Simulation of concentration convection at different pressures and compositions of a three-component gas mixture

Abstract

This article discusses the mathematical and computer modeling of the influence of pressure and composition of a three-component gas mixture on concentration convection based on the solution of the Navier-Stokes equations system, the continuity equation and equations for the concentration of the mixture components. The process is investigated when heavy gas and light gas are in the upper part of the parallelepiped, and gas with intermediate density in the lower part. Numerical calculations were carried out for the systems 0.55Ar+0.45He-N₂, 0.66Ar+0.34He-N₂, 0.55CO₂+0.45He-N₂ on a uniform rectangular grid. The dynamics of changes in the concentrations of argon and carbon dioxide for these systems at various pressures were presented in the form of figures. The results of the numerical study were obtained using a 3D numerical algorithm implemented on the basis of the D3Q27 model Lattice Boltzmann equations method with Batnagar-Gross-Crook (BGK) approximation. The performed calculations show that complex mass transfer is possible, associated with the occurrence of convective disturbances in three-component gas mixtures at certain pressures and compositions. To test the numerical algorithm, the results obtained in this article were compared with the results obtained experimentally and showed good agreement.