Convection of a Binary Mixture with Thermal Diffusion Coefficient That Depends on Temperature

Abstract

In this paper we present the results of numerical simulation of nonlinear regimes of a NaCl aqueous solution in a square cavity with rigid and impermeable for substance boundaries. The vertical boundaries are thermally insulated, there are different constant temperatures on horizontal ones, it corresponds to the heat from below. The calculations are carried out within the non-stationary approach, with using of Boussinesq approximation and taking into account the polynomial dependence of the thermal diffusion coefficient on temperature. According to experimental data, the sign of thermal diffusion coefficient of the mixture under study changes at a temperature 285.4 K. In this work we consider a temperature range such that the sign of the thermal diffusion coefficient changes inside the simulated region. Other transport coefficients factors are considered as constant. The calculations were carried out for the cases of Earth and reduced gravity. A comparison is made with the case of the thermal diffusion coefficient constant value, which is negative at the considered average temperature.