Turbulent Natural Convection in an Enclosure With a Triangular Roof with Different Inclination Angles

Abstract

The turbulent natural convection in a square enclosure with triangular roof is studied employing the standard k−ε model. The flow and thermal characteristics are presented in the form of streamline, isotherm contours, velocity vector, turbulent kinetic energy and dissipation of turbulent energy. Local and average values of Nusselt number and heat flux are also presented for top and side walls for Rayleigh numbers ranging between 5 ×109 and 1×1011. The finite volume method based SIMPLE algorithm is utilised for understanding the flow and thermal behavior arising due to buoyancy. The convective flux is discretised using the power law upwind scheme while the diffusive term is discretised using central difference scheme. The effect of roof inclination is also studied by varying the height. It has been observed that the cooling capacity, represented by the heat flux through cold vertical wall decreases with increase in height H, but after a certain value of H, heat flux is almost constant.