Иерархия времен релаксации и модельные кинетические уравнения

Gas mixtures with internal degrees of freedom and chemical reactions are considered. It is necessary to take into account molecular collisions with the change their internal energy of different kinds and chemical composition. It is known that molecular collisions of different kind happen with various frequency. It follows the hierarchy of relaxation times and the establishment of weakly non-equilibrium on some and strongly non-equilibrium on other degrees of freedom molecular distributions in gas flows. After analogy of the Krook equation, the model kinetic equations are proposed for the investigation of such flows. The correctness of H-theorem is proved. Closed systems of the equations for macroscopic parameters (extensive and intensive) are produced in different approaches of the Chapman-Enskog method. The preferences of transition from extensive to conjugate intensive parameters are discussed.