Numerical Study of Coupled Heat and Mass Transfer in a Trapezoidal Cavity

In this paper, we present a numerical three-dimensional study of coupled heat and mass transfer by natural convection occurring in a trapezoidal cavity. Our objective is to evaluate numerically the thermal and hydrodynamic behaviour of this system. It is assumed that the cavity vertical walls are thermally isolated and impermeable, and we imposed on the lower surface a constant high temperature and concentration. The upper surface is supposed to be cooled at a constant temperature and has a zero concentration.Governing equations are solved by a finite-volume technique and provide the temperature, concentration and velocity fields in binary mixture air-water vapor system. The obtained results show that the flow configuration depends strongly on the α angle inclination of the upper wall. The influence of the cavity dimensions on heat and mass transfer rates is also examined. In particular, as the aspect ratio increases, multi-cellular flow patterns start to form.