Detailed thermo-hydraulic investigation of 3D octet lattice structure integrated heat sink

Abstract

The present research work examined the thermo-fluidic characteristics of a heat sink packed with octet-structured periodic metal foam having varying porosity (0.83–0.93) and unit cell lengths (UCL) of 2.5–5 $\mathrm{mm}$ for electronic cooling application. AlSi10Mg material is considered for the octet lattice structure with water as the cooling medium, with the inlet velocity ranging from 0.02 to 0.05 $m/s$ and a steady heat flux of 10 $W/{\mathrm{cm}}^2$ applied at base of the substrate. The effect of the porosity, unit cell length, and inlet velocity on pressure gradient, friction factor, Nusselt number, wall temperature, heat transfer coefficient, and thermo-hydraulic performance parameter is analyzed. Larger pressure gradients are observed for lower values of porosity and unit cell length, with a maximum value of approximately 5000 $\mathrm{Pa}/m$ for the thermal system having 0.83 porosity, 2.5 $\mathrm{mm}$ UCL, and 0.05 $m/s$ inlet velocity. The wall temperature drops with a rise in inlet velocity and a reduction in porosity and UCL, with the lowest value of 311 $K$ for the case of 0.83 porosity, 2.5 $\mathrm{mm}$ UCL, and 0.05 $m/s$ inlet velocity. The case of 0.83 porosity, 5 $\mathrm{mm}$ UCL, and 0.02 $m/s$ velocity was determined as optimum design based on thermo-hydraulic performance parameter.