CFD simulation of microchannel heat exchanger using COMSOL software for waste heat recovery

Heat exchangers are among the most widely used equipment in the industry, which is of special importance as well as heat exchangers account for a large share of energy consumption in the industry. Study of heat exchangers according to the type of their use in different industries can in turn lead to the correct choice of the heat exchanger. This correct choice reduces energy consumption due to the operation of those heat exchangers. Among heat exchangers, micro-heat exchangers have a high efficiency compared to other heat exchangers. So, the study of heat exchangers is of special importance. Using COMSOL software, a micro-heat exchanger was simulated and the results were compared with the experimental data. The results of the simulation are in good agreement with the experimental data. A simulated heat exchanger consists of an upper and a lower plate. In the lower plate, ۲۳ channels are designed for air entry and in the upper plate, ۳۵ channels are designed as two passages for oil entry. Hot air and cool oil enter the lower, and upper plate channels, respectively. The results of the simulation showed that the outlet temperature of the channels in the oil and air parts is very close to the laboratory data. It must be stressed that in the simulation mode the output velocity and profiles are very close to the experimental data. Simulation results showed that the velocity profile obtained by the software was the same as the analytical profile. Also, the rate of heat transfer in the air duct from the right to the left side is increasing. This is due to the low temperature in the upper plate of the micro-heat exchanger.

Keywords:

Microchannel heat exchanger , Simulation , Heat transfer , Fluid mechanics , COMSOL , Energy recovery