03. Electronics Packaging and Thermal Management

Microchannel cooling is known for effectively managing high heat flux in high-performance computing devices. However, it can lead to increased pressure drop, thereby requiring more pumping power. To tackle this issue, the manifold microchannel heat sink (MMCHS) was introduced, allowing fluid to flow through multiple inlets and outlets simultaneously. This design reduces the fluid travelling path, promoting heat transfer performance with better temperature uniformity compared to the traditional microchannel heat sink (MCHS). This study investigates the thermo-hydraulic characteristics in various manifold microchannel heat sinks, including a reference simple manifold microchannel heat sink (SMMCHS), the diverging bottom-wall manifold microchannel heat sink (DMMCHS), and the stepped bottom-wall manifold microchannel heat sink (StMMCHS). The overall thermo-hydraulic performance of these manifold microchannel heat sinks is compared with that of the traditional microchannel heat sink. Deionized water is used as the working fluid with a total volumetric flow rate ranging from 70 to 210 ml/min. Copper is used as the solid substrate material subject to a uniform heat flux of 50 W/cm² on the bottom surface of the substrate. The results show that all MMCHS configurations significantly reduce the pressure drop by up to 85%, with a 38% reduction in thermal resistance compared to SMCHS. However, the modified MMCHS configurations show similar thermo-hydraulic performance to SMMCHS. For example, at a particular pumping power of 0.0015 W, t the thermal resistance of SMMCHS, DMMCHS, and StMMCHS is reduced by 51.04%, 52.10%, and 52.27%, respectively, compared to SMCHS. Additionally, it is suggested that these modified MMCHS configurations could improve the two-phase flow boiling heat transfer performance compared to SMMCHS, which is the focus of our future research.