Novel Tree Branching Microchannel Heat Sink Under Variable and Constant Fluid Volume Approaches

In this work, two designs of radial tree branching microchannel heat sinks (TB-MCHSs) are proposed: (i) TB-MCHS with continuously increasing channel depth from the centre inlet to the radial outlet (TB-MCHS-DIV) and (ii) TB-MCHS with continuously decreasing channel depth (TB-MCHS-CON). Thermo-hydrodynamic performance of TB-MCHS-DIV and TB-MCHS-CON is numerically evaluated and compared with TB-MCHS with constant channel depth (TB-MCHS-ST). The present work is carried out in two scenarios: In the first scenario, the fluid/channel volumes of TB-MCHS-DIV and TB-MCHS-CON are significantly more than TB-MCHS-ST, whereas in the second scenario, the same is nearly equal to that of TB-MCHS-ST. The results reveal that in the second scenario compared to TB-MCHS-ST, the proposed design shows slightly higher (~ 3%) average heat transfer coefficient, whereas it also shows higher (~ 7%) pressure drop. However, in the first scenario, the proposed design shows lower (~ 8%) average heat transfer coefficient than the TB-MCHS-ST, whereas it also shows lower (27%) pressure drop. The substantial reduction in the pressure drop dominated the reduction in heat transfer coefficient resulting in the performance evaluation criteria (PEC) value more than unity for the proposed design based on the variable fluid volume approach.