Spectroscopic investigation of interaction between propane jets injected into a supersonic flow of air under conditions of development of a nonequilibrium discharge in one of the jets

Emission spectroscopy is used to investigate the flow arising under conditions of injection of propane jets into a supersonic flow of air in the longitudinal direction; these jets are spaced apart in the initial zone of injection, and a nonequilibrium discharge is developed in one of the jets. Experiments are performed at Mach number $\text{M} = 2$, static pressure of $3.47 \times 10^4$ Pa, and discharge current of $1$ A. Data are obtained on the composition and space distribution of radiating products arising in the process of conversion of fuel-and-air mixture in the resultant combined flow. In particular, data are given on the distribution of intensity of radiation of $\text{C}_2$, $\text{CN}$, and $\text{CH}$ radicals, as well as of atomic hydrogen and oxygen. The investigation results enable one to give a positive answer to the previously uninvestigated question of the possibility of ignition of a fuel-and-air mixture in supersonic flow, which propagates outside of the zone of reactions, supported by the nonequilibrium discharge. It is found that the redistribution of fuel between the main flow in which no discharge is present and an auxiliary channel in which the discharge is generated may result in a higher efficiency of the processes occurring in the main flow. The employed methods make it possible to determine the geometry of arising flow in the presence of plasma-chemical reactions.