ADN and AN solutions in hydrogen peroxide as green oxidiser for hypergolic propellants

In scope to replace hydrazine based hypergolic rocket propulsion systems, new green fuels and oxidisers are required. In this paper an approach is investigated basing on ammonium dinitramide (ADN) and ammonium nitrate (AN) solutions in high concentrated hydrogen peroxide in combination with energetic ionic liquids (EILs) as fuels. Hydrogen peroxide was concentrated via partial condensation. Such systems provide a theoretical specific impulse up to 2500 N s/kg per mass respectively 3600 N s/dm3 per volume and should suite as liquid or gelled propellants. Fuels based on EILs are characterized by reduced safety and handling hazards due to the very low vapour pressure of the liquid salts. Such fuels combined with solutions of ADN/AN in high concentrated hydrogen peroxide (H2O2) enable low operation temperatures below -40 °C. Assisted by appropriate catalysts integrated into the fuel, effective hypergolic propellant systems can be achieved. Hypergolic lab scale ignition tests result in ignition delay times comparable to hypergolic systems in operation. Measurements of combustion temperatures agree well with thermodynamic calculations of the adiabatic combustion temperatures indicating a good accordance with the predicted specific impulse.