Thermal Simulation of the Symmetric and Asymmetric Arrangement of Barriers on Heat Transfer Enhancement in a Porous Gas Heat Exchanger

In this paper, affecting parameters of porous medium to improve the rate of convective heat transfer in a two-dimensional porous gas heat exchanger (PGHE) for two arrangements (symmetric and asymmetric) of barriers are numerically investigated. Two barriers have been located on the top and bottom walls and one obstacle was placed in the central zone of the PGHE. In the present study, solving the momentum and energy equations has been done by Lattice–Boltzmann method with multiple-relaxation-time (LBM-MRT). The boundary conditions in both arrangements include the left and right walls which are kept at the cold constant temperature and both top and bottom walls are insulated. There is a volumetric heat source within the PGHE. The temperature of barriers and fixed obstacle are kept at hot temperature. In this study, impact of effective parameters in porous medium and heat transfer including dimensionless number of Darcy, porosity, and Rayleigh number on the flow and temperature fields has been investigated. According to the numerical results, it has been shown that the porous medium and barriers cause increase and improvement in the heat transfer within PGHE in both symmetrical and asymmetrical arrangements. The results also demonstrate that as dimensionless Darcy number increases, more convection occurs within the chamber. Examining arrangement of barriers shows that in asymmetrical arrangement, more space appears in chamber and convective heat transfer is done better.