Visualization and Measurement of the Deflagration of JA2 Bonded to Various Metal Foils

Abstract : A series of experiments was conducted to better understand the mechanisms underlying the deflagration of nitrate ester-based propellants embedded with thermally conductive components. JA2 propellant was employed for the experiments. Strands were bonded on one side with an aluminum or copper foil, and their deflagration was videographically recorded. Foil thicknesses ranged from 1 to 3 mil. The data yielded measured values for 1) the JA2 stocks normal, linear-burning rate, 2) test-article burning rates relative to an axis parallel to their side wall, and 3) the angle between the burning surface and the side wall. The condensed-phase to gas-phase mass conversion rates for foil-bounded sections were up to 4 times higher than those for foil-less sections. The increases appear to be almost entirely due to increases in the area of the burning surface rather than an increase in the normal, linear-burning rate. It was also found that the pressure dependence of the gas-generation rates for foil-bounded sections was slightly less than that of foil-less sections. Because the test articles had a relatively simple geometry, the results should provide a good basis with which to validate computational fluid-dynamics models for simulating the deflagration of wire-embedded propellants.