Abstract
The stability of mechanical equilibrium in the ternary gaseous mixtures at different pressures was investigated by two flasks method. Visual study of the process in isothermal ternary gaseous and liquid mixtures allowed detecting structural formations that significantly distort the steady diffusion process. Theoretically was studied the stability of isothermal ternary gaseous mixture in a plane vertical channel at boundary conditions, assuming the disappearance of speed and perturbation of the concentrations of components at the vertical planes, restricting the layer of the gaseous mixture. In the terms of diffusion Rayleigh numbers were drawn the maps of stability of ternary gaseous mixtures. The results of the linear analysis on stability are well agreed with the experimental data for the considered gaseous mixtures.