transform method, exact solutions for velocity, temperature, and concentration profiles were derived, offering a novel approach without approximations. Results show that increased stratification significantly reduces velocity and temperature profiles, with peak velocity decreasing by approximately 35% compared with the nonstratified case (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <mrow>\u0000 <mi>γ</mi>\u0000 \u0000 <mo>=</mo>\u0000 \u0000 <mn>0</mn>\u0000 </mrow>\u0000 </mrow>\u0000 </mrow>\u0000 </semantics></math>). Higher radiation and Darcy number enhance heat transfer, as reflected in an increased Nusselt number. These findings offer critical insights for optimizing thermal and mass transfer systems in industrial applications, such as cooling processes, energy optimization, and pollution control.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2645-2658"},"PeriodicalIF":2.8,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945023","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":"Optimization of Argon Gas Flow Rate for High-Quality Germanium Crystal Growth in Czochralski Method","authors":"Sanaz Hadidchi,&nbsp;Mohammad Hossein Tavakoli","doi":"10.1002/htj.23301","DOIUrl":"https://doi.org/10.1002/htj.23301","url":null,"abstract":"<div>\u0000 \u0000 <p>The quality of germanium crystals grown using the Czochralski method critically depends on growth conditions, particularly the flow rate of inert gases. Despite its importance, the impact of argon gas flow rate on the thermal field, melt convection, and resultant crystal quality has not been comprehensively studied. To bridge this gap, we employed computational fluid dynamics and finite element method analysis to investigate argon flow rates ranging from 1 to 30 L/min. Our results reveal that increasing the argon flow rate improves not only crystal cooling but also heightens thermal stress by approximately 15% and dislocation density by 25%, with significant freezing at the melt–crucible interface for higher rates. These findings suggest that gas flow rate optimization is key to minimizing defects and enhancing crystal quality. This study provides novel insights into the thermal and flow dynamics within a Czochralski germanium growth setup, offering practical guidance for semiconductor manufacturing.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2632-2644"},"PeriodicalIF":2.8,"publicationDate":"2025-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945017","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":"Enhancement of Heat Transfer in Double-Pipe Heat Exchangers Using Wavy Edge Twisted Tape With Varying Twist Ratios and Perforated Diameters","authors":"Zainab Mahdi Saleh,&nbsp;Riyadh S. Al-Turaihi,&nbsp;Zena Khalefa Kadhim","doi":"10.1002/htj.23311","DOIUrl":"https://doi.org/10.1002/htj.23311","url":null,"abstract":"<div>\u0000 \u0000 <p>A computational simulation of an enhanced double-pipe heat exchanger equipped with inserted twisted tape. The Navier–Stokes, energy, and turbulence equations were employed to represent fluid flow and heat transmission, utilizing a <i>k</i>–<i>ε</i> model for turbulence. ANSYS Fluent 22 is used to solve the governing equations and investigate how the perforated wavy edge tape, along with the diameter of its holes (5, 15, and 30 mm), twisting ratio of a wavy edge twisted tape ratio (0.5, 1, 1.5, 2, 2.5, and 3), affects heat transfer and pressure drop at ranging Reynolds numbers (6957–187,837), compared to a plain tube. Hot air is utilized in the inner tube, which incorporates twisted tapes to enhance turbulence and heat transfer and cold oil in the outer tube to establish a counter-flow system and experience the improved flow's effects. Results demonstrate significant improvements in oil outlet temperature. The Nusselt number (<i>Nu</i>) increases with increasing Reynolds numbers and twist ratios; the enhanced tubes increase <i>Nu</i> and friction factor by about 41% and 2.6 times greater than the smooth tube. Increasing the Reynolds number and twisted tape ratio generally leads to higher heat transfer rates and pressure drop. Optimal configurations of PWETT with Tr = 2 and WET with a hole diameter of 30 mm gave the best thermal performance index (1.11 and 1.24) when balancing heat transfer and pressure drop. The findings provide valuable insights for designing and optimizing heat exchangers in applications demanding efficient heat transfer.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2609-2631"},"PeriodicalIF":2.8,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945034","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":"Assessment Improvement of Heat Performance and Hydraulic Thermal Flow in a Three-Dimensional Tube Equipped With Different Turbulator Corrugated Arrangements","authors":"Saad Raad Al-Haidari,&nbsp;Ahmed Ramadhan Al-Obaidi","doi":"10.1002/htj.23296","DOIUrl":"https://doi.org/10.1002/htj.23296","url":null,"abstract":"<div>\u0000 \u0000 <p>Corrugated pipe is used in many engineering applications because of its high performance compared with smooth pipe. This research involved numerical simulations and experimental testing of a circular tube with a modified flow path to improve the heat transfer performance of heat exchangers. The focus was on enhancing mixing and creating vortex flows within the tube to increase heat exchange efficiency. The impact of seven design factors, including ring diameters (RD) and the pitch between ring pitches (RP), on thermal–hydraulic performance was investigated. Water is used as the working fluid and the flow regime ranges from 4000 to 15,000, indicating turbulent flow. A constant heat flux of 25,500 W/m² is applied, and the water enters the system at a temperature of 298 K (25°C). The properties of water are assumed to remain constant throughout the flow with flow conditions, such as a steady state (the flow conditions do not change with time), incompressible flow (the density of the fluid remains constant), and no-slip condition (the fluid velocity at the surface of any solid boundary is zero). Corrugated tubes consistently outperformed smooth tubes in heat transfer due to increased flow mixing and separation. Both increasing the Reynolds number and decreasing the design factors led to the formation of mixing and vortex patterns. In RD configurations, the Nusselt number saw an average improvement of approximately 45.6%, while the friction factor increased between 19% and 57%. RP configurations demonstrated a broader range of Nusselt number enhancements, reaching up to 35%, and friction factor increases ranging from 15% to 42%. Rings can significantly enhance the thermal–hydraulic performance of tubes. However, the best configuration depends on the specific application. The configuration with the highest performance, resulting in a 1.38 increase in performance evaluation factor, was obtained using an RD of 1 mm and an RP of 20 mm. The simulated and experimental data showed excellent agreement, with a maximum discrepancy of less than 11% for both smooth and dimpled tubes.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2594-2608"},"PeriodicalIF":2.8,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143945033","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":"Design and Testing of a Single-Slope Solar Still With a Semi-Elliptical Absorbent Base: An Experimental and Numerical Study","authors":"Muntadher Mohammed Ali Saeed,&nbsp;Hassanain Ghani Hameed,&nbsp;Assaad A. Abbass","doi":"10.1002/htj.23258","DOIUrl":"https://doi.org/10.1002/htj.23258","url":null,"abstract":"<div>\u0000 \u0000 <p>In this article, a single-slope solar still with a semi-elliptical absorption base (SES) is designed, manufactured, and tested. The semi-elliptical solar still (SES) design reduces the sun's shadow generated by the sharp walls on the absorbent base and makes the most of the available solar radiation. We compared the performance of the proposed solar still (SES) with the conventional square base absorption solar still (CSS). The two models were made of precisely the same materials and had the same area of the absorption part. The experimental results of semi-elliptical stills showed that yield productivity increased by about 306.5% compared to conventional stills. This decreased the cost of producing a liter of fresh water from 0.0316 $ to 0.0092 $, up to 71%.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2580-2593"},"PeriodicalIF":2.8,"publicationDate":"2025-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944861","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 Impact of Relaxation Time in Piezoelectric Hollow Cylinder by Finite Element Technique","authors":"Zuhur Alqahtani,&nbsp;Ibrahim Abbas,&nbsp;Alaa A. El-Bary,&nbsp;Areej Almuneef","doi":"10.1002/htj.23310","DOIUrl":"https://doi.org/10.1002/htj.23310","url":null,"abstract":"<div>\u0000 \u0000 <p>This study examines the thermo-electro-elastic responses of a long hollow cylindrical piezoelectric material due to a pulse heating flux on its surface. Formulations suggested by Lord and Shulman for generalized piezothermoelastic systems are used. The response of the vessel is modeled under axisymmetric conditions, leading to the formulation of three coupled governing equations: the motion, Maxwell and the energy formulations. The finite element approach is used to solve these equations numerically. The Newmark time-marching methodology is used to derive the temporal evolution. The presentation of novel numerical results provides insights into the dynamic behaviors of the piezoelectric cylinder under transient heat settings. The responses of pulse heating flux and relaxation time on the coupling between mechanical, thermal and electrical fields are highlighted in this work, providing useful.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2572-2579"},"PeriodicalIF":2.8,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944957","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":"Thermal Characteristics of Organic and Inorganic Eutectic Phase Change Materials Using T-History and DSC Method During Solidification Phase","authors":"Utkarsh Srivastava,&nbsp;Rashmi Rekha Sahoo","doi":"10.1002/htj.23295","DOIUrl":"https://doi.org/10.1002/htj.23295","url":null,"abstract":"<div>\u0000 \u0000 <p>The temperature-history (temp-hist) method offers a straightforward and effective technique for ascertaining the thermal-physical properties of phase change materials (PCMs). This study explores three combinations of eutectic phase change materials (EPCMs): organic–organic, organic–inorganic, and inorganic–inorganic, aiming to identify the most suitable EPCM based on their heat conduction coefficient, heat capacity, and enthalpy of fusion for the solidification process. The experimental findings revealed that inorganic–inorganic EPCM demonstrated significantly superior thermal conductivity. Specifically, they exhibited approximately four times a 25% higher heat conduction coefficient in both solid and liquid phases compared to combinations involving organic–organic and organic–inorganic EPCM blends. Specific heat capacities and enthalpies of fusion were also analyzed, with organic–organic EPCM demonstrating superior values. The enthalpy of fusion for organic–organic EPCM surpassed that of inorganic–inorganic EPCM by 27.94% and outperformed organic–inorganic EPCM by 10.96%. Nusselt numbers and heat transfer coefficients were determined, highlighting the superior convective heat transfer efficiency of inorganic–inorganic EPCM. The lowest endothermic peak is 45°C for inorganic–inorganic EPCM from DSC analysis. The EPCMs' latent heat, specific heat, and phase transition temperatures nearly match the standard DSC method, proving the reliability of the lab-made T-history configuration. The results highlight how EPCM composition is crucial for achieving top-notch thermal performance, emphasizing how blending organic and inorganic materials enhances heat transfer and phase change stability.</p>\u0000 </div>","PeriodicalId":44939,"journal":{"name":"Heat Transfer","volume":"54 4","pages":"2543-2558"},"PeriodicalIF":2.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143944755","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}