Thermodynamic charts for nonequilibrium plasma flow in a supersonic nozzle

Presented in this article is a one-dimensional, nonequilibrium analysis for reacting flow in a supersonic nozzle, Thermodynamic charts of different entropy values were developed to take into account the effects of finite reaction rate during the transition from local chemical equilibrium (LChE) to frozen now. At a given entropy the LChE curve was calculated first. Frozen flow solutions starting at different points on the LChE curve were then computed and plotted on a constant-entropy plane, The first and second laws of thermodynamics were employed to determine the ranges of valid solutions on different constant-entropy planes. Variations of temperature, pressure, and chemical affinity along the nozzle were computed for argon plasma at 10 atm and 15,000 K discharged through a supersonic nozzle to 0.05 atm, Effects of entropy change on the region of valid plasma states that were bounded by LChE and frozen flow solutions were examined. Three-dimensional plots were made to assist in viewing the variations of plasma state and nozzle performance when irreversibility due to finite reaction rates was considered. It was found that the range of valid states for a reacting flow decreases as entropy increases. Consequently, only charts within a certain entropy range are needed for a given reservoir condition.