LAUSR

Abstract Microchannels with liquid coolants have shown great potential in the high heat flux electronics cooling due to their enhanced heat dissipation capacity. The excessive temperature gradient along the streamwise induces significant thermal mismatch stresses and eventually leads to thermal-mechanical reliability problems in long time service. In this research, a novel variable density alternating obliquely truncated microchannel combined with oblique fin enhancement is proposed to improve the temperature uniformity. The laminar convective heat transfer and flow characteristics for different geometrical configurations are systematically investigated using experimental and numerical analysis. The analysis shows that the enhanced design AOTF-MC increases by up to 63.23% and 111.59% for the Nusselt number and decreases by up to 40.20% and 55.16% for the standard deviation of the temperature compared with the AOT-MC and the RS-MC, respectively. The improved design is also found to have a better overall thermal performance with less pressure drop penalty with a performance evaluation coefficient of 1.6. Furthermore, the variable density layout of the secondary passages significantly improves the temperature uniformity. The results may provide some general design guidelines and concepts of optimization for microchannel heat sinks.