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

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 >

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

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 >

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

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 >

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

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 >

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

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 >

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

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 >

Heng Zhang^1,2, Chao Su^2,*, Xiaohu Chen¹, Zhizhong Song¹, Weijie Zhan³

CMES-Computer Modeling in Engineering & Sciences, Vol.140, No.3, pp. 2977-3000, 2024, DOI:10.32604/cmes.2024.047972

Abstract Temperature-induced cracking during the construction of mass concrete is a significant concern. Numerical simulations of concrete temperature have primarily assumed that the concrete is placed in an open environment. The problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation boundary. However, in the case of tubular concrete structures, where air inlet and outlet are relatively limited, the internal air temperature does not dissipate promptly to the external environment as it rises. To accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces… More >

Yasser Jebbar^1,2,*, Fadhil Fluiful², Wisam Khudhayer³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1279-1297, 2024, DOI:10.32604/fdmp.2024.050753

Abstract This study includes an experimental and numerical analysis of the performances of a parabolic trough collector (PTC) with and without cylindrical turbulators. The PTC is designed with dimensions of 2.00 m in length and 1.00 m in width. The related reflector is made of lined sheets of aluminum, and the tubes are made of stainless steel used for the absorption of heat. They have an outer diameter of 0.051 m and a wall thickness of 0.002 m. Water, used as a heat transfer fluid (HTF), flows through the absorber tube at a mass flow rate… More >

Yi Tu^1,*, Yuan Wu², Yu Zeng³

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 989-1014, 2024, DOI:10.32604/fdmp.2024.045624

Abstract The formation of ice on the leading edge of aircraft engines is a serious issue, as it can have catastrophic consequences. The Swirl Anti-Icing (SAI) system, driven by ejection, circulates hot fluid within a 360° annular chamber to heat the engine inlet lip surface and prevent icing. This study employs a validated Computational Fluid Dynamics (CFD) approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing chamber. Additionally, the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the… More >

Shuilian Li¹, Fan Zeng¹, Xinli Wei^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.5, pp. 939-955, 2024, DOI:10.32604/fdmp.2023.043614

Abstract In order to increase the efficiency of solar air collectors, a new variant with a protrusion is proposed in this study, and its performances are analyzed from two points of view, namely, in terms of optics and thermodynamics aspects. By comparing and analyzing the light paths of the protrusion and the dimple, it can be concluded that when sunlight shines on the dimple, it is reflected and absorbed multiple times, whereas for the sunlight shining on the protrusion, there is no secondary reflection or absorption of light. When the lighting area and the properties of… More >