Thermal and entropy analysis of a manifold microchannel heat sink operating on CuO–water nanofluid

Abstract

An increase in area and disturbance of flow by introducing ribs in a microchannel system has proven to be effective in thermal management. On the other hand, nanofluid as a new coolant could also provide a much-needed performance boost. The performance of a manifold microchannel heat sink utilising nanofluid as the coolant and ribs for flow mixing has been investigated. The study is conducted with CuO–water nanofluid, Reynolds number of 100–400 and CuO nanoparticle volume fraction up to 4%. The results show that CuO–water nanofluid produced a higher thermal performance at higher concentration and Reynolds number with a corresponding increment in pressure drop. When compared to water, the Nusselt number increased from 4.4 to 23.67% at Reynolds number of 100 and CuO concentration of 4%. The addition of ribs on the sidewall of the manifold microchannel only showed a slight enhancement of up to 6.8% in the Nusselt number. Similarly, the thermal enhancement factor ranging from 1.03 to 1.07 is observed for the ribbed manifold microchannels, indicating better overall performance when compared to the microchannel without ribs.