Modeling HF Gain Generator F-Atom Flows

摘要

Control volume analysis and one-dimensional reacting gasdynamics have been combined with a unique thermal-mechanical model of a combustor vessel to estimate production of fluorine atoms at the nozzle exit plane. Upon reaction with hydrogen, H2, these F-atoms are a key species in the efficient production of internally energetic hydrogen fluoride (HF) molecules, which is the lasant material for an HF chemical laser. Thus, a quantitative estimate of F-Atom density and more specifically the degree of fluorine (F2) dissociation, alpha, is an essential parameter for the accurate prediction of laser performance. This parameter, as a function of time, has been difficult to experimentally measure or to analyze in such lasers. The method has been applied to the only cylindrical HF chemical laser in operation. Test conditions for the must recent tests of the Alpha Laser are analyzed. It is found for the baseline operating point that alpha reaches a plateau exceeding 0.9 after a sufficiently long operating time. Necessarily for the expediency of rapid calculations, such a model lacks the temporal and spatial fine details of the heat transfer processes, gasdynamics, and boundaries. Therefore, such a model is valuable for insight, but must be used with care for detailed design.