Effect of Emissivity on the Heat and Mass Transfer of Humid Air in a Cavity Filled with Solid Obstacles

Abstract

The work reported here is a 2D numerical study on the buoyancy-driven low-speed turbulent flow of humid air inside a rectangular cavity partially filled with solid cylindrical objects for a Rayleigh number of 1.45 × 10⁹. Variations of Nusselt number, buoyancy flux, vapor mass fraction, and turbulence viscosity ratio are presented for various emissivity values of wall surfaces. It was observed that during the natural convection process, radiation effects are very significant and the air/water vapor combination results in a small increase in heat transfer as compared with the pure natural convection of dry air.