A CW HF Laser with Supersonic Premixing and Stationary Shock Initiation
Abstract
Formation of HF by the chain reaction is initiated by the simultaneous reaction NO + F2 yields NOF + F. A detonable mixture of the reactants, H2, F2, and NO in argon or helium diluent, is achieved by secondary injection of H2 and NO along the trailing edges of a two-dimensional nozzle array into a cold supersonic stream of premixed F2 plus diluent. Mixing of the secondary injectants is achieved without significant chemical reactions in slightly divergent supersonic mixing section. The resultant detonable mixture is directed into a chamber as a slightly underexpanded free jet. This free jet is interrupted shortly downstream of its exit plane by a nearly normal shock wave. The shock is held in a stationary manner by a shock holder which accepts only a portion ( approximately 70%) of the total jet flow. An adjustable sonic throat, within the shock holder, controls the accepted fraction. Laser mirrors in a fixed stable-cavity configuration constitute two walls of the shock holder. Maximum laser cavity intensity, sampled through several small holes in one mirror, presently appears to be in excess of 51 w/sq cm, as deduced from measurements of power in excess of 117 mw incident on a PbSe detector. Laser power output in excess of 20w, in a closed cavity configuration, was determined from local mirror heating by thermocouple measurements. This work represents the first success in achieving a stationary shock in a detonable mixture in a configuration other than a free jet. Furthermore, it represents the first demonstration of CW laser operation across a stationary shock.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1977
- Accession Number
- ADA041779
Entities
People
- Charles E. Kolb
- James P. Moran
Organizations
- Aerodyne Research