Hot spot mitigating with oblique finned microchannel heat sink

Abstract

Sectional oblique fins are employed in contrast to continuous fins in order to modulate the flow in microchannel heat sink. The breakage of continuous fin into oblique sections leads to re-initialization of boundary layers and generation of secondary flows which significantly enhance the cooling performance of the heat sink. In addition, 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 greater degree of boundary layers redevelopment and secondary flows generation to provide more effective cooling at the high heat flux region. Thus the varying of oblique fin pitch can be exploited for hot spots mitigation. Simulation studies of silicon chip with hot spot shows more than 100% increment in local heat transfer coefficient at the high heat flux region for the variable pitch oblique finned microchannel compared with the conventional microchannel heat sink. Both the maximum temperature and its temperature gradient are reduced by 12.4°C as a result. Interestingly, there is only little or negligible pressure drop penalty associated with this novel heat transfer enhancement scheme in contrast to conventional enhancement techniques. © 2010 by ASME.