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Kenta Hashimoto¹, Guohui Sun¹, Yasushi Koito^2,*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 687-702, 2024, DOI:10.32604/fhmt.2024.052928 - 11 July 2024
Abstract Centered or striped wick structures have been used to develop ultrathin heat pipes. Differing from traditional heat pipes, the centered or striped wick structures leave noncontact container surfaces with the wick structure. In this study, experiments and numerical analyses were conducted to investigate the influence of these noncontact surfaces. In the experiments, a strip-shaped wick structure was placed vertically, the top was sandwiched between wider rods and the bottom was immersed in a working fluid. The rod width was greater than the wick width; thus, noncontact surfaces were left between the rod and the wick… More >

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Randeep Singh^1,*, Tomoki Oridate², Tien Nguyen²
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 703-717, 2024, DOI:10.32604/fhmt.2024.050744 - 11 July 2024
Abstract Electrification of vehicles intensifies their cooling demands due to the requirements of maintaining electronics/electrical systems below their maximum temperature threshold. In this paper, passive cooling approaches based on heat pipes have been considered for the thermal management of electric vehicle (EV) traction systems including battery, inverter, and motor. For the battery, a heat pipe base plate is used to provide high heat removal (180 W per module) and better thermal uniformity (<5°C) for the battery modules in a pack while downsizing the liquid cold plate system. In the case of Inverter, two phase cooling system… More >

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Xiaojun Li, Fuyong Su^*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 719-732, 2024, DOI:10.32604/fhmt.2024.051950 - 11 July 2024
（This article belongs to the Special Issue: Heat and Mass Transfer in Fire)
Abstract In order to study the effect of oxygen-enriched combustion technology on the temperature field and NO emission in the continuous heating furnace, this paper studies the oxygen-enriched combustion of a pushing steel continuous heating furnace in a domestic company. This study utilizes numerical simulation method, establishes the mathematical models of flow, combustion and NO generation combustion process in the furnace and analyzes the heat transfer process and NO generation in the furnace under different air oxygen content and different wind ratio. The research results show that with the increase of oxygen content in the air, More >

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316

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Abdellatif El Hannaoui^1,*, Rachid Boutarfa¹, Chadia Haidar²
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 733-746, 2024, DOI:10.32604/fhmt.2024.050520 - 11 July 2024
（This article belongs to the Special Issue: Passive Heat Transfer Enhancement for Single Phase and Multi-Phase Flows)
Abstract The proposed work focuses on the in-depth study of convective heat transfer in the unconfined air gap of a discoidal rotor-stator system. The rotary cooling mechanism is achieved by the injection of two air jets, while the cavity geometry is characterized by a dimensionless parameter G. The numerical analysis primarily concentrated on the effect of flow velocity and rotation on the heat exchange process. More precisely, the range of analysis extends from the rotational Reynolds number to , while varying the Reynolds value of the jet in a range from to . To carry out More >

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320

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S. M. Hosseinalipour^*, S. Asiaei^*, Ammar A. Hussain Al-Taee
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 747-767, 2024, DOI:10.32604/fhmt.2024.051541 - 11 July 2024
（This article belongs to the Special Issue: Multiscale Heat and Mass Transfer and Energy Conversion)
Abstract This paper is part of a series addressing the urgent need for effective technologies to reduce energy demand and mitigate climate impact. This study focused on the implementation and development of dynamic insulation technology for a sustainable and energy-efficient future in the region, especially in Iraq. The study assessed the energy efficiency of dynamic insulation technology by analyzing three wall models (static, dynamic, and modified) during the winter season. This paper expands the analysis to include a hot, dry summer scenario, providing valuable insights into the year-round performance of dynamic walls and enabling sustainable and More >

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272

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Abir Abboud¹, Zakaria Triki¹, Rachid Djeffal², Sidi Mohammed El Amine Bekkouche², Hichem Tahraoui^1,3,4, Abdeltif Amrane⁴, Aymen Amin Assadi⁵, Lotfi Khozami⁵, Jie Zhang^6,*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 769-789, 2024, DOI:10.32604/fhmt.2024.050330 - 11 July 2024
（This article belongs to the Special Issue: Heat and Mass Transfer in Thermal Energy Storage)
Abstract As buildings evolve to meet the challenges of energy efficiency and indoor comfort, phase change materials (PCM) emerge as a promising solution due to their ability to store and release latent heat. This paper explores the transformative impact of incorporating PCM on the hygrothermal dynamics of multi-zone constructions. The study focuses on analyzing heat transfer, particularly through thermal conduction, in a wall containing PCM. A novel approach was proposed, wherein the studied system (sensitive balance) interacts directly with a latent balance to realistically define the behavior of specific humidity and mass flow rates. In addition, More >

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277

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Zhisheng Xu^*, Sohail Mahmood, Zihan Yu
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 791-816, 2024, DOI:10.32604/fhmt.2024.051058 - 11 July 2024
（This article belongs to the Special Issue: Heat and Mass Transfer in Fire)
Abstract The centralized smoke exhaust system of shield tunnel is an important determinant for tunnel fire safety, and the use of different design parameters of the tunnel smoke exhaust system will affect the smoke exhaust effect in the tunnel, and the influence of different design parameters on the smoke exhaust effect and temperature attenuation of the tunnel can help engineers in designing a more effective centralized smoke exhaust system for the tunnel. In this paper, the Fire Dynamic Simulator (FDS) is utilized to examine smoke exhaust vent settings for a centralized exhaust system in shield tunnel… More >

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Md. Fayz-Al-Asad^1,4, F. Mebarek-Oudina^2,*, H. Vaidya³, Md. Shamim Hasan⁴, Md. Manirul Alam Sarker⁴, A. I. Ismail⁵
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 817-837, 2024, DOI:10.32604/fhmt.2024.050814 - 11 July 2024
（This article belongs to the Special Issue: Advances in Computational Thermo-Fluids and Nanofluids)
Abstract The goal of this paper is to represent a numerical study of magnetohydrodynamic mixed convection heat transfer in a lid-driven vertical wavy enclosure with a fin attached to the bottom wall. We use a finite element method based on Galerkin weighted residual (GWR) techniques to set up the appropriate governing equations for the present flow model. We have conducted a parametric investigation to examine the impact of Hartmann and Richardson numbers on the flow pattern and heat transmission features inside a wavy cavity. We graphically represent the numerical results, such as isotherms, streamlines, velocity profiles,… More >

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Karam H. Mohammed¹, Ashraf E. Al-Mirani¹, Bashar Mahmood Ali², Omar Rafae Alomar^1,*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 839-854, 2024, DOI:10.32604/fhmt.2024.052671 - 11 July 2024
Abstract This work involves an experimental study on the performance of automobile air-conditioning systems by adding Al₂O₃ nanoparticles to oil compressors to investigate their impacts on the enhancement of the speed cooling of refrigeration systems and to compare it with the system operated using only oil. The Al₂O₃ nanoparticles have been added to the oil compressor for different ranges of mass concentration (Ø = 0.1%, Ø = 0.15% and Ø = 0.2%). The stability of Al₂O₃ nanoparticles has been tested by direct observation for different time periods. The results indicated that the air conditioning system that operated by More >

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259

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Bo Hui^1,2,*, Shengneng Zhu², Sijun Su², Wenjuan Li²
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 855-868, 2024, DOI:10.32604/fhmt.2024.051387 - 11 July 2024
（This article belongs to the Special Issue: Two-phase flow heat and mass transfer in advanced energy systems)
Abstract The structure of the concave-convex plates has proven to be crucial in optimizing the internal flow characteristics of the electrolyzer for hydrogen production. This paper investigates the impact of the gradual expansion angle of the inlet channel on the internal flow field of alkaline electrolyzers. The flow distribution characteristics of concave-convex plates with different inlet angle structures in the electrolytic cell is discussed. Besides, the system with internal heat source is studied. The results indicate that a moderate gradual expansion angle is beneficial for enhancing fluid uniformity. However, an excessively large gradual expansion angle may More >

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Yasushi Koito^1,*, Akira Fukushima²
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 869-887, 2024, DOI:10.32604/fhmt.2024.050910 - 11 July 2024
Abstract Thermal and fluid-flow characteristics were numerically analyzed for ultra-thin heat pipes. Many studies have been conducted for ultra-thin heat pipes with a centered wick structure, but this study focused on separated wick structures to increase the evaporation/condensation surface areas within the heat pipe and to reduce the concentration of heat flux within the wick structure. A mathematical heat-pipe model was made in the three-dimensional coordinate system, and the model consisted of three regions: a vapor channel, liquid-wick, and container wall regions. The conservation equations for mass, momentum, and energy were solved numerically with boundary conditions… More >

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274

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K. S. Rajendra Prasad¹, Sathya Sai², T. R. Seetharam³, Adithya Garimella^1,*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 889-917, 2024, DOI:10.32604/fhmt.2024.047703 - 11 July 2024
（This article belongs to the Special Issue: Computational and Numerical Advances in Heat Transfer: Models and Methods I)
Abstract Numerical predictions are made for Laminar Forced convection heat transfer with and without buoyancy effects for Supercritical Nitrogen flowing over an isothermal horizontal flat plate with a heated surface facing downwards. Computations are performed by varying the value of from 5 to 30 K and ratio from 1.1 to 1.5. Variation of all the thermophysical properties of supercritical Nitrogen is considered. The wall temperatures are chosen in such a way that two values of T are less than is the temperature at which the fluid has a maximum value of C for the given pressure), More >

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291

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Xuehui Jing¹, Junchen Guo¹, Zhiyun Wang^2,*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 919-937, 2024, DOI:10.32604/fhmt.2024.049689 - 11 July 2024
（This article belongs to the Special Issue: Heat and Mass Transfer in Fire)
Abstract In this paper, the combustion conditions in the boiler furnace of a 660 MW tangential fired pulverized coal boiler are numerically simulated at 15% and 20% rated loads, to study the flexibility of coal-fired power units on ultra-low load operation. The numerical results show that the boiler can operate safely at 15% and 20% ultra-low loads, and the combustion condition in the furnace is better at 20% load, and the tangent circles formed by each characteristic section in the furnace are better, and when the boiler load is decreased to 15%, the tangent circles in… More >

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286

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M. Sridevi¹, B. Shankar Goud², Ali Hassan^3,4,*, D. Mahendar⁵
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 939-953, 2024, DOI:10.32604/fhmt.2024.050929 - 11 July 2024
（This article belongs to the Special Issue: Computational and Numerical Advances in Heat Transfer: Models and Methods II)
Abstract This study intends to evaluate the influence of temperature stratification on an unsteady fluid flow past an accelerated vertical plate in the existence of viscous dissipation. It is assumed that the medium under study is a grey, non-scattered fluid that both fascinates and transmits radiation. The leading equations are discretized using the finite difference method (FDM). Using MATLAB software, the impacts of flow factors on flow fields are revealed with particular examples in graphs and a table. In this regard, FDM results show that the velocity and temperature gradients increase with an increase of Eckert More >

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302

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Ali Abdullah Abbas Baiee, Sasan Asiaei^*, Sayed Mostafa Hosseinalipour^*
Frontiers in Heat and Mass Transfer, Vol.22, No.3, pp. 955-976, 2024, DOI:10.32604/fhmt.2024.051532 - 11 July 2024
（This article belongs to the Special Issue: Multiscale Heat and Mass Transfer and Energy Conversion)
Abstract Globally, potable water scarcity is pervasive problem. The solar distillation device is a straightforward apparatus that has been purposefully engineered to convert non-potable water into potable water. The experimental study is distinctive due to the implementation of a rotational mechanism within the pyramidal solar still (PSS), which serves to enhance the evaporation and condensation processes. The objective of this research study is to examine the impact of integrating rotational motion into pyramidal solar stills on various processes: water distillation, evaporation, condensation, heat transfer, and energy waste reduction, shadow effects, and low water temperature in saline… More >

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