Amnart Boonloi¹, Withada Jedsadaratanachai^2,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 81-106, 2023, DOI:10.32604/fhmt.2023.041547

Abstract Simulation of fluid-flow topology and thermal behavior in a round tube heat exchanger (RTHX) installed by three V-rib sets is reported. The expected phenomena for the rib installation are the generated vortex flow, impinging flow, greater fluid blending and thermal boundary layer disturbance (TBLD). These phenomena are key causes of the augmentation of heat transfer potentiality and thermal efficiency of the RTHX. Effects of rib height (b₁ = 0.05D – 0.25D and b₂ = 0.05D – 0.25D), rib pitch or rib spacing (P = D, 1.5D and 2D) and fluid directions (positive x (+x flow direction) and negative x (–x… More > Graphic Abstract

Yasushi Koito^1,*, Shoma Hitotsuya², Takamitsu Takayama², Kenta Hashimoto²

Frontiers in Heat and Mass Transfer, Vol.21, pp. 33-46, 2023, DOI:10.32604/fhmt.2023.041829

Abstract An ultra-thin flattened heat pipe has been developed with a centered wick structure. This structure is essential to make the heat pipe thinner. However, the centered wick structure reduces the evaporation and condensation surface areas of the wick structure because it is sandwiched between heat pipe walls. In this study, because detailed discussion has not been made, heat transfer experiments were conducted for the wick structure sandwiched between two solid walls. This study focused on the evaporation heat transfer characteristics from the sandwiched wick structure. The experiments were conducted with three wick structures, that is, strip-shaped sintered copper powders with… More >

Zhuohuan Hu¹, Sixian Sun¹, Chengwei Yuan¹, Yan Cao², Jiayin Xu^1,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 107-123, 2023, DOI:10.32604/fhmt.2023.041837

Abstract Loop Heat Pipe (LHP) is an efficient two-phase heat transfer device, which can be used in waste heat recovery, electronics cooling, aerospace and other fields. The wick, the core component of LHP, plays an important role in its start-up and operation. In this paper, the wick fabricated by 3D printing technology had uniform and interconnected pores. In the experiment, the position of the parallel vapor removal grooves was always fixed towards the vapor outlet. When the cylindrical wick was placed in the evaporator, the rotation angle relative to its central axis could be changed, thus changing the number and shape… More > Graphic Abstract

Huda Adel Hassan Ali, Ameer Abed Jaddoa^*, Jafaar Mohamme Daif

Frontiers in Heat and Mass Transfer, Vol.21, pp. 443-465, 2023, DOI:10.32604/fhmt.2023.042288

Abstract This paper is twofold. First, the effect of non-linear thermophysical property variation was presented using supercritical carbon dioxide (SCO₂) around the thermodynamic pivotal point. The second part exhibits an experimental examination of the heat transfer (HT) behaviour of SCO₂ in a helical tube with a hydraulic diameter of 2 mm at different mass fluxes (MF), heat fluxes (HF), and pressures (P). The experiments were carried out based on various pressures, mass fluxes, and heat fluxes for both scenarios. CO₂ was cooled in a 2 mm diameter serpentine tube made of copper material. The experimental results showed that HT degradation could… More > Graphic Abstract

Shaik Jaffrullah¹, Sridhar Wuriti^1,*, Raghavendra Ganesh Ganugapati², Srinivasa Rao Talagadadevi¹

Frontiers in Heat and Mass Transfer, Vol.21, pp. 407-426, 2023, DOI:10.32604/fhmt.2023.043305

Abstract In this particular study, we have considered the flow of Casson fluid over inclined flat and cylindrical surfaces, and have conducted a numerical analysis taking into account various physical factors such as mixed convection, stagnation point flow, MHD, thermal radiation, viscous dissipation, heat generation, Joule heating effect, variable thermal conductivity and chemical reaction. Flow over flat plate phenomena is observed aerospace industry, and airflow over solar panels, etc. Cylindrical surfaces are commonly used in several applications interacting with fluids, such as bridges, cables, and buildings, so the study of fluid flow over cylindrical surfaces is more important. Due to the… More >

Guangyan Fan, Fuyong Su^*, Cunwang Li, Bin Li

Frontiers in Heat and Mass Transfer, Vol.21, pp. 281-292, 2023, DOI:10.32604/fhmt.2023.043221

Abstract To investigate the flow and heat transfer process of blast furnace slag through the slag trench after the slag is discharged, a three-dimensional physical model is established and simulated according to the actual size of the slag trench and the physical properties of the high-temperature slag. The temperature fied and flow field distribution of the high-temperature slag liquid inside the slag trench is obtained by numerical simulation under different working conditions, and the effects of operating conditions such as slag trench inclination, high-temperature slag inlet flow rate, and inlet temperature are investigated. The results show that the flow rate of… More >

Amnart Boonloi¹, Withada Jedsadaratanachai^2,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 317-336, 2023, DOI:10.32604/fhmt.2023.044929

Abstract Thermal performance enhancement in a square channel heat exchanger (HX) using a passive technique is presented. Vortex turbulator insertion in a square channel HX as a passive technique is selected for thermal improvement. The vortex turbulator of interest is discrete X-V baffles (XVB). The discrete XVBs are inserted in the square channel with the main aim of generating vortex flow. The vortex flow generated can support the enhanced convective heat transfer coefficient and also enhance HX performance. Effects of baffle configuration (type A and B), baffle size (w/H = 0.05, 0.10, 0.15 and 0.20), baffle distance (e/H = 1, 1.5… More > Graphic Abstract

Husam Rashid Hudear^*, Saad Najeeb Shehab

Frontiers in Heat and Mass Transfer, Vol.21, pp. 367-383, 2023, DOI:10.32604/fhmt.2023.042639

Abstract This paper presents a numerical emulation study of heat transmission through tube banks in three-dimensions. Staggered configuration is displayed by fluid dynamics using computer programs (CFD) software (ANSYS fluent). The computer model is used to predict the values of the Nusselt number when changing the values of heat flux and longitudinal pitch. The longitudinal pitch (SL/D) of 1.3, 1.8, and 2.4 mm. The transverse pitch (ST/D) of 1.5 mm, and also considered Reynolds numbers 10000, 13000, 17000, and 190000. The staggered configuration of the tube bundle is demonstrated to investigate the impact of this arrangement on the heat transmission rate… More >

Rodrigo Vidonscky Pinto¹, Flávio Augusto Sanzovo Fiorelli^2,*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 427-443, 2023, DOI:10.32604/fhmt.2023.041917

Abstract The present work provides an experimental and numerical procedure to obtain the geometrical position of the hotspots of a microprocessor using the thermal images obtained from the transient thermal response of this processor subject to pulsating stress tests. This is performed by the solution of the steady inverse heat transfer problem using these thermal images, resulting in qualitative heat source distributions; these are analyzed using the mean heat source gradients to identify the elements that can be considered hotspots. This procedure identified that the processor INTEL Core 2 Quad Q8400S contains one hotspot located in the center of its left… More >

Noureddine Abouricha^1,*, Chouaib Ennawaoui^1,2, Mustapha El Alami³

Frontiers in Heat and Mass Transfer, Vol.21, pp. 523-537, 2023, DOI:10.32604/fhmt.2023.045914

Abstract This work presents a simulation of the phenomena of natural convection in an enclosure with a variable heating regime by the lattice Boltzmann method (LBM). We consider a square enclosure of side H filled with air (Pr = 0.71) and heated from below, with a hot portion of length L = 0.8 H, by imposing a sinusoidal temperature. The unheated segments of the bottom wall are treated as adiabatic, and one of the vertical walls features a cold region, while the remaining walls remain adiabatic. The outcomes of the two-dimensional (2D) problem are depicted through isotherms, streamlines, the temperature evolution… More >