Modeling CW DF and HF Laser Performance at Low Cavity Pressures and Diluent Conditions.

摘要

A laser performance model originally developed for high cavity pressure and diluent c.w. lasers is extended to apply to a significantly lower pressure and diluent operating regime. The different class of laser nozzle geometries used in low diluent applications are described and a method for theoretically modeling the internal flow area expansion which occurs in these designs is presented. Experimental data (closed cavity power, chemiluminescence, zero power gain) for helium diluent hydrogen fluoride and nitrogen diluent deuterium fluoride chemical lasers is used to assess the accuracy of the model. Agreement between theory and data is good for both the axisymmetric and two dimensional nozzle geometries examined. Test conditions where theory and data do not agree are shown to be in part related to the influence of shroud geometry and vacuum duct pressure on the flowfield.