Investigation of Electrically Controlled Ammonium Nitrate – Epoxy Solid Propellant at High Pressures

Abstract

AbstractThe effect of electric voltage/power application on the burning rate of solid propellants composed of ammonium nitrate (AN) and epoxy at high pressures was investigated experimentally. Such an effect can yield an effective means for real‐time managing of the thrust of a solid rocket motor. A burning rate increase up to about 4 folds when increasing voltage application from 70 V to 200 V, was demonstrated. It was attributed to energy (heat) release due to an electric current passing through the conductive melt layer formed at the burning surface. The relative increase in burning rate due to electric effect was higher at the lower pressure range, diminishing for the higher‐pressure end because of the lower relative electric energy contribution. The common pressure dependence correlation of the burning rate could be applied only for limited ranges. However, because of the coupling between the pressure and specific electric power (power per unit surface area) effects, a more complex correlation which includes a variable pressure exponent, was revealed and applied successfully to fit the data over a range of specific electric power and pressure.