Air Flow Inversion for Enhanced Electronics Cooling in Additively Manufactured Air Channels

Abstract

In this study, CFD analysis and experimental validation of additively manufactured air cooling channels with enhanced heat rejection through flow inversion was investigated for use in a medium voltage solar inverter. Design methodology implemented revolved around flow isolation in channel groupings divided vertically in orientation to the heat source. By interchanging the flow paths of the top and bottom groups of channels halfway through the length of the channel, relatively cooler air is allowed to flow over the heat source contact region on the back end of the channel. Preliminary CFD analysis was performed, and two designs demonstrating the greatest enhancement of heat removal, as well as a comparable straight channel design for comparison, were manufactured from AlSi10Mg powder using direct metal laser sintering. Experimental validation was performed using a custom air channel to deliver consistent flow conditions with ceramic AC strip heaters providing thermal dissipation into the channel. Thermal profiles were determined through temperature readings taken with type-K thermocouples at key locations on the channel and flow path. Flow inversion channels showed reduced thermal gradients across the simulated dies, over the straight channel design. However, this enhancement of heat removal comes at the cost of additional pressure drop.