The Application of Lagrange and Pidduck-Kent Gradient Models to Guns Using Low Molecular Weight Gases
Final rept. May 1990-Apr 1991
ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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Increasing interest in hypervelocity and the potential offered by electrothermal gun systems for the practical application of novel propellants have led to a search for energetic materials which, upon reaction, generate gaseous products with low average molecular weight. It has been suggested that, as a result of using low molecular weight gases, traditional interior ballistic gradient models are not applicable in simulations of the interior ballistic process. The assumptions underlying the classical interior ballistic gradient models are reviewed and their ranges of applicability are discussed. Comparisons of the results of lumped parameter interior ballistic simulations using the Lagrange and Pidduck-Kent pressure gradient models and a one-dimensional hydrodynamic model, over a range of charge to mass ratios, are presented. It is shown that the traditional gradient models are applicable in the simulation of a gun using a low molecular weight gas, and are thus applicable in simulations of the electrothermal gun, within the normal limits of validity of the gradient models... Interior ballistics, Electrothermal gun, Light gas guns, Lagrange gradient model, Pidduck-Kent gradient model.