Thermosolutal convection flow and the associated heat and mass transfer process in a square enclosure

Thermosolutal convection flow and its effect on the heat and the mass transfer in a square enclosure is studied experimentally. Both thermal and solute diffusion are induced from the sides, and natural convection is initiated by the combined thermal and solutal buoyancies which either augment with or oppose to each other. The solute diffusion is initiated in an electrochemical system that uses copper sulphate-sulphuric acid solution as an electrolyte. Depending on the magnitude of buoyancy ratio, three different kinds of flow regimes and structures can occur which lead to different distributions of concentration in the enclosure. The solutal boundary layer flow which can intrude and accumulate along the horizontal wall leads to the formation and growth of layered flow structure. The nearly stagnant layer occurred can reduce the heat transfer rate. The Nusselt numbers at different flow regimes are measured and correlated in terms of relevant nondimensional parameters. This suggests the correlation of Sherwood number in different ranges of buoyancy ratio. The visualization of flow structure and measurements of both heat and mass transfer allow a better understanding of the complicated system.