RESUMO

In this paper, the effects of the variation of the out of phase and the inclination angles on natural convection heat transfer of air in a sinusoidal corrugated enclosure are investigated numerically. The present study is based on a configuration where the two vertical sinusoidal walls and the horizontal bottom wall are maintained at constant low temperature, whereas the flat upper wall temperature distribution of the enclosure is assumed to vary with a sinusoidal function. The governing equations of continuity, momentum, and energy are solved computationally using finite-volume techniques. The solution procedure is based on the SIMPLE algorithm and a nonorthogonal, nonuniform collocated grid system. The effects of various orientations on the heat transport process inside the sinusoidal corrugated enclosure are studied in detail. The computational results are presented in terms of isothermal lines and streamlines for different governing parameters. The values of the governing parameters are the inclination angle of the enclosure γ (0°−90° ), out of phase angle Ø (0°−180°), Rayleigh number (10³−10⁶), and Prandtl number (0.71). The main results of this investigation illustrate that the effect of γ on the streamlines and the isothermal lines is very important for all values of Ra and Nu. The centers of vortices will move upward into the upper surface with increasing Ra. The local Nusselt number along the cold left wavy sidewall is increased with increasing Rayleigh numbers at γ = 0°. For γ > 0° ,the average Nusselt number is decreased with increasing Ra along the left wavy sidewall, while the average Nusselt number is increased with increase of Ra along the right wavy sidewall. At γ = 0°, two vortices appear that control the flow inside the enclosure for all values of Ra, Nu, and the out of phase angle, while at γ = 90°, one vortex appears that controls the flow inside the enclosure for all values of Ra, Nu, and the out of phase angle.