Secondary flow through lateral passages to improve hydrothermal performance of liquid-cooled microchannel heat sinks

This study proposes a simple cost-effective concept to improve hydrothermal performance of liquid-cooled microchannel heat sinks utilized in high power density electronics. It consists of parallel microchannels comprising interdigitated cavities on sidewalls interconnected using lateral passages. With suitable misalignment of cavities in adjacent microchannels, secondary flow forms in lateral passages which can improve the heat sink performance. Different cavity shapes are chosen , hydrothermal performances are compared with that of a simple straight-channel heat sink. 3D numerical simulations are performed on a model consisting of a Gallium Nitride substrate as the heat source, a Silicon heat sink , liquid deionized water as the coolant considering temperature-dependent thermophysical properties of Silicon and water. Compared to the base case, heat sink with prismatic cavities and lateral channels has the largest shrinkage of hotspot area and reduces hotspot temperature by 1.6 degrees C at Reynolds number of 160. This configuration enhances the average Nusselt number by 20.2% at the same Re. Moreover, implementing backward cylindrical cavities with lateral channels improves the Coefficient of Performance and Performance Enhancement Factor by 31.7% (at Re=40) and 22.7% at (Re=160), respectively. At the end, performance improvements proposed in the previous works are provided within an itemized review table.

Automated summary

This study proposes a simple cost-effective concept to improve the hydrothermal performance of liquid-cooled microchannel heat sinks. By using parallel microchannels with interdigitated cavities and lateral passages, the heat sink performance is improved with the formation of secondary flow. 3D numerical simulations show that the proposed configurations have significant improvements in hotspot area, hotspot temperature, average Nusselt number, and Coefficient of Performance.