Transverse electric discharges in supersonic air flows: simulation of gasdynamic effects in the discharge channel

Abstract

A model of heat source is validated for the description of the gasdynamic aspects of interaction between a discharge channel and supersonic flow, which are defined by the heating of gas. The model is based on the characteristic features of a discharge in supersonic flow, which are observed in the case of nonequilibrium plasma whose conductivity is defined by the degree of ionization, namely, rapid heating of air in the electrode regions and relatively low values of reduced electric field in extended discharge channels behind these regions. The rapid heating mechanism leads to a redistribution of the power of Joule heat to the front part of the channel, which enables one to simulate a discharge as a heat source with a short ellipsoidal zone of heat input. This approach enables one to attain agreement between the calculated axial distributions of temperature and velocity of flow and the experimental data. It is demonstrated that unsteady-state conditions of energy input make it possible to experimentally simulate gasdynamic effects of interaction between stationary heat sources and supersonic flow when single pulses are used and in the case of pulse-periodic mode.

Transverse electric discharges in supersonic air flows: Simulation of the effects influencing the heating of gas in discharge channel

“…The obtained results demonstrated that the apparently natural model of extended cylindrical source, as well as the frequently employed model of spherical source, is hardly suitable for describing the interaction between the discharge channel and flow. From the gasdynamic standpoint, the discharge "shines but not warms": the extended parts of discharge spend electric energy but do not contribute to the heating of gas [8]. Agreement with experiment in the distribution of gas temperature and flow velocity is reached for sources whose extent is several times longer than their diameter.…”

“…It is associated with the mechanism of "rapid heating of gas", i.e., the heating during periods of time much shorter than the time of vibrational relaxation [6,7]. This mechanism was used in [8] to construct a simple model which treats the discharge as the zone of energy release and enables one to describe gasdynamic effects due to the heating of gas in a supersonic flow. In so doing, primary attention was given to analysis of distribution of energy input along the flow.…”

“…However, Georgievskii et al [8] made a number of simplifications. They ignored the effect of the jet under conditions of which the discharge was burning and the measurements were performed [3]; they further ignored the hydrodynamic interaction between discharge channels parallel to one another.…”

“…This study is a continuation of [8]. It is our objective to analyze the importance of the assumptions made in [8], estimate the errors involved, and make detailed comparison with experiment.…”

“…It is our objective to analyze the importance of the assumptions made in [8], estimate the errors involved, and make detailed comparison with experiment. In so doing, we will keep some simplifications of [8], namely, ignore the effect of the electrodes on the flow and employ the value of energy input used directly to heat the gas.…”