Hotspot Mitigating With Obliquely Finned Microchannel Heat Sink—An Experimental Study

Abstract

Sectional oblique fins are employed, in contrast to continuous fins, in order to modulate the flow in a microchannel heat sink. The breakage of continuous fin into oblique sections leads to reinitialization of boundary layers and generation of secondary flows that significantly enhance the cooling performance of the heat sink. In addition, an oblique finned microchannel heat sink has the flexibility to tailor local heat transfer performance by varying its oblique fin pitch. Clusters of oblique fins at higher density can be created in order to promote a greater degree of boundary layer redevelopment and secondary flow generation to provide more effective cooling at the high heat-flux region. Thus, the variation of oblique fin pitch can be exploited for hotspot mitigation. Experimental studies of a silicon chip with two hotspot scenarios show that the temperature hike and the temperature difference for the enhanced microchannel heat sink with variable pitch are reduced by as much as 17.1 °C and 15.4 °C, respectively. As a result, temperature distribution across the silicon chip is more uniform. In addition, the associated pressure drop penalty is much smaller than the achieved heat transfer enhancement, rendering it as an effective hotspot mitigating strategy for the single-phase microchannel heat sink.