Nonequilibrium transport processes in problems on the nonuniform relaxation

The Boltzmann equation for mixtures of simple gases and also the model kinetic equation are solved for simulation of nonequilibrium processes at a scale of a mean free path in spatially nonuniform relaxation structures. The mixture of gases is considered because for a more complex medium it is possible to obtain a more complex nonequilibrium structure in this open system. Nonuniform steady relaxation processes for 1D and 2D cases are studied. The important relations observed earlier for a one-component gas are revealed. It is shown that transport in the relaxation zone is realized in a nonclassical manner. In particular, the heat flux of the mixture has the same direction as the gradient of the temperature of the mixture. The nonequilibrium convective heating or cooling of the region downflow depending on if the heat flux on the boundary is positive or negative is observed. It is also shown that the sign of the velocity gradient can be the same as the sign of the appropriate component of the nonequilibrium viscous stress tensor.