Performance Analysis and Shape Optimization of an Impingement Microchannel Cold Plate

Optimization of liquid-cooled heatsinks (cold plates) is of critical importance due to their widespread application in high-performance electronic packages consisting of heterogeneous integrated systems, field programmable gate arrays (FPGAs), and on-chip hotspots. In this study, the thermo-hydraulic performance of a commercial microchannel impingement cold plate is analyzed in detail. Impingement cold plates are preferred over parallel flow cold plates due to their lower pressure drop where there is no restriction on space (i.e., where flow can enter perpendicular to the electronic board). Splitting the flow into two branches cuts the flow rate and the path into half, which leads to a lower pressure drop through the channels. Since the fins of the present commercial cold plate (considered as the baseline design) are tilted, the effect of the fin tilt angle on the hydraulic and thermal performance of the cold plate is also studied. The response surface method (RSM) is used to optimize the geometry of the fins and impinging inlet. The results of optimization show that hydraulic resistance can be reduced by 50% without a remarkable change in thermal resistance. The effect of the geometric parameters on the cold plate thermo-hydraulic performance is studied using the computational fluid dynamics results at the RSM design points. The variation in the cold plate coefficient of performance with the coolant flow rate and inlet temperature is compared for the baseline design and a selected optimal design. Finally, the effect of impinging inlet geometry on the chip temperature profile is also examined.