Conjugate Radiation and Convection Heat Transfer Analysis in Solar Cooker Cavity Using a Computational Approach

Abstract

The heat loss caused by radiation and persistently laminar natural convection in a solar cooker cavity that has a rectangular cavity or a trapezoidal cavity are computationally explored in this paper. The hot bottom and the adiabatic side wall are both taken into account. Two possibilities are considered for the top wall: first, a cold wall, and, second, losses from wind-induced convection and radiation. The parameters of heat loss in various depth cavities have been investigated along with a variety of external heat transfer coefficient values above the glass surface were simulated. The emissivity of the bottom surface, the absolute temperature ratio, on heat loss from the considered geometries, are also calculated. Analysis of the cavity’s flow pattern and isotherms at different depths has been conducted, and it is discovered that the total rate of heat transfer from the top wall increases as the bottom wall’s emissivity, the absolute temperature ratio, the Rayleigh number, and the external Nusselt number all increase. While radiation heat transfer increases monotonically, convective heat transfer rates shift slightly as these values rise at different emissivities of the bottom, and the opposite occurs when Ra increases at the same emissivity. Furthermore, it has been discovered that as the aspect ratio of the cavity increases, the overall Nusselt number decreases. A trapezoidal cavity has a faster rate of heat transfer than a rectangular cavity for the same parameters. Generic empirical correlations were developed for the total average Nusselt number concerning all influencing parameters.