Novel merging and redividing microchannel heat sink system for enhanced heat transfer and reduced flow resistance

The integration of renewable energy sources and high-power electronics requires efficient compact heat exchangers to effectively dissipate the heat generated in a limited space. Microchannel (MC) heat sink structures demonstrate exceptional heat transfer properties. However, their high flow resistance limits their application for larger cooling surfaces. This study proposes a method to reduce flow resistance by periodically merging and redividing MCs in the direction of the cooling medium flow. The design increases the cross-sectional area, reducing resistance and enabling the boundary layer to redevelop. This process compensates for the reduction in convection heat transfer efficiency caused by merging the MCs. The results reveal that for Reynolds numbers ranging between 58 and 175, the heat flux (Q) achieved can be up to 308 kW/m². At water flow rates ranging from 10 to 30 L/h, the flow resistance exhibits an approximately linear relationship with the pressure drop. Additionally, the study examines the mechanisms driving heat transfer enhancement. A goodness factor was used to evaluate the performance of the heat sinks. It was observed that for Reynolds numbers between 58 and 175, the heat transfer area goodness factor falls between 1.14 and 1.12. Adjusting the geometric parameters, such as increasing the height of the MCs and selecting appropriate distributed lengths and widths, significantly enhances the heat transfer performance of the MC. The findings of this study may guide the design of large-scale MC heat sinks to improve heat dissipation efficiency.