Fluid processes in supersonic diffusion lasers

The pressure distribution was measured downstream of two different screen nozzles in a combination shock-Ludwieg tube facility that mixes pure A or a 5% F2/A oxidizer with H2 fuel. A quasi-one-dimensional coupled fluid-chemistry model is developed which is used to systematically isolate prominent fluid processes. Nozzle geometries, nonideal expansions, overall and relative entrainments, base entrainment, and base pressure are explored and reference conditions selected. With these choices the model was found to be in general agreement with the experimental results. It was then used to predict HF laser performance for a particular set of conditions. Significant fluid process sensitivity is predicted.