Effects of Inclination Angle on Mixed Convection Heat Transfer of a Nanofluid in a Square Cavity

Abstract

In this work, effects of inclination angle and nanoparticle concentration on mixed convection of a lid-driven cavity which is filled by Al2O3/water nanofluid have been investigated numerically. Two-dimensional elliptical governing equations have been solved using the finite volume technique to investigate the hydrodynamics and thermal behaviors. The Nu number, streamline, and temperature distribution of the nanofluid flow are presented for two Ri. At Ri = 1 and 100, maximum cooling was achieved at α = 315. In some inclination angle ranges, average Nusselt number of the left wall is higher than the right one and vice versa. When a counterclockwise vortex appears at the near heated wall region and connects to the right-side wall, the Nu of the right-side wall increases. Also, when a clockwise vortex appears at the near heated wall and connects to the left one, the Nusselt number of the left-side wall increases. Average Nusselt number of the bottom wall (heated wall) decreases with increasing nanoparticle concentration, while the Nusselt number of the left and right walls (cooled walls) increases. However, in the cavity, natural convection could act against force convection and weaken its effect.