Experimental and analytical study of CO2/N2 mixing gasdynamic laser

The nonequilibrium effects of the CO2 flow and the characteristics of a CO2/N2 mixing GDL are studied, using two synchronized nondiaphragm shock tubes over a wide range of stagnation conditions. A numerical model is presented assuming instantaneous mixing, and a three-mode model, describing the vibrational relaxation in CO2/N2/He is discussed. Results indicate that the synchronization of the two shock tubes was achieved with a mismatch of less than 400 microsec by the electrical control of nondiaphragm driving mechanisms with free pistons. The best lasing performance was recorded in the case of the downstream mixing of N2 with expanded CO2.