Solutal convection and mass transfer in inclined enclosures

Both experimental and numerical work are performed to study the solutal convection flow and transport process in the enclosures that can be inclined at different angles. The enclosure is filled with an aqueous solution containing CuSO₄ + H₂SO₄, where the flow structure is visualized by both a particle tracer and shadowgraph. With a nonintrusive optical method the concentration fluctuations at desired locations are measured. The mass transfer Sherwood numbers across the enclosure at various inclinations are also measured and the results are correlated in terms of relevant nondimensional parameters. In the experiments, the Rayleigh number ranges from 1.126 × 10⁸ to 1.157 × 10¹¹, the Schmidt numbers from 2500 to 3989, the angles of inclination from 30 to 150 deg, and the aspect ratios of the enclosure from 0.25 to 1. The SIMPLE algorithm developed by Patankar is employed to calculate the solutal convection, and the results are compared with the data. It was found that both the inclination and the aspect ratio of the enclosure have a significant effect on the flow structure and mass transfer. For a large angle of inclination, the accumulation of solutal boundary-layer flow leads to stratification of the core and reduction of the mass transfer. For a small inclination, generation and protrusion of solutal plumes leads to oscillation of concentration and enhancement of mass transfer.