Flow and heat transfer characteristics and optimization study on the water-cooled microchannel heat sinks with dimple and pin-fin

摘要

Highlights•Microchannel heat sink with dimple and pin-fin is studied and optimized.•Favorable heat transfer augmentation with energy-saving feature is obtained.•Mechanisms of heat and flow fields induced by pin-fin and dimple are revealed.•The maximum increasement ofTPis 10.3% after configuration optimization.•The proposed method can optimize microchannel accurately with less time-consuming.AbstractIn order to develop high-efficiency low-resistance heat exchangers, the heat transfer performance and further optimization of water-cooled microchannel heat sink with dimple and pin-fin were numerically studied in this work. Firstly, the combination effects of structure parameters (diameter of pin-finD1, depth of dimpleδand stream-wise spacingS) on flow structure and heat transfer were investigated in detail. The results show that the proposed designs exhibit heat transfer augmentation with energy-saving and low-resistance features. The increase ofD1and decrease ofSbring out the increase ofNu/Nu0under allRestudied. Flow structures induced by pin-fin make the development of separation flow in the dimple happened in advance. The increase ofD1enlarges the scale and intensity of wake flow of pin-fin, resulting more violent actions of flow on heated walls, then, enhances the heat transfer augmentation. Also, relative smallδwill be beneficial for heat transfer enhancement at lowerReconditions. Furthermore, the automatic calculation configuration optimization analysis by means of pattern search method was validated and conducted successfully to achieve betterTP, and the maximum increasement ofTP, 10.3%, is obtained atRe = 200 as a result. The area of high temperature regions, especially on the side walls, decreases, also, the temperature gradient decreases and the uniformity of heated walls is enhanced. The proposed method can be extended to optimize configuration of microchannel with flow control devices accurately with less time-consuming.