Numerical investigation of the effects of geometric structure of microchannel heat sink on flow characteristics and heat transfer performance

摘要

A numerical study was performed to investigate the thermal-hydraulic performance of different microchannel heat sink (MCHS) designs for cooling channels in a lithium-ion battery including various geometric modifications. Comparative analysis was performed to determine which design is the best in terms of the heat transfer, the pressure drop, the overall performance and the temperature distribution on the baseline wall. It was observed that local modifications in channels can ensure suitable fluid mixing between core flow and near wall regions; therefore this situation enhances heat transfer performance considerably compared to MCHS with no cavity and rib (MC-NCR). However, the vortices obviously occurred in cavities. Although this phenomenon was helpful for the symmetrical cavity and rib (MC-SCR) in terms of heat transfer enhancement, it was opposite for the asymmetrical cavity and rib (MC-ACR) due to intensive recirculation zones. In addition, the large vortex bubbles especially seen after the last cavity or rib cause pick temperatures because this trapped flow could not be surpassed and carried. Results indicate that as the MC-SCR shows the best thermal performance owing to dominant jetting and throttling effect and convenient longitudinal and transverse vortices, asymmetrical cavity (MC-AC) is the best uniform temperature distribution on baseline wall.