Development of a hierarchical microchannel heat sink with flow field reconstruction and low thermal resistance for high heat flux dissipation

Abstract With the development of microelectronics, power density continues to rise, which has put forward higher requirements for the thermal management. At present, the microchannel heat sinks have been investigated as an efficient way for heat dissipation for a long time. However, the optimization of microchannel heat sink is always concentrated on two-dimensional plane structure. In this paper, we proposed a hierarchical microchannel heat sink for heat transfer enhancement. Taking micro pin fin as an example, we designed three different hierarchical pin fins, and the model with the best performance is obtained through simulation under the Reynolds number from 1500 to 5500. The hierarchical heat sink shows better heat transfer performance than traditional heat sink, which is attributed to the flow field reconstruction with no significant increase in pressure drop. Typically, when the upper size (Wp1) of hierarchical pin fin increases to 375 μ m , the maximum Nusselt number reaches 21 with the thermal performance factor up to 1.03 under the Reynolds number of 5500. Experimentally, three sizes of pin fins have been prepared and examined, and the results show that the heat loads exceeding 700 W/cm2 can be dissipated with the maximum temperature rise of 52 K, which is well matched with the simulation results. Anyway, the proposed in this work shows great potential in heat dissipation of electronics.