A numerical study on heat transfer performance of microchannels with different surface microstructures

Abstract

Forced convection heat transfer occurring in microchannel is numerically studied in this paper using the CFD (computational fluid dynamics) and LB (lattice Botlzmann) approaches. Simulation results of these two methods are compared and tested against available experimental correlation, and a good agreement is achieved. It suggests that both methods are suitable to describe the liquid flow in microchannels. The influence of microchannel geometric shape on heat transfer performance is investigated by evaluating fluid thermophysical parameter and Nusselt number of the high-temperature surface. It is found that the inflow liquid temperature raises intensively along the flow direction at the entry region, and it develops gradually into equilibrium stage approaching the exit for each microstructure studied in this study. The heat exchange efficiency increases with inlet Reynolds number. The results also imply that the shield-shaped groove microchannel possesses the highest heat exchange performance. Compared with the lowest heat transfer efficiency of the plain surface structure, the averaged Nusselt number can be increased by about 1.3 times. Through the field synergy principle analysis, we find that it is the synergy between temperature gradient and velocity that results in different heat transfer performance for different microstructures.