Extension of a Model of Liquid Injection in a Regenerative Liquid Propellant Gun Based Upon Comparison with Experimental Results
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Experimental data currently collected for the regenerative liquid propellant gun RLPG in the injection region include liquid and chamber pressures and piston position. Utilizing this data, it has been possible to extrapolate liquid velocity and values for the discharge coefficient. However, models of the RLPG currently in use have required the discharge coefficient to be an input with liquid velocity determined based on steady Bernoulli flow. In an effort to eliminate the discharge coefficient as an input, the authors have developed a formulation, presented in earlier reports, which couples the motion of the regenerative piston and velocity of the injected liquid which allows a prediction of the discharge coefficient. The objective of this paper is to determine the utility of the model in predicting direct and indirect experimental measurements in the RLPG. In the paper two sets of experimental data are examined, both 30-mm test fixtures differing primarily in the use of resistive forces on the piston and transducer block. The utility of the injection model to predict the experimentally measured motion of the regenerative piston and the derived values of the discharge coefficient is assessed. In general, the model is a good description of the liquid injection process in a regenerative liquid propellant gun. Keywords Interior ballistics.