Influence of volumetric radiation properties on natural-convection in the low mach number approximation

Abstract

The study aims to investigate the dynamics of fluid-flow and thermal energy exchange within a 2-D differentially heated cavity using the low Mach number approximation. Specifically, it seeks to investigate the occurrences related to natural-convection and thermal radiation in a medium that exhibits absorption, emission, and scattering properties and exposed to a significant temperature difference. This methodology is applied within the framework of the low Mach number model of the Navier-Stokes equation. The interaction of momentum, energy, and radiation transfer equations within the cavity is addressed through an iterative approach that combines discrete-ordinates and finite volume methods enhanced by the SIMPLER algorithm. The obtained findings show that the low Mach number model overestimates radiative transfer, with higher radiative power in the absorbing-emitting case. Transparent media (? = 5) result in the highest heat transfer, while lower opacity favors the absorbing-diffusing medium. Flow intensity increases with albedo, and isotherms deform due to strong fluid dynamics. At high opacity, heat transfer is greater in transparent media, with lower velocities in more diffusing media.