Effect of utilizing roughed surfaces within a curved microchannel having cavities on the thermo-hydraulic performance

Abstract

Curved micro-channels with cavities have warranted significant interest from researchers due to their potential to improve the thermo-hydraulic performance of micro-scale hot components. However, there is a scarcity of information concerning the impact of using rough surfaces to such devices for heat transfer enhancement. To this focus, CFD simulations are conducted on a curved micro-channel featuring cavities and different surface roughness without identifying any symmetrical planes. The micro-channel comprises two curved segments, having a hydraulic diameter, Dh, of 0.3 mm. Aluminum serves as a solid material, whereas water functions as a coolant. Reynolds number, varies from 10-800. A constant heat flux of 30 kW/m² is applied. Three cases with varying surface roughness (Ks/D) are analyzed: 0%, 3%, and 9%. The findings indicated that using rough surfaces is helpful for effective turbulence-inducing through boundary-layer disturbing for heat transfer enhancement at low Reynolds number. An enhancement in heat transfer of 22.3% is observed, attributable to the roughness of 9% at Re = 800, compared to the smooth baseline scenario, while the overall performance improved by about 12.2%. Two correlations are developed as a function of Reynolds number and Ks/D for Nusselt and Poiseuille numbers, which are believed to be useful for designers of micro-channels.