Experimental hydrothermal behavior of hybrid nanofluid for various particle ratios and comparison with other fluids in minichannel heat sink

Abstract

The effect of the particle mixture ratio in hybrid nanofluid on minichannel heat sink performance is analyzed experimentally. The heat sink, made of aluminium, contains nine parallel rectangular minichannels having cross section of 1 mm × 3 mm with 30 mm length. Total 0.01% volume concentration of Al2O3 and MWCNT nanoparticles for various mixing ratios (10:0, 8:2, 6:4, 4:6, 2:8 and 0:10) is used to synthesize water-based hybrid nanofluids. Different parameters as volumetric flow rate (0.17–0.5 LPM), fluid inlet temperature (20–40 °C) and heat flux (8.3 W/cm2) are considered. Present Al2O3-MWCNT hybrid nanofluid is compared as well with hybrid nanofluids available in literature based on both thermophysical-transport and hydrothermal properties. Heat transfer coefficient, Nusselt number, pressure drop and friction factor increase with an increase in MWCNT fraction in hybrid nanofluid. Maximum heat transfer coefficient and pressure drop increments are 44.1% and 68.1%, respectively, for MWCNT nanofluid. Inlet fluid temperature has a negative effect on pressure drop and positive effect on heat transfer coefficient. Nusselt number to friction factor ratio is observed maximum at 6:4 mixing ratio of Al2O3 and MWCNT. Al2O3 + MWCNT (optimum mixing ratio of 6:4) hybrid nanofluid is found better as compared to existing hybrid nanofluids at total volume concentration of 0.01%.