Quanfu Gao^a,b , Kun Zhang^a,b,*, Liang Bi Wang^a,b

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-10, 2020, DOI:10.5098/hmt.14.29

Abstract Detailed numerical analysis is presented for natural convection heat transfer in internally finned horizontal annuli. Governing equations are discretized using the finite volume method, and solved using SIMPLE algorithm with Quick scheme. The results show that the flow and heat transfer can reach steady state when the Rayleigh number is below 2×10⁴. When the Rayleigh number is greater than 3×10⁴ , two different types of numerical solutions under the same parameters can be obtained for different initial conditions. The critical Rayleigh numbers with two different initial conditions are different from steady to unsteady solutions. The oscillatory flow undergoes several bifurcations… More >

Changming Ling^a,b,*, Yin Zhong^a,b

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-6, 2020, DOI:10.5098/hmt.14.25

Abstract Effects of serrated pulsating airflow on liquid film evaporation in a falling film channel was numerically studied based on a two-dimensional model. The mechanism of pulsating airflow evaporation was studied as the pulsating airflow swept across the vertical liquid film surface at the stagnant temperature. Effects of amplitude, frequency, and velocity of the serrated pulsating airflow at certain evaporation time on evaporation were analyzed. Compared with the uniform airflow, the highest relative evaporation of liquid film on vertical pipe inner surface was increased by about 0.3 %. When the airflow was pulsating, the cycle of vapor mass flow rate was… More >

Zhiyun Wang^† , Zixuan Zhou, Mo Yang

Frontiers in Heat and Mass Transfer, Vol.14, No.1, pp. 1-7, 2020, DOI:10.5098/hmt.14.13

Abstract Double diffusive natural convection in an open cavity under the Soret and Dufour effect is simulated numerically. The influences of different Rayleigh numbers (range from 103 to 107), Lewis numbers (range from 0.5 to 8), buoyancy ratios (range from -5 to 5) and Soret and Dufour (range from 0 to 0.5) on the flow field, temperature and concentration distributions, as well as on the variation of the average Nusselt number and the average Sherwood number are investigated. The result shows that, when buoyancy ratios is -1, the average Nusselt number and the average Sherwood number reaches the minimum, namely the… More >

Pengda Li, Chao Xu, Zhirong Liao^* , Xing Ju, Feng Ye

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-10, 2020, DOI:10.5098/hmt.15.10

Abstract This study numerically investigates the charging and discharging processes of a three-stages cascaded latent heat thermal energy storage unit using three molten salts as the phase change materials (PCMs). Each stage of the unit is a vertical shell-and-tube heat exchanger, whose shell side is filled with the PCM and air. The liquid fractions, temperatures, and accumulated thermal energy of the PCMs during the fully charging and discharging processes, as well as the effects of the HTF inlet temperature, are analyzed. The results show that lower melting temperature of the PCM causes faster charging rate and more released heat in the… More >

Xiaoyong Gu^*, Guohe Jiang, Yang Wo, Biwen Chen

Frontiers in Heat and Mass Transfer, Vol.15, No.1, pp. 1-8, 2020, DOI:10.5098/hmt.15.3

Abstract The heat transfer characteristics of propylene glycol-water (PG-W) mixture with different concentrations in shell side of spiral wound heat exchanger (SWHE) with different geometric parameters were studied numerically. Experiment was carried out and the average difference between the simulated results and the experimental results was 5.3%. The simulation results show that heat transfer coefficient increases with the increase of center core diameter and longitudinal spacing of tubes, but decreases with the increase of tube outer diameter. The center core diameter and tube outer diameter have greater effects on heat transfer performances at higher concentration. Economic index was established and found… More >

Tohid Adibi¹, Shams Forruque Ahmed^2,*, Omid Adibi³, Hassan Athari⁴, Irfan Anjum Badruddin⁵, Syed Javed⁵

Intelligent Automation & Soft Computing, Vol.37, No.1, pp. 147-163, 2023, DOI:10.32604/iasc.2023.035392

Abstract Heat exchangers are utilized extensively in different industries and technologies. Consequently, optimizing heat exchangers has been a major concern among researchers. Although various studies have been conducted to improve the heat transfer rate, the use of a wavy wall in the presence of different types of heat transfer mechanisms has not been investigated. This study thus investigates the mixed heat transmission behavior of fluid in a horizontal channel with a cavity and a hot, wavy wall. The fluid flow in the channel is considered laminar, and the governing equations including continuity, momentum, and energy are all solved numerically. The numerical… More >

Rongge Xiao^a,*, Shuaishuai Jin^a, Xin Feng^b, Peng Zhang^c, Zheng Dai^c

Frontiers in Heat and Mass Transfer, Vol.16, No.1, pp. 1-7, 2021, DOI:10.5098/hmt.16.25

Abstract With the increasing production and use of natural gas, the supersonic nozzle has become focus of the impurity removal research. In this paper, the modified classical nucleation model is used as the condensation nucleation model, and the Gyarmathy growth model is selected as the droplet growth model. Based on the assumption of no phase slip and Eulerian two fluid model, the flow control equation of wet natural gas is established. By giving the selection criteria as a turbulence equation, the SRK real gas equation is used to carry out the corresponding numerical simulation. The required supersonic nozzle structure and grid… More >

Ming Zhao^*, Yuhao Zheng

Frontiers in Heat and Mass Transfer, Vol.16, No.1, pp. 1-9, 2021, DOI:10.5098/hmt.16.19

Abstract The performance optimization of the triangular-tube phase change heat accumulator is carried out from three aspects. The first is to compare with three different types tubes: the traditional round tube, the square tube, and the elliptical tube. Results show that equilateral triangle tube has the best heat storage and release characteristics. The second is to study the sub-cavity heat accumulator model based on multiphase change materials on the basis of the triangular tube. The third is to study the turn-over triangular tube heat accumulator. Both the flip function through discrete point fitting and the best reversal time are obtained. More >

Olanrewaju M. Oyewola^a,b,*, Samuel I. Afolabi^b , Olawale S. Ismail^b

Frontiers in Heat and Mass Transfer, Vol.17, No.1, pp. 1-8, 2021, DOI:10.5098/hmt.17.11

Abstract The problem of natural convection in rectangular cavities with different aspect ratios has been numerically analyzed in this study. Cavities considered have their right vertical walls heated and cooled at the opposite with constant temperatures, while horizontal walls are kept adiabatic. The objective of this study is to ascertain the significant effects of Rayleigh numbers (Ra), Nusselt numbers (Nu) and aspect ratios (AR) on flow and heat transfer in rectangular cavities. The equations of Navier-Stokes and energy are solved by applying Galerkin weighted residual Finite Element Method. Parametric calculations are performed for Rayleigh numbers (Ra) ranging from 104 to 108… More >

Zhiyun Wang^*, Ziqing Wang, Mo Yang

Frontiers in Heat and Mass Transfer, Vol.17, No.1, pp. 1-7, 2021, DOI:10.5098/hmt.17.10

Abstract This paper presents a two-dimensional fluid-structure interaction numerical simulation of fluid flow over two horizontal heat exchange cylinders affected by a flapping reed in a domain. The reed is a thin flexible sheet made of elastic material with one end fixed on the trailing edge of the upstream cylinder. The effects of the reed length and the cylinder spacing on the periodic oscillations of the reed, the flow field and the heat transfer of the downstream cylinder. The results show that the oscillation of the reed in this paper is a single-period oscillate model. Compared to the case of cylinder… More >