Microwave Controlled Ignition and Combustion Characteristics of ADN-based Ionic Liquid Propellant with Fast Response and Environmental Friendliness

The ADN-based ionic liquid propellants have been successfully implemented in liquid rocket engines, owing to high specific impulse and thrust, low toxicity and environmental friendliness. However, the traditional catalyst ignition of ADN-based propellant suffers from the problems of catalyst deactivation problems in the heating process. Microwaves could interact with the material holistically due to excellent penetration ability. Compared with solid materials, ionic liquids are natural microwave receptors on account of great polarity. To date, the possibility of microwave ignition of ionic liquid materials has not been explored. In this work, two kinds of ionic liquids: ADN and [AMIM][DCA] were used as oxidant and fuel of liquid propellant to achieve the maximum microwave absorption effect. The microwave controlled ignition and combustion of ADN-based liquid propellant was first realized and systematically studied. Compared to single component, the heat release, gas production, conductivity and heating rate of the mixed system was greatly enhanced. The sample (ADN/[AMIM][DCA] 10%) was successfully ignited by microwaves, displaying a decreased ignition delay time at higher power inputs. The ignition was generated in the gas phase and rapidly diffused into the solution, and the extinguishment was highly consistent with the input cessation of microwaves. The ignition delay was significant reduced in repeated ignition, resulted from the faster moving speeds of ions. The successful realization of microwave controlled ignition and combustion of ADN-based IL propellant will broaden the scope of their applications in space fuel and provide a new direction for the reform of liquid engines.