Exploring the influence of additives on the ignition, combustion and quenching of electrically controlled solid propellants

Abstract

The influence of additives on the decomposition and combustion characteristics of electrically controlled solid propellants was investigated through small scale experiments. Carbon black and aluminum additives were explored in a polyethylene oxide, lithium perchlorate propellant. Additives were used to improve the voltage response and their impact on ignition and combustion was characterized. The data showed that conductive additives can mitigate the loss of solid phase conductivity through solvent evaporation and that ignition delay decreases with higher voltage and solid phase conductivity. Steady‐state combustion experiments showed that electrical decomposition of the propellants proceeded more rapidly than a purely thermal stimulus illustrating the importance of electrochemistry in ECSP combustion. The combined effects of pressure and voltage on combustion rates were summarized in Saint‐Robert's burn relations. The regression rates increased with both applied voltage and pressure. The pressure deflagration limit of propellants with the carbon black additive was significantly reduced compared to a neat PEO/LP propellant, whereas the addition of 10 % aluminum did not affect the pressure deflagration limit.