J. Phys. Colloques
Volume 41, Numéro C9, Novembre 1980Third International Symposium on Gas-Flow and Chemical Lasers
|Page(s)||C9-335 - C9-341|
J. Phys. Colloques 41 (1980) C9-335-C9-341
EXPERIMENTAL INVESTIGATIONS OF GASDYNAMIC N2/CO2 MIXING LASERSH. Hügel1, W. Schall2 et P. Hoffmann1
1 Institut für Technische Physik, DFVLR, D-7000 Stuttgart 80, Fed. Rep. Germany.
2 Instiut für Technische Physik, DFVLR, D-7000 Stuttgart 80, Fed. Rep. Germany.
N2/CO2 mixing lasers with thermal excitation of the N2 in arc-heaters and with screen nozzles for the expansion and mixing process are investigated. Results obtained with two devices having different cross-sections of the laser channel are compared. For equal operating conditions the small signal gain is well correlated by a normalized distance downstream of the nozzle exit plane. The distribution of gain along the flow direction is mainly determined by the stagnation temperature, the ratio of N2/CO2 and the presence of He. Values of small signal gain up to 3 % cm-1 are achieved. The effect of replacing N2 by CO is studied in detail. The observed reduction of laser performance depends on the ratio of N2/CO/CO2 but is almost independent of stagnation temperature. In addition, preliminary experiments aiming at the substitution of N2 by air yield a specific laser energy of 5 J/g.