Free convective flow of nanofluid having two nanoparticles inside a complicated cavity

摘要

In this paper, free convective flow and thermal behaviors of nanofluid inside a complicated enclosure is investigated. The cavity consists of a centered heated diamond shaped hollow obstacle. The vertical walls are constantly and uniformly less heated than the obstacle. The base surface of the cavity is insulated perfectly. The upper horizontal part of the enclosure is surrounded by solid material with constant thermal conductivity. The upper boundary of this solid region is considered as adiabatic. The working fluid is water based nanofluid having two nanoparticles alumina and copper. The integral forms of the governing equations are solved numerically using Galerkin's Weighted Residual Finite Element method. Computational domains are divided into finite numbers of body fitted control volumes with collocated variable arrangement. Results are presented in the form of average Nusselt number (Nu), average temperature (θ_(av)), mean velocity of the nanofluid (V_(av)), mid height horizontal and vertical velocities for a selected range of convective parameter Rayleigh number Ra (10~3 - 10~6) and viscosity parameter Pr (4.2 - 8.8). Streamlines and isothermal lines are also displayed for the above mentioned parameters. The results indicate that the highest Nu is found for both greatest Ra and Pr.