Numerical study of the natural convection flow resulting from the combined buoyancy effects of thermal and mass diffusion in a cavity with differentially heated side walls

摘要

This work is part of general study dealing with the improvement of the distillation rate in solar distillation systems.We are interested in the laminar flow which arises in fluids due to the interaction of the gravity force and density differences caused by the simultaneous diffusion of thermal energy and of chemical species.Species concentration levels are assumed small,as it is typical for many processes in water and in atmospheric air.This study states the problem in a Cartesian coordinates system,involves the use of a Control-Volume based Finite Element Method (CVFEM) and solves the full vorticity transport equation together with the stream function,concentration and energy equations.The predicted stream function patterns,mass,temperature and velocity profiles as well as the mean Sherwood and Nusselt numbers are presented and discussed for different combination of aspect ratios,Rayleigh numbers and buoyancy effects.