Numerical Investigation on Natural Convection in Inclined Channels Partially Filled With Asymmetrically Heated Metal Foam

Abstract

A numerical study on natural convection in an inclined channel partially filled with open metal foam is investigated in two-dimensional laminar and incompressible and steady-state condition. The upper wall is heated at uniform heat flux, and the lower wall is adiabatic. The governing equations for the metal foam are written assuming the Brinkman–Forchheimer-extended Darcy model and the local thermal equilibrium (LTE) hypothesis. The inclination angle with respect to the horizontal direction ranges between 0 deg and 90 deg. The metal foam structure is homogenous and isotropic and the thermophysical properties are assumed constant with the temperature. The main aim of the present study is to analyze the effect of inclination angle, pore density, and porosity to improve the knowledge on the thermal behaviors of natural convection in partially filled channel with metal foam. Moreover, this study aims to evaluate the possible improvement with respect to the clean inclined channel. Results are presented in terms of velocity and temperature fields, and both temperature and velocity profiles at different significant sections are shown, to obtain a description of the natural convection inside the inclined channel. Finally, average Nusselt number values are evaluated. The presence of metal foam affects the fluid flow in the channel with different motion behaviors. The heat transfer rate increases with the increase in inclination angle, and the average Nusselt number shows different trends for lower and higher Rayleigh numbers, Ra. A significant enhancement is detected for the higher Ra and it depends on the porosity and pore density.