Thermo-hydraulic performance evaluation of radial tree-branching microchannel heat sinks for electronic cooling applications

Abstract

The fractal-like tree-branching microchannel heat sink (TB-MCHS) can be a potential solution for the cooling of electronic devices due to its ability to dissipate high heat flux and maintain uniform temperature distribution on the chip surface while requiring lower pumping power compared with the conventional TB-MCHS with constant channel depth. This work proposed a novel design of radial TB-MCHS with continuously varying, either increasing or decreasing, channel depth from the centre inlet to the radial outlet, resulting in different fluid volumes in channels compared to the conventional constant channel height TB-MCHS. A three-dimensional numerical model is developed and validated with in-house experimental results to study the thermo-hydrodynamic performance and entropy generation of the TB-MCHSs. The results reveal that the proposed designs of TB-MCHS with different fluid volumes negligibly enhance the heat transfer coefficient and significantly reduce the pressure drop and pumping power requirement compared to that of constant fluid volumes. The TB-MCHS with continuously increasing channel depth (TB-MCHS-DIV) exhibits the lowest pressure drop, thermal resistance, substrate temperature, and entropy generation among all the designs of TB-MCHS considered. However, the TB-MCHS-DIV shows the lowest convective heat transfer coefficient and higher coefficient of performance (COP) and heat removal rate than the TB-MCHS-ST. Further, it is found that the TB-MCHS-DIV can be performed better than TB-MCHS-CON and TB-MCHS-ST at constant pumping power.