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

Abstract

In order 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 (I$_\text{SP}$) at a medium to low system complexity level compared to existing hydrazine thrusters. This propellant combination is chosen because of experimentally available results with C$_2$H$_4$-N$_2$O 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 mono-propellants at a lower specific impulse I$_\text{SP}$ with reduced model complexity. This helps the design of the propulsion system on satellites. The focus of this investigation is the detailed numerical simulation of a representative thruster based on the fuel combination ethane and nitrous oxide. The numerical model is set up with a suitable kinetic reaction mechanisms for the simulation of the reactive mixture in the combustion chamber. It is validated against experimental data available in literature.