Numerical study of natural convection in an inclined rectangular cavity with partially heated sidewalls including radiation effect.

Abstract

Natural convection heat transfer in an inclined rectangular cavity with radiation effect is crucial for various real-world applications ranging from energy efficiency and thermal comfort to process optimization and environmental sustainability. The effectiveness of natural convection heat transfer in an inclined rectangular enclosure is investigated in this study in response to variations of aspect ratios, inclination angles and due to radiation. The investigation is done in three cases. In all cases, the bottom wall and lower half of the right sidewall are kept at a high temperature, the upper wall and the upper half of the left sidewall are kept at a cold temperature, the lower half of the left sidewall is kept at a linear temperature. In first case, the upper half of the right sidewall is kept adiabatic. In second case, the boundary conditions are same as in the first case but in this case, the inclination is added. In third case, the upper half of the right sidewall is kept radiative where the emissivity is 0.95 and the variations of the inclination angles are same as in the second case. The non-dimensional governing equations are solved using finite element techniques based on Galerkin Weighted residuals. The effect of aspect ratios, inclination angles, and radiation on fluid flow for various Rayleigh numbers are discussed in this study. The investigation is performed for aspect ratios 0.5, 1, and 2, for inclination angles of 〖30〗^0,〖45〗^0,and 〖60〗^0, for Rayleigh numbers of 〖10〗^3,〖10〗^4,〖10〗^5,and 〖10〗^6 while Prandtl number is kept fixed at 0.71 and aspect ratio(AR) is the ratio of height(H) and length(L) of the cavity. In addition, various features such as streamlines, isotherms, velocity profiles, temperature profiles, and heat transfer rate in terms of the average Nusselt number (Nu_avg) are shown for the experimental parameters. The present result showed that the rate of heat transfer improves as the Rayleigh number increases. The results also showed that the heat transmission rate rises when the inclination angle decreases to 〖30〗^0, and the aspect ratio decreases to 0.5. Again, due to radiation, the heat transmission rate reduces. The findings of this study are very consistent with those of previous research.