Comparative study on hydrothermal characteristics in straight, divergent and convergent minichannels having ribs with various heights along-channel

Abstract

The rapid development of high heat flux devices brings greater challenges to the cooling performance and wall temperature uniformity of Micro/mini-channel heat sink (MCHS). Using micro/mini-channel with various flow passages or ribs is an effective technology for performance improvement in MCHS. However, it is not clear that the hydrothermal performance of the micro/mini-channels with the combination of various flow passages and ribs. Thus, a comparative study on the hydrothermal characteristics in straight, divergent and convergent minichannels having ribs with various heights along-channel are analyzed numerically at inlet mass flow rate of 0.2–0.8 g/s. Three kinds of rib height arrangements are considered, including variable rib heights from low to high, variable rib heights from high to low, and uniform rib height. The results show that convergent minichannel having ribs with rib heights from low to high achieves the best wall temperature uniformity. Divergent minichannel having ribs with rib heights from low to high presents the smallest pressure drop in all minichannels with ribs. Divergent minichannel having ribs with uniform rib heights shows the lowest thermal resistance and the highest heat transfer coefficient, and this minichannel yields the highest comprehensive performance with the maximum comprehensive heat transfer factor of 1.39 at high mass flow rate.