Algorithm for studying inversion in gas dynamic systems

T. E. Horton

doi:10.1117/12.144657

4 May 1993 Algorithm for studying inversion in gas dynamic systems

T. E. Horton

Proceedings Volume 1810, 9th International Symposium on Gas Flow and Chemical Lasers; (1993) https://doi.org/10.1117/12.144657
Event: Ninth International Symposium on Gas Flow and Chemical Lasers, 1992, Heraklion, Greece

Abstract

Solutions of the binary master equations for the state populations in an expanding gas are facilitated by the use of a flow similarity variable. This similarity variable accounts for the density and velocity variation associated with a gas dynamic expansion and can be expressed as a function of the local Mach number, the stagnation conditions, and a nozzle geometry parameter. With the similarity variable, the master equations are transformed into a form which is independent of the nozzle shape and similar to those for a non-flow system. This simplification facilitates both numerical solutions and closed form approximations for populations in nozzle flow. With solutions in terms of the similarity variable the design conditions leading to a population inversion can be presented as a simple algorithm. An illustration is presented for a wedge nozzle expansion. The conditions for inversion are determined by the expansion Mach number at a stagnation pressure. With the algorithm these conditions for a range of nozzle sizes are presented as an inversion criteria curve.

Citation Download Citation

T. E. Horton "Algorithm for studying inversion in gas dynamic systems", Proc. SPIE 1810, 9th International Symposium on Gas Flow and Chemical Lasers, (4 May 1993); https://doi.org/10.1117/12.144657

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