Numerical study on heat transfer and flow characteristics of novel microchannel heat sinks

The microchannel cooling technology is an effective method to solve heat dissipation problems caused by high heat flux devices. In this study, microchannel heat sinks imitating Tesla valve (MCTV), mounted with sector bump (MCSB) and diamond bump (MCDB) were designed. Compared to the straight microchannel with the same heat transfer area, the heat transfer and flow characteristics (Nu, f and performance evaluation criterion PEC) of three innovative microchannel heat sinks were investigated numerically. The results show that Nu of MCTV, MCSB and MCDB are increased by 102.3%, 111.2% and 94.8% while f of these structures is increased to 3.21 times, 3.14 times and 2.81 times with Re of 800, respectively. The PEC of three novel microchannels were bigger than that of the straight microchannel. It can be attributed to the flow separation and convergence caused by the innovative structure, which resulting in the periodic interruption and redevelopment of the thermal boundary layer to promote momentum and energy exchange of fluid inside and outside the boundary layer. Due to the largest PEC, the effects of geometric parameters on the thermal performances of MCSB were further analyzed. It shows that the Nu of MCSB increases with the increase of sector bump angle θ and the decrease of arc radius r. The T_max of MCSB is below 70 °C with r of 1.4 mm and θ of 15° when Re ≥ 700, which is suitable for heat dissipation application of electronic devices.