Effect of voltage and droplet size on electrical ignition characteristics of ADN-based liquid propellant droplet

Abstract

To remove the dependence of ammonium dinitramide (ADN)-based liquid space engine on the catalyst, a new thermal ignition method was developed for ADN-based liquid propellant resistant to ignition. Experiments of ADN-based liquid monopropellant droplets were carried out in a constant-volume chamber. Ignition delay time and combustion duration were defined to study the electrical ignition characteristics of single droplet. The results show that the ADN-based liquid propellant droplets could be ignited using the current thermal effect of droplets after electrification at appropriate voltage. Droplets were accompanied by bubble formation and gases escape from the droplets during evaporation, decomposition, and combustion. With the increase in voltages, the ignition delay time and combustion duration of ADN-based liquid propellant droplets decreased with the increase in voltage overall when the initial volumes of droplets were 4.189 μL. The ignition delay time of droplets increased with the increase in the initial volume of droplet. The combustion duration of droplets showed fluctuant variation trend with the increase in the initial volume of droplet. When the initial volume of droplet increased to a certain extent, combustion self-sustainment could not be achieved at the later stage of combustion.