Numerical Simulations of the Combustion Process in a Research Thruster operating with N2O/C2H4 and Comparison to Experimental Data

Kurzfassung

Since decades, the highly toxic hydrazine is used as propellant for in-space propulsion. During the last years, several non-toxic alternatives – so-called green propellants – were developed. One promising replacement for hydrazine are mono- and bipropellants consisting of nitrous oxide and one or more fuels. Here, the German Aerospace Center (DLR) investigates a propellant consisting of nitrous oxide and ethane in premixed monopropellant configuration. In parallel to experimental work performed at DLR’s test site in Lampoldshausen, reaction mechanisms for the combustion of N2O/C2H4 and N2O/C2H6 were developed by DLR’s Institute of Combustion Technology. To gain insight in the combustion processes, the reaction mechanisms were used to simulate the combustion inside a research thruster. For modelling, the commercial CFD solver Ansys Fluent was used. In sum two different basic configurations were simulated: 1) The reaction of premixed N2O/C2H4 by employing the N2O/C2H4 mechanisms and 2) the reaction of premixed N2O/C2H4 by using the N2O/C2H6 mechanisms. As for all cases a large experimental database is available, the results of the simulations were directly compared to the experimental results regarding chamber pressure, thrust and wall heat flux. To match the experimental data, different reaction and turbu- lence models were used and evaluated. Depending on the specific model selection, a very good agreement of the simulation data with the experimental results was achieved.