Entropy generation minimization in sinusoidal cavities-ribs microchannel heat sink via secondary channel geometry

Abstract

Microchannel heat sink is an advanced cooling device that can fulfil cooling demand for electronic devices which have high power density in its microchip. However, fast development in electronic industry increases the power density rapidly. As consequence, the conventional design of microchannel heat sink such as Straight channel design (CR MCHS) inadequate to remove the heat flux generated by the electronic device due to thermal resistance and pumping power issue. Thus, in this paper, a novel design is proposed based on theory of entropy generation in laminar forced convection. Entropy generation due to fluid friction and heat transfer in Sinusoidal-cavities-ribs-secondary-channel microchannel heat sink (SD-RR-SC MCHS) was investigated numerically for the Reynold number of 100 – 800 at the constant wall heat flux of 100 W/cm2. Comparative study between proposed design (SD-RR-SC) with related microchannel heat sinks, namely, Rectangular ribs microchannel heat sink (RR MCSH), Sinusoidal cavities microchannel heat sink (SD MCHS) and Sinusoidal-cavities-ribs microchannel heat sink (SD-RR MCHS) was conducted in order to investigate the effect of cavities, ribs and secondary channel geometry on entropy generation augmentation. The result showed that all enhanced microchannel heat sinks obtained augmentation entropy generation number, Ns,a less than 1 for all Re number. Among the enhanced microchannel heat sinks, SD-RR-SC MCHS achieved the lowest Ns,a (0.28) at Re number of 350. Means that, the proposed design (SD-RR-SC MCHS) was less irreversibility compared to the other enhanced microchannel heat sink which contributed to the enhancement of heat transfer performance due to improvement of thermodynamic efficiency.