Numerical Investigation of Heat Transfer in Open Microchannel Heat Sinks With Transverse Ribs for High Heat Flux Dissipation

As one of the key components of the nuclear fusion reactor, the target of divertor directly faces huge heating power from fusion plasma, and thus its capability to withstand high heat flux is of essential importance for the stability and safety operation of fusion devices. The divertor target needs to meet the heat dissipation requirements of up to 20 MW/m2 heat loads in future fusion reactors. Herein, we proposed an open microchannel heat sink with transverse ribs (OMHS-TR) to enhance the heat transfer of W/Cu flat-type mock-ups. The fluid flow and heat transfer characteristics of OMHS-TR were numerically investigated, and the effect of the number of transverse ribs (TR) was studied under the operational conditions with a mass flux of 30 L/min and a heat flux of 20 MW/m2. The numerical results demonstrated that OMHS-TR shows significant enhanced heat transfer performance with 19.6 K reduction in average wall temperature, 30.6 K reduction in maximum surface temperature, and ~ 44% increment of Nusselt number when compared with those of open microchannels without TR. However, TR also leads to high-flow disturbances and blocking-flow effect, which increases the pressure drop. The heat transfer coefficient and pressure drop of OMHS-TR increase with the increase in the number of TR. This study may provide some insights for high heat flux dissipation on the target plate of the divertor.