Numerical calculation of heat flux profiles in a N2O/C2H4 premixied green propellant combustor using an inverse heat conduction method

With the aim to replace toxic propellants like hydrazine, an effort has been placed in the investigation of human- and environment-friendlier substances called “Green Propellants”. Within the context of this research initiative and in terms with the REACH-Regulation, the German Aerospace Center (DLR) in Lampoldshausen is developing and testing an experimental demonstrator based on the technology of a premixed nitrous oxide/ethene (N2O/C2H4) propellant. The advantages of this propellant include high specific impulse and low toxicity but are accompanied by several challenges like the high combustion temperature (up to 3300K), which directly influences the thermal design of an engine. For a better understanding of the combustion processes in the premixed propellant and a better estimation of the thermal loads on the thruster material, an accurate calculation of the heat flux in the combustion chamber is required. For this purpose an inverse heat conduction method developed at the Technical University of Munich (TUM) was utilized. Based on the thermocouple measurements in the chamber material, the time-dependant heat flux profiles were calculated using an Iterative Regularization Method (IRM). Heat flux and temperature results for different pressure load points were obtained, thereby helping to characterize the combustion properties of the propellant combination.