Electrical ignition of HAN-based liquid propellants

Progress achieved in the study of the electrical ignition of the hydroxylammonium nitrate (HAN) based liquid gun propellant LGP 1846 is described. The goal of the work is to develop an ingiter system suitable for regenerative liquid propellant guns. Several ingniter configurations, designed by the Ballistic Research Laboratory and the Fraunhofer-Institut EMI-AFB, have been tested. Voltage and current as well as the pressure histories were recorded. Calculations of electrostatic field distributions discussed here were obtained by a finite element code implemented at Dynamit Nobel. The theoretical analysis yielded alternative electrode designs for future testing. In addition, a specially designed igniter chamber equipped with sapphire windows was used at EMI-AFB to study the fundamentals of the electrical discharge by means of high-speed photography.