Calculation of chemical- and vibrational-nonequilibrium flow of a multicomponent gas through a nozzle

Vasil'ev, V. M.; Kulikov, S. V.; Skrebkov, O. V.

doi:10.1007/bf00851380

Cited by 2 publications

(2 citation statements)

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“…Equations of chemical and vibrational kinetics for general case of reacting multi-component gas mixture in frames of macroscopic (or hydrodynamic) description, i.e., in the form of equations for the concentrations of mixture components, n i , and average energies of vibrational degrees of freedom (modes), ε k , were first published in [22] (see also [23]). These equations were used for calculations of chemical and vibrational nonequilibrium multi-component gas flow through a nozzle while studying the combustion-driven CO 2 -gas-dynamic laser working media.…”

Section: Kinetic Equationsmentioning

confidence: 99%

“…In deriving these equations from the equations of balance of the vibrational level populations (or Master equations) [24], the following simplifying assumptions were made: 1) chemical reactions do not disturb the Maxwell distribution; 2) rotational degrees of freedom are in equilibrium with the translational ones; 3) each type of molecular vibrations (mode) is modeled by a harmonic oscillator with vibrational temperature T k as a measure of the average energy of that or another mode (such as the kth). Following [22] [23] in general (see also [16] [24]), we have the equations for the molar component concentrations per unit mass, n i , and the average numbers of vibrational quanta of kth mode per one molecule, ε k , as the time functions at given gas temperature, T, and pressure, p. (In terms of nonequilibrium statistical mechanics, these equations are the corresponding moments of the Master equations. )…”

Section: Kinetic Equationsmentioning

confidence: 99%

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Vibrational Nonequilibrium in the Hydrogen-Oxygen Reaction at Different Temperatures

Skrebkov¹

2014

JMP

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A theoretical model of chemical and vibrational kinetics of hydrogen oxidation is suggested based on the consistent account for the vibrational nonequilibrium of HO2 radical which forms in result of bimolecular recombination H + O2 = HO2 in the vibrationally excited state. The chain branching H + O2 = O + OH and inhibiting H + O2 + M = HO2 + M formal reactions are considered (in the terms of elementary processes) as a general multi-channel process of forming, intramolecular energy redistribution between modes, relaxation, and monomolecular decay of the comparatively long-lived vibrationally excited HO2 radical which is capable to react and exchange of energy with another components of the mixture. The model takes into account the vibrational nonequilibrium for the starting (primary) H2 and O2 molecules, as well as the most important molecular intermediates HO2, OH, O2(1 ∆), and the main reaction product H2O. The calculated results are compared with the shock tube experimental data for strongly diluted H2-O2 mixtures at 1000 < T < 2500 K, 0.5 < p < 4 atm. It is demonstrated that this approach is promising from the standpoint of reconciling the predictions of the theoretical model with experimental data obtained by different authors for various compositions and conditions using different methods. It is shown that the hydrogen-oxygen reaction proceeds in absence of vibrational equilibrium, and the vibrationally excited HO2 radical acts as a key intermediate in the principally important chain branching process. For T < 1500 K, the nature of hydrogen-oxygen reaction is especially nonequilibrium, and the vibrational nonequilibrium of HO2 radical is the essence of this process.

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Section: Kinetic Equationsmentioning

confidence: 99%