No abstract

An experimental investigation of heat transfer carried out for a semiannular enclosure. Inner and outer walls of the enclosure were kept at different but constant temperatures. The semiannular enclosure was filled with a CuSO4 - H2SO4 - H2O solution. An electrochemical method has been used for the mass transfer. The purpose of this study is to investigate flows resulting from buoyancy due to a combination of both temperature and concentration gradients in the enclosure. The flow structure in the enclosure was visualized by the shadowgraph technique. Flow visualization photograph showed interesting multi-cell flow structures in the enclosure for the cooperating and opposing thermal and solutal buoyancy. An optical technique is based on the idea that the intensity of the light beam absorbed by the copper sulphate solution is proportional to the solution concentration when the light beam passes through the solution. For each flow regime the mass transfer coefficient across the enclosure was also measured. The ranges of the dimensionless parameters studied in the experimental were Ar = 0.23, k = 2.5, Sc = 1700∼2300, Pr = 6.5 ∼ 7.3, Grt = 104 ∼ 106, N = −15.44 ∼ 6.16, θ = 45°∼90°.