Soret and Dufour Effects on Free Convection Heat and Mass Transfer in a Doubly Stratified Darcy Porous Medium

摘要

Free convection heat and mass transfer from a vertical surface in a doubly stratified Darcy porous medium subject to Soret and Dufour effects is studied. The similarity solution is possible for the case of constant heat and mass flux conditions, when the thermal and solutal stratification of the medium are assumed to vary in the power function as x{sup}(1/3). The flow, temperature, and concentration fields are affected by the complex interactions among the diffusivity ratio Le, buoyancy ratio parameter N, Soret number S{sub}r, Dufour number D{sub}f, and the thermal and solutal stratification parameters ε{sub}1 and ε{sub}2, respectively. The results for the wall temperature and concentration obtained are presented for various values of the parameters Le, N, ε{sub}1, ε{sub}2, S{sub}r, and D{sub}f. It is noted that large differences between the values of S{sub}r and D{sub}f, and of ε{sub}1 and ε{sub}2, lead to changes in the sign of the temperature and concentration fields.