Natural convection in a square cavity containing a nanofluid and an adiabatic square block at the center

Abstract The problem of free convection fluid flow and heat transfer of Cu–water nanofluid inside a square cavity having adiabatic square bodies at its center has been investigated numerically. The governing equations have been discretized using the finite volume method. The SIMPLER algorithm was employed to couple velocity and pressure fields. Using the developed code, a parametric study was conducted and the effects of pertinent parameters such as Rayleigh number, size of the adiabatic square body, and volume fraction of the Cu nanoparticles on the fluid flow and thermal fields and heat transfer inside the cavity were investigated. The obtained results show that for all Rayleigh numbers with the exception of Ra  = 10 4 the average Nusselt number increases with increase in the volume fraction of the nanoparticles. At Ra  = 10 4 the average Nusselt number is a decreasing function of the nanoparticles volume fraction. Moreover at low Rayleigh numbers (10 3 and 10 4 ) the rate of heat transfer decreases when the size of the adiabatic square body increases while at high Rayleigh numbers (10 5 and 10 6 ) it increases.

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