Buoyancy-driven flow and heat transfer in a nanofluid-filled enclosure

Abstract

Numerical study of buoyancy-driven laminar incompressible flow in a 2D rectangular enclosure utilizing copper–water nanofluid has been investigated. Constant heat flux at the left vertical wall while convective boundary condition on the other three walls has been investigated for three different Rayleigh numbers (1 × 105 to 3 × 105) based on the incoming solar heat flux value. Three aspect ratios (AR = H / L where H and L are the height and length of the enclosure, respectively) 0·5, 1·0 and 1·5, three inclination angles α (from the horizontal) 0, 20 and 37° for solar panel, nanoparticle concentration ϕ (varying upto 6%), Prandtl number (Pr = 7·0) for water has been kept constant and Nusselt number (Nuknf) based on the heat-transfer coefficient has been considered in the present study. Increment in average Nusselt number has been observed with increment in Rayleigh number and inclination angle. At low aspect ratio, maximum average Nusselt number has been found. Flow structures are sensitive to solid-particle concentration value, and average Nusselt number increases with solid-particle concentration value. A decrement in average Nusselt number at Ra = 3 × 105 for aspect ratios of 0·5 and 1·5 has been observed.