A review on thermal performance enhancement techniques in microchannel heat sink. 2019-01-0907
Overheating of power electronics devices has become the notable issue due to their continued compactness and increased heat flux that needs to be dissipated. Microchannel heat sink (MCHS) is considered as a prominent cooling scheme for high power microelectronics devices. This paper reviews some techniques implemented for the enhancement of heat transfer in the microchannel for both single phase (liquid and gas) and two-phase (boiling and condensation) systems. Heat transfer can be enhanced by using Tapered microchannel which promotes early turbulence at lower Reynolds number, by decreasing height and increasing the number of the transverse microchannels and it is more noticeable for narrower transverse microchannel. Other useful techniques in thermal performance enhancement are use of Convex dimples which also demonstrates very less pressure drop, use of pulsating flow rate, breaking up of boundary layer at entrance region, micromachining the channel walls with streamwise spiral grooves, disrupting and restoring the thermal boundary layer, increasing mainstream turbulence in MCHS with triangular cavities and rectangular ribs or by using ferrofluids (magnetic nanofluids) . Heat transfer enhancement by means of nanofluids has gained rapid popularity in last decades. In various cases, the addition of different volume fraction of nanoparticles leads to an increase in heat transfer coefficient, the thermal conductivity of the base fluid is also increased by increasing the volume concentration of nanoparticles. Application of a magnetic field on microchannels show significant improvement in Nusselt number. This explanatory review article is expected to help in understanding the research innovations towards thermal performance enhancement in MCHS.