Electrical ignition of HAN-based liquid propellants.

The purpose of this paper and work reported herein is to contribute to the understanding of the fundamental physical parameters govering arcless electrical ignition of hydroxylammoniumnitrate (HAN) based liquid monopropellants (LP), especially LGP 1846 in conjunction with its use as propellant charge in the regenerative liquid propellant gun (RLPG). Further, to optimize igniter configurations with the goal of successfully igniting the LP charge of an actual 30-mm RLPG. The feasibility of arcless ignition in a 2 qcm igniter element was demonstrated in a 30-mm RLPG simulator. The igniter consists of a center rodlike electrode separated from a more or less conical vented outer electrode by a hollow cylindrical insulator. Simple steadystate potential field calculations were used. The energy uptake of the igniter is determined mainly by polarity, electrode surface area, and charge voltage. A stronger confinement of the liquid propellant igniter charge will speed up the ignition process. Sca nning electron microscopy (SEM) and x-ray microanalysis definitely show that ignition is affected by the chemical and physical characteristics of the electrode surface. Preliminary tests with a multi-channel IR-spectrometer monitoring the transient ignition reactions yielded encouraging results.