Flowfield experiments on a tripped DF chemical laser

Three diagnostic techniques were used to obtain qualitative data on the cavity reactant mixing rates and quantitative small-signal gain data; which could be used to verify flowfields and kinetics models in laser performance codes for the case of a DF chemical laser cavity flowfield operating in the laminar and augmented (tripped) mixing modes. The techniques used were: (1) infrared photography of DF and HF spontaneous emission; (2) high-resolution mapping of spontaneous DF cavity emission with an infrared scanner; and (3) DF small signal gain measurements. It was found that of the two types of IR photographs made, tests using H2 seeding of the laser stream yielded far superior results to those recording DF emission in order to detail reactant mixing characteristics. Results from the more quantitative IR scanner tests verified that the HF emission boundaries recorded photographically correspond to reactant mixing boundaries.