Reaction and internal energy relaxation rates in viscous thermochemically non-equilibrium gas flows
- Department of Mathematics and Mechanics, Saint Petersburg State University, Universitetskiy pr., 28, Saint Petersburg 198504 (Russian Federation)
In the present paper, reaction and energy relaxation rates as well as the normal stress are studied for viscous gas flows with vibrational and chemical non-equilibrium. Using the modified Chapman-Enskog method, multi-temperature models based on the Treanor and Boltzmann vibrational distributions are developed for the general case taking into account all kinds of vibrational energy transitions, exchange reactions, dissociation, and recombination. Integral equations specifying the first-order corrections to the normal mean stress and reaction rates are derived, as well as approximate systems of linear equations for their numerical computation. Generalized thermodynamic driving forces associated with all non-equilibrium processes are introduced. It is shown that normal stresses and rates of non-equilibrium processes can be expressed in terms of the same driving forces; the symmetry of kinetic coefficients in these expressions is proven. The developed general model is applied to a particular case of a pure N{sub 2} viscous flow with slow VT relaxation. Normal stress and rates of vibrational relaxation are studied for various ratios of vibrational and translational temperatures. The cross effects between different vibrational transitions in viscous flows are evaluated, along with the influence of anharmonicity and flow compressibility on the first-order corrections to the relaxation rate. Limits of validity for the widely used Landau–Teller model of vibrational relaxation are indicated.
- OSTI ID:
- 22403210
- Journal Information:
- Physics of Fluids (1994), Journal Name: Physics of Fluids (1994) Journal Issue: 1 Vol. 27; ISSN 1070-6631; ISSN PHFLE6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
74 ATOMIC AND MOLECULAR PHYSICS
APPROXIMATIONS
BOLTZMANN STATISTICS
COMPRESSIBILITY
CORRECTIONS
DISSOCIATION
EXCHANGE INTERACTIONS
GAS FLOW
INTEGRAL EQUATIONS
REACTION KINETICS
RECOMBINATION
RELAXATION
STRESSES
THERMOCHEMICAL PROCESSES
THERMODYNAMICS
VISCOUS FLOW