High performance heat sink with counter flow diverging microchannels

Effective thermal management of high-power electronics is urgently demanded for the further development of electric vehicles. Two-phase flow boiling in microchannels is well recognized as a prominent approach for high density heat dissipation. This study develops a novel high performance heat sink with counter flow diverging microchannels to further enhance the flow boiling performance. A unique and significant heat exchange between the neighboring channels is demonstrated to dramatically alter the flow pattern transition in the counter-flow microchannel manifold. In particular, as the flowing bubbles in the microchannels can shrink or even disappear before exiting, no back flow or partial dry-out is observed throughout all the tested conditions. Therefore, this additional heat transfer mechanism in the present design enables significant enhancement of temperature uniformity, up to a heat flux of 2677 kW·m⁻² with 45.1% increment of heat transfer coefficient, 73.8% reduction of pressure drop and 123.1% increment of coefficient of performance when compared with those of traditional co-current flow design. Overall, with the excellent flow boiling performance, the present study offers a highly promising microchannel design for a variety of applications requiring high heat flux dissipation.