Thermal dissipation enhancement on central impinging jet double layer microchannel heat sinks verified by 3D printing method

The continuous development of electronic chips and devices towards miniaturization and high integration has led to an increase in heat generation, and traditional cooling methods can no longer meet the needs of high-power electronic chips. Based on this background, this study proposes a novel design to improve the thermal performance of microchannel heat sinks for high-performance electronic cooling applications. This double-layer microchannel heat sink with integrated impinging jet and rectangular fins, called impinging jet-nested double-layer microchannel heat sink with rectangular fins (IDN-MHS-RF), is fabricated using Selective Laser Melting (SLM) technology. The design aims to address the limitations of conventional microchannel heat sinks, especially in terms of cooling efficiency under high heat flux conditions. To validate the simulation results, experimental tests were conducted using 3D printed heat sink specimens. Numerical simulations and experimental validation of the expected results agree, confirming the accuracy of the model, and both simulations and experiments show that the IDN-MHS-RF significantly improves the thermal performance when compared to a double-layer straight microchannel heat sink (DSMCHS) and the impinging jet-nested double-layer microchannel heat sink (IDN-MHS). The Reynolds numbers tested ranged from 138.20 to 580.44. The maximum pressure drop of IDN-MHS-RF is 7.33 kPa at Reynolds number 580.44, which is 4.16 and 1.45 kPa higher than that of DSMCHS at 3.17 kPa and IDN-MHS at 5.98 kPa. The introduction of fins and impinging jets enhances the mixing and heat transfer of fluids, which inevitably leads to an increase in the pressure drop, but at the same time, it also significantly improves the thermal performance, with a maximum Nussellt number of 64.44, which is 90.76 % and 27.45 % higher than that of DSMCHS at 33.78 and 50.56 respectively. Its maximum Nusselt number is 64.44, which is 90.76 % and 27.45 % higher than that of 33.78 and 50.56 for DSMCHS and IDN-MHS, respectively. Taking DSMCHS as a reference1, the integrated heat transfer coefficient of IDN-MHS is 1.24, whereas the integrated heat transfer coefficient of IDN-MHS-RF2 is as high as 1.50, which indicates a significant improvement in the overall cooling efficiency compared with DSMCHS and IDN-MHS. In addition, the optimal fin spacing is IDN-MHS-RF2 (rectangular fin spacing of 2 mm), the maximum temperature is only 318.11 K, which is 5.15 and 1.10 K lower than that of DSMCHS and IDN-MHS, respectively, and the maximum temperature difference at the bottom is only 1.22 K, which is 2.11 and 0.54 K lower than that of DSMCHS and IDN-MHS, respectively, so that the cooling effect and thermal uniformity are optimized. The cooling effect and thermal uniformity are optimized, and the relative balance between thermal resistance and flow resistance is realized. These findings show that IDN-MHS-RF can effectively reduce substrate temperature and improve thermal uniformity, highlighting the potential of IDN-MHS-RF to meet the growing demand for thermal management of miniaturized, high-power electronics.