In order to increase the mixing rate by stretching the interface between reactant streams, we have developed gas trip nozzles and new supersonic nozzle designs (called ramp nozzle and deflector nozzle). Unlike trip nozzles which use inert gas injection to stretch the reactant surface, the ramp or deflector nozzle is believed to cause a similar effect through its geometry without gas injection. In this paper we report results of experimental investigation of the gain in a deuterium fluoride combustion driven chemical-laser operating at high cavity pressure (P > 15 Torr). Comparison of the small signal gain profile, observed along the gas flow direction, indicates appreciable differences between trip, ramp and deflector nozzles. At cavity pressure of about 15 Torr a peak gain value of 7 %/cm has been measured with the trip nozzles, the gain being positive up to 30 mm from the nozzle exit plan. The gain caracteristics of the laser with the trip jet flow on are quite different from those when the trip jets are off (laminar mixing). In this latter case the gain is only 1.5 %/cm. With ramp and deflector nozzles, shorter gain regions extended over only 20 mm were observed.

Date Published: 1 February 1991
PDF: 5 pages
Proc. SPIE 1397, 8th Intl Symp on Gas Flow and Chemical Lasers, (1 February 1991); doi: 10.1117/12.25923

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