Advanced Chemical Laser Nozzle Concepts.

Abstract : The purpose of this program was to investigate experimentally the performance characteristics of high-pressure recovery, high-performance, advanced nozzle concepts for supersonic chemical lasers. Tests were conducted at small-scale (1 by 3 inches) sizes using scanning mirrors and a high-spatial-resolution IR spectrometer to examine performance. A small water-cooled pitot probe was used to scan the flowfield at the cavity exit to measure potential pressure recovery. A large-scale version of one of the nozzle configurations was designed and fabricated during this program and tested at the Mesa facility by the Aerospace Corporation. The Mesa results provided size scaling data for projecting Laser Engineering Test Facilities (LETF) results to larger sizes. Screening tests were performed on an advanced nozzle concept which provides increased mixing rates, larger throat dimensions, and decreased fabrication time and cost. The results of the screening tests indicated that the nozzles performed as predicted.