Thermofluidic analysis of Al2O3-water nanofluid cooled branched wavy heat sink

Abstract

The thermofluidic analysis of Al2O3-water nanofluid-cooled, branched wavy heat sink microchannel (BWHS MC) was carried out for Re = 100–300. The conjugate heat transfer was calculated using ANSYS fluent. The fluid flow is simulated using the RNG k-ε model in the full domain numerical analysis. The phenomenological behaviour of the nanofluid flow through BWHS MC is further studied using numerical results. In comparison, experiments were also performed using a straight channel heat sink microchannel (SCHS MC) of the same hydraulic diameter as the BWHS. The branched wavy microchannel encouraged the secondary flow, thus enhanced the macroscopic mixing. Apart from disruption of the boundary layer and its reinitialization, vortices have been formed near the secondary channel, which improves thermal performance. BWHS reported a higher pressure penalty than SCHS, but the BWHS showed superior performance over SCHS. The heat transfer coefficient is increased at increasing nanofluids concentrations for any given Reynolds number. For the BWHS MC, an enhancement of about 154% of the heat transfer coefficient with a 2% volumetric concentration of nanofluids is achieved at Re = 300 compared to the SCHS MC at similar conditions.