Jiangfeng Guo^1,2,3,*, Hongjie Yu¹

Frontiers in Heat and Mass Transfer, Vol.22, No.6, pp. 1575-1595, 2024, DOI:10.32604/fhmt.2024.058179 - 19 December 2024

Abstract Based on the first and second laws of thermodynamics, the heat transfer and flow (thermohydraulic) characteristics of horizontal supercritical pressure CO₂ (S-CO₂) in a circular pipe under heating conditions were investigated numerically. Heating flows in two different diameters (d) of 4 and 6 mm were simulated in pipes with pressures of 8 MPa, mass fluxes (G) of 300 and 400 kg/(m²·s), and heat fluxes (q) of 50, 75 and 100 kW/m². In the d = 4 mm pipe, the peak heat transfer coefficient (h_b) was about 3 times higher than in the d = 6 mm pipe, while the entropy… More > Graphic Abstract

Ahmed Dhafer Abdulsahib^1,*, Dhirgham Alkhafaji¹, Ibrahim M. Albayati²

Frontiers in Heat and Mass Transfer, Vol.22, No.6, pp. 1777-1804, 2024, DOI:10.32604/fhmt.2024.057209 - 19 December 2024

Abstract The current study generally aims to improve heat transfer in heat sinks by presenting a numerical analysis of natural convection of an enclosure with hot right and cool left walls, and thermally insulated top and bottom walls. The cold wall included configurations (half circle/half square) in various sizes (S = 0.1, 0.2, and 0.3), numbers (N = 1, 2, 3, and 4), and locations (C = 0.35, and 0.65). A heat sink is constructed of Aluminum attached to the hot wall, and composed of five fins with protrusions. Fins of the heat sink will be… More > Graphic Abstract

Alexander Fedoseev^*, Mikhail Salnikov

Frontiers in Heat and Mass Transfer, Vol.22, No.6, pp. 1679-1694, 2024, DOI:10.32604/fhmt.2024.056999 - 19 December 2024

Abstract In order to research the process of boiling occurring on a porous surface, a model of multiple blocks was developed. The mathematical basis of these blocks is the lattice Boltzmann method in combination with heat transfer equation. The reported complex allows one to obtain the boiling curves for various wall superheats and to find the optimal parameters of a porous heater in terms of heat transfer enhancement. The porous heater structure is specified as a skeleton of square metal heaters located in the lower part of the computational domain. The calculations were performed for the… More > Graphic Abstract

Ivan Malakhov^1,*, Anton Surtaev^1,2, Vladimir Serdyukov^1,2, Ali Kosar³, Alexander Pavlenko¹

Frontiers in Heat and Mass Transfer, Vol.22, No.6, pp. 1645-1660, 2024, DOI:10.32604/fhmt.2024.056664 - 19 December 2024

Abstract To date, using biphilic surfaces is one of the most promising methods for enhancing heat transfer and critical heat flux during boiling simultaneously. However, most of studies on the effect of biphilic surfaces on boiling performance have been carried out under atmospheric pressure conditions. In this context, the issues of heat transfer enhancement and stabilization of the boiling process at subatmospheric pressures are particularly critical due to the interesting characteristics of boiling heat transfer and bubble dynamics at subatmospheric pressures and their practical significance including aerospace applications. This paper investigates the effect of the pitch… More > Graphic Abstract

Wei Lu^1,3, Yujie Chen^2,*, Bo Yu², Dongliang Sun², Wei Zhang², Yanru Yang^1,3, Xiaodong Wang^1,3,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.012265

Abstract Flow boiling offers superior heat transfer performance compared to single-phase flow, therefore holding significant potential for application in thermal management. In mini-channel applications, due to their narrow dimensions, the size characteristics of the channel have a particularly notable impact on bubble dynamics and flow boiling heat transfer performance. This study employs the VOSET method to explore the impact of different aspect ratios (1:3, 1:2, 1:1, 2:1, 3:1) on the heat transfer performance of mini-channels. By maintaining a consistent equivalent diameter across the channels, the study aims to unveil the mechanism by which aspect ratios affect… More >

Sara Salem Alzaid¹, Badr Saad T. Alkahtani^1,*, Kumar Chandan², Ravikumar Shashikala Varun Kumar³

CMES-Computer Modeling in Engineering & Sciences, Vol.141, No.3, pp. 2555-2574, 2024, DOI:10.32604/cmes.2024.055312 - 31 October 2024

Abstract Heat transport has been significantly enhanced by the widespread usage of extended surfaces in various engineering domains. Gas turbine blade cooling, refrigeration, and electronic equipment cooling are a few prevalent applications. Thus, the thermal analysis of extended surfaces has been the subject of a significant assessment by researchers. Motivated by this, the present study describes the unsteady thermal dispersal phenomena in a wavy fin with the presence of convection heat transmission. This analysis also emphasizes a novel mathematical model in accordance with transient thermal change in a wavy profiled fin resulting from convection using the… More >

Kunrong Shen^*, Wanchun Jin, Jin Wang

Frontiers in Heat and Mass Transfer, Vol.22, No.5, pp. 1361-1379, 2024, DOI:10.32604/fhmt.2024.057372 - 30 October 2024

Abstract The modified Siemens method is the dominant process for the production of polysilicon, yet it is characterised by high energy consumption. Two models of laboratory-grade Siemens reduction furnace and 12 pairs of rods industrial-grade Siemens chemical vapor deposition (CVD) reduction furnace were established, and the effects of factors such as the diameter of silicon rods, the surface temperature of silicon rods, the air inlet velocity and temperature on the heat transfer process inside the reduction furnace were investigated by numerical simulation. The results show that the convective and radiant heat losses in the furnace increased… More >

Leonid Plotnikov^*, Danil Davydov, Dmitry Krasilnikov, Vladislav Shurupov

Frontiers in Heat and Mass Transfer, Vol.22, No.5, pp. 1309-1322, 2024, DOI:10.32604/fhmt.2024.056680 - 30 October 2024

Abstract Heat engines based on reciprocating machines remain in demand as energy converters in a variety of industries around the world. The aim of the study was to evaluate the gas-dynamic, consumable and heat exchange characteristics of non-stationary air flows in a supply system with transverse profiling of valve channels based on experimental studies. Valve channels with cross sections in the form of a circle, square and triangle were used to control the consumable and heat exchange characteristics of the flows in the supply system of the reciprocating-engine model. The article presents data on changes in… More >

Zhengyuan Pei¹, Yasushi Koito^2,*

Frontiers in Heat and Mass Transfer, Vol.22, No.5, pp. 1381-1397, 2024, DOI:10.32604/fhmt.2024.056624 - 30 October 2024

Abstract Extended experiments were conducted on the oscillation characteristics of merged liquid slugs in a horizontally oriented polymer pulsating heat pipe (PHP). The PHP’s serpentine channel comprised 14 parallel channels with a width of 1.3 and a height of 1.1 . The evaporator and condenser sections were 25 and 50 long, respectively, and the adiabatic section in between was 75 mm long. Using a plastic 3D printer and semi-transparent filament made from acrylonitrile butadiene styrene, the serpentine channel was printed directly onto a thin polycarbonate sheet to form the PHP. The PHP was charged with hydrofluoroether-7100.… More >

Mumtaz Khan^1,*, Muhammad Shoaib Anwar², Mudassar Imran³, Amer Rasheed⁴

Frontiers in Heat and Mass Transfer, Vol.22, No.5, pp. 1399-1419, 2024, DOI:10.32604/fhmt.2024.056597 - 30 October 2024

Abstract This study employs the Buongiorno model to explore nanoparticle migration in a mixed convection second-grade fluid over a slendering (variable thickness) stretching sheet. The convective boundary conditions are applied to the surface. In addition, the analysis has been carried out in the presence of Joule heating, slips effects, thermal radiation, heat generation and magnetohydrodynamic. This study aimed to understand the complex dynamics of these nanofluids under various external influences. The governing model has been developed using the flow assumptions such as boundary layer approximations in terms of partial differential equations. Governing partial differential equations are… More >