Experimental investigation of thermo-convection behaviour of aqueous binary nanofluids of MgO-ZnO in a square cavity

Abstract An innovative way of advancing thermo-convection performance of thermal management systems is the application of binary nanofluids (BNFs) as thermal working fluids. This paper experimentally investigated for the first time the thermo-convection behaviour of MgO-ZnO nanoparticles dispersed in deionised water (DIW) for concentrations of 0.05 vol.% and 0.1 vol.% at percentage weight ratios (PWRs) of 20:80, 40:60, 60:40, 80:20 (MgO-ZnO) in a square cavity. Several parameters such as Ra, Nuav, hav, and Qav at different temperatures gradients (20°C to 50°C) were investigated. Viscosity and thermal conductivity of the BNFs and DIW were experimentally obtained for the studied temperatures. Temperature gradient and PWRs of hybrid nanoparticles in the BNFs were noticed to enhance Nuav, hav, and Qav. In addition, maximum enhancement achieved were 72.6% (Nuav), 76.01% (hav), and 72.2% (Qav). The use of BNFs in a square cavity proved to yield good enhancement for thermo-convection performance. A new model linked to φand PWRs has been introduced to predict Nuav. The novel outcomes of this study further corroborate the synergetic advantage of using BNFs over NFs.