INVESTIGATION OF CHEMICAL AFFINITY FOR REACTING FLOWS OF NONLOCAL THERMAL-EQUILIBRIUM GASES

Use of chemical affinity for analyzing reacting flows of gases not in local thermal equilibrium (LThE) is investigated. The affinity is used as a parameter to define the degree of reaction extent in reacting flows. The relation between the reaction rate and the affinity for a multitemperature ideal gas mixture is also investigated and discussed. Each gas species in the mixture is assumed to have a Maxwellian velocity distribution, and the particle distribution for each internal energy mode is characterized by a Boltzmann or an equivalent population temperature. It is found that the relation between the reaction rate and the affinity for non-LThE gases fan be reduced to that for LThE gases if modified stoichiometric coefficients and modified mole fractions are employed in the exponential function relationship, Results of the present investigation are applied to the ionization reaction of argon with nonequilibrium translational and electronic excitation temperatures. Equations and charts for computing the composition and thermodynamic properties of singly ionized argon plasma are presented for various non-LThE temperatures and different affinity values. An example of argon ionization reaction is given to illustrate the use of these charts.