Simulation of bi-Propellant Reaction Control Thrusters Based on Nitrous Oxide and Hydrocarbons

To replace highly toxic hydrazin-driven reaction control systems, a number of non-toxic alternatives are under development. These are usually referred to as “green propellants”. One candidate is the bi-propellant combination of nitrous oxide and hydrocarbons that combine good storability with a comparatively high specific impulse (ISP) at a medium to low system complexity level compared to existing hydrazine thrusters. This propellant combination was chosen because of experimentally available results with C2H4-N2O thrusters as validation data. One advantage of this fuel/oxidizer combination is that both gases are self-pressurant and that they can be used as monopropellants at a lower specific impulse ISP with reduced model complexity. This helps the design of the propulsion system on satellites. A detailed numerical simulation of a representative thruster based on the fuel combination ethylene and nitrous oxide is presented. The numerical model is set up with a suitable kinetic reaction mechanism for the simulation of the reactive mixture in the combustion chamber. It is validated against experimental data available in the literature.