Absorption Spectroscopy of NO in Hydrogen Combustion based on Heterodyne Techniques using Quantum Cascade Lasers

Currently, a worldwide growing willingness to dramatically reduce the environmental impact of civil aviation within the next decades is noticeable. At the same time the need of improve-ment of current civil transport aircraft performance is urging the scientific and engineering community to foster international cooperation with the final goal of developing new high-speed vehicles. The H2020 STRATOFLY (Stratospheric Flying Opportunities for High-Speed Pro-pulsion Concepts) project funded by the European Commission, under the Horizon 2020 framework was set up to study the feasibility of high-speed passenger stratospheric flight. Technological, environmental and economic factors that allow the sustainability of new air space’s exploitation are considered to drastically reduce transfer time, emissions and noise, and to guarantee the required safety levels. The experimental determination of production of NO and H2O during hydrogen combustion in modern propulsion systems is the part of the contribution of the German Aerospace Center to the STRATOFLY project. The measure-ments will be performed in the High Enthalpy Shock Tunnel Gottingen (HEG), one of the major European hypersonic test facilities. The combustion process within the propulsion unit of a small scale flight experiment wind tunnel model of the LAPCAT MR2 vehicle will be studied employing absorption spectroscopy techniques with infrared laser light. The test time for experiments in HEG is typically around several milliseconds and therefore the spectro-scopic technique has to offer high acquisition rates, in this case up to 250 kHz.