Dave Martin^a,b,† , Hicham Chaouki^a,b, Jean-Loup Robert^a, Donald Ziegler^c, Mario Fafard^a,b

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.31

Abstract The two dimensional phase change problem was solved using the extended finite element method with a Lagrange formulation to apply the interface boundary condition. The Lagrange multiplier space is identical to the solution space and does not require stabilization. The solid-liquid interface velocity is determined by the jump in heat flux across the i nterface. Two methods to calculate the jump are used and c ompared. The first is based on an averaged temperature gradient near the interface. The second uses the Lagrange multiplier values to evaluate the jump. The Lagrange multiplier based approach was shown to be more robust… More >

A. Zoubir^a , R. Agounoun^a,*, I. Kadiri^b, K. Sbai^a , M. Rahmoune^a

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-6, 2016, DOI:10.5098/hmt.7.35

Abstract Boiling heat transfer process is important because it is a way to increase the flux density transmitted at low temperature differences. To quantify the thermal exchanges, we performed an experimental study of the nitrogen pool boiling, in transient conditions, on a horizontal brass ribbon for a fixed flux density. The results show that there is no break between the monophasic convection zone and the nucleated boiling region. In the nucleated boiling zone, the temperature variations are very small. We also note that the overheating required to trigger boiling increases with the time delay after the activation of nucleation sites. More >

Dave Martin^a,b,† , Hicham Chaouki^a,b, Jean-Loup Robert^a, Donald Ziegler^c, Mario Fafard^a,b

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-11, 2016, DOI:10.5098/hmt.7.40

Abstract A two phase model for two-dimensional solidification problems with variable densities was developed by coupling the Stefan problem with the Stokes problem and applying a mass conserving velocity condition on the phase change interface. The extended finite element method (XFEM) was used to capture the strong discontinuity of the velocity and pressure as well as the jump in heat flux at the i nterface. The melting temperature and velocity condition were imposed on the interface using a Lagrange multiplier and the penalization method, respectively. The resulting formulations were then coupled using a fixed point iteration a lgorithm. Three examples were… More >

Dave Martin^a,b,† , Hicham Chaouki^a,b, Jean-Loup Robert^a , Donald Ziegler^c , Mario Fafard^a,b

Frontiers in Heat and Mass Transfer, Vol.10, pp. 1-11, 2018, DOI:10.5098/hmt.10.18

Abstract A model for two dimensional solidification problems including convection was developed by coupling the Stefan problem with the Stokes problem. The extended finite element method (XFEM) was used to capture the strong discontinuity in velocity and pressure as well as the jump in heat flux at the phase change interface. The melting temperature and no-slip condition were imposed on the interface using a Lagrange multiplier and the penalization method, respectively. The resulting formulations were then coupled using a fixed point iteration algorithm. The model was able to reproduce the benchmark simulations while maintaining a sharp phase change interface. More >

B. Orr^a,* , R. Singh^a, T. L. Phan^a , M. Mochizuki^b

Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.1

Abstract One of the problems with cooling an IGBT inverter chip is that its heat generation is not constant. These chips tend to produce heat in pulses which results in high peak chip temperatures. Transient modelling is required to determine the suitability of a heat sink and to ensure the max peak temperature is not exceeded. This paper demonstrates a method of transient thermal analysis using a thermal resistance / capacitor network. A sample heat sink was modelled and then experimentally tested to validate the model. A novel method of modelling phase change materials (PCM) using the thermal resistance / capacitor… More >

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

Frontiers in Heat and Mass Transfer, Vol.15, 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 >

Ming Zhao^*, Yuhao Zheng

Frontiers in Heat and Mass Transfer, Vol.16, 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 >

Kapil Dev Choudhary, Shyam Sunder Yadav^† , Mani Sankar Dasgupta

Frontiers in Heat and Mass Transfer, Vol.16, pp. 1-10, 2021, DOI:10.5098/hmt.16.14

Abstract In the current work, we simulate the condensation of supercritical CO₂ during its high speed flow inside two different converging-diverging nozzles. We use the homogeneous equilibrium method and the classical nucleation theory based non-equilibrium phase change model for this purpose. The simulation results indicate significant influence of the nozzle inlet condition, nozzle shape and the fluid thermophysical behaviour on the nonequilibrium conditions prevailing inside the nozzles. We observe very low, ∼0.15 K, supercooling for the flow of CO₂ inside the Claudio Lettieri nozzle compared to the supercooling of ∼3 K observed for the Berana nozzle. Very high nucleation rate (∼… More >

Kun Zhang^a,b,* , Zhiyong Li^a,b, Jia Yao^a,b

Frontiers in Heat and Mass Transfer, Vol.19, pp. 1-8, 2022, DOI:10.5098/hmt.19.5

Abstract Detailed numerical analysis is presented for heat transfer characteristics of charging or discharging process in phase change thermal energy storage unit with inner corrugated tube. The results indicated that the charging or discharging rate of phase change material (PCM) for the case of inner corrugated tube is obviously higher than that in unit with inner plain tube due to the increasing heat transfer surface. The heat transfer rate increase with the increasing mass flow rate. However, when the mass flow rate of heat transfer fluid (HTF) is greater than 0.0315kg/s, the charge and discharge time can not be obviously shorten… More >

Xiaoyong Gu^a,*, Gang Wu^b, Biwen Chen^c

Frontiers in Heat and Mass Transfer, Vol.20, pp. 1-9, 2023, DOI:10.5098/hmt.20.24

Abstract To maintain the maximum temperature and temperature difference of batteries in electric vehicles within a reasonable range, a battery thermal management system combining closed air-cooling with phase change material(PCM) is proposed and investigated. A three-dimensional numerical model is developed and validated by experiment. The results indicate that the temperature rise of batteries decreases with the increase of ambient temperature. The increasing filling amount of PCM reduces the maximum temperature difference of batteries as well as the effect of the airflow rate on maximum temperature of batteries. The energy consumption is minimum when the filling amount of PCM is 0.28kg. More >