Numerical Simulation of Combined Natural Convection Surface Radiation for Large Temperature Gradients

A study was conducted to analyze the physical differences between numerical simulations obtained with both the Boussinesq and low-Mach-number (LMN) forms of the Navier?Stokes equations for natural convection flow coupled with surface radiation in simple geometries. The study investigated the combined effects of surface radiation and temperature-dependent viscosity and conductivity on the momentum and heat transfer in the enclosure, along with quantifying how the incompressible flow assumption differed from the compressible form when solving flows driven by gravity acting upon density variations resulting from local temperature gradients. The selected characterization parameters of the maximum convective and radiative Nusselt number, the average Nusselt number, and the normalized pressure reduction were calculated from these simulations.