Performance and Integration Implications of Addressing Localized Hotspots Through Two Approaches: Clustering of Micro Pin-Fins and Dedicated Microgap Coolers

An evaluation of two approaches to localized hotspot cooling is conducted through both numerical modeling and experimental demonstration, with the advantages and limitations of each approach highlighted. The first approach, locally increasing the density of pins in a micro pin fin heat sink, was shown through numerical modeling to deliver a factor of two enhancement in effective heat transfer coefficient by doubling the pin density near the hotspot. This simpler approach to maintaining temperature uniformity eliminates the need for hotspot specific fluid routing and delivery, and also has minimal impact on the larger flow field. Dedicated hotspot coolers, on the other hand, have the ability to dissipate significantly larger heat fluxes while maintaining manageable pressure drops, because the flow rate to the dedicated cooler can be closely matched to the demands of the hotspot. Dissipation of hotspot heat fluxes in excess of 2 kW/cm² is demonstrated experimentally using a two phase dedicated hotspot cooler. However, dedicated coolers require additional fluidic routing and manifolding to efficiently deliver the coolant to the hotspot. These integration concerns are considered in concert with the performance of the hotspot cooler itself to enable better informed thermal design for both system level and device level cooling.