Forced convection heat transfer for swaged mixed metal heatsinks

This paper is an experimental investigation comparing the thermal performance of four heatsink combinations based on the forced convection heat transfer mode. The four designs consist of an all Aluminum, all Copper, Copper baseplate/Aluminum fin and Aluminum baseplate/Copper fin heatsink. Each heatsink was placed within a vertical wind tunnel of Plexiglas walls such that the fins were positioned vertically and parallel to the airflow inside the tunnel. A block heater providing 585 watts and covering 5% of the baseplate was attached to each heatsink. Experiments were performed for a Reynolds number ranging from 720 to 3200. This Reynolds number was based on the fin spacing. The average rise in temperature of ten measured locations was used to calculate the thermal resistance. The all Copper heatsink provided the lowest thermal resistance while the all Aluminum heatsink returned the highest value. The Copper-Base/Aluminum-Fin and Aluminum-Base/Copper-Fin heatsinks showed very similar thermal resistance results for identical approach velocities. The pressure drop through the Copper fin heatsink was found to be higher than through the Aluminum fin heatsink. For small heat source coverage, the experiments show that there is an increase in the performance of the Copper-Base/Aluminum-Fin heatsink due to the higher conductivity of the Copper base. The experiments show that this performance can be matched by increasing the thermal conductivity of the fin material instead, as in the case of the Aluminum-Base/Copper-Fin heatsink.