A study of populations inversion formation in a chemically pumped mixing shock driven CO2?GDLhas been conducted. ColdN2O injection was made in parallels into a hot flow with a chemical composition 25%CO + 25%He + 50%Ar by means of a central-body-type injector. The experiments were carried out with the coordinates of the in jeotion point 5 mm, 4 mm, 3 mm, 2 mm before critical section of a nozzle and 0.4 mm behind critical section. Diagnostics of the supersonio flow was performed by means of a gain for 10.6 ?m in CO2-laser transition, intensity of IR emission of C02 in a 4.3 ?n band and intensity of visible chemiluminescence CO + O ? CO2 + hv recordings. Prom the measured values of the gain and intensity of IR emission vibrational temperatures of the laser levels were determined. The largest values of the gain up to 0.7 m-1 were obtained when the injection was in a 3 mm before critical section. The gain was recorded in the experiments with the injection in a 0.4 mm behind critical section. Chemical reactions occurred in each experiment in which stagnation temperature behind reflected shockwave exceed 1700 K. Vibrational temperature of the upper laser level in the experiments with reacting mixture was f ound to be considerably exceeding that in the experiments with inert mixture with a composition conformed to a composition of reacting mixture after completion of chemical conversions. The exceeding monotonously increased from 500 K to 900 K when the injection coordinate changed from 5 mm before to 0.4 mm behind critical section. Analogous exceeding of the lower laser level temperature reached 300 K. A strong chemiluminiscence was detected in the experiments with reacting mixture. Thus , quasy—stationary chemical pumping of CO2 vibrat ions by reactions o N2O with CO occurred in the nozzle o GDL was firstly observed.

Date Published: 1 February 1991
PDF: 9 pages
Proc. SPIE 1397, 8th Intl Symp on Gas Flow and Chemical Lasers, (1 February 1991); doi: 10.1117/12.26003

Published in SPIE Proceedings Vol. 1397:
8th Intl Symp on Gas Flow and Chemical Lasers
Concepcion Maroto Domingo; Jose M. Orza, Editor(s)