Goal:
Operation of a small jet engine with hydrogen to avoid CO2 emissions during flight.

Overview:
The objective of the Hy4JetEngines-project is to adapt the combustion chamber of a jet engine in the thrust range of 1kN for hydrogen combustion. The use of hydrogen from renewable sources as chemical energy carrier is a promising approach with a carbon-free energy conversion. It thereby reduces the environmental impact significantly.
To reduce the CO2 foot print of jet engines hydrogen instead of kerosene is investigated for combustion. The combustion of hydrogen just generates water as main combustion product with a small amount of nitrogen oxides. For the use of hydrogen the combustion chamber of the gas turbine has to be adapted. To achieve a combustion chamber design for stable hydrogen combustion as well as low nitrogen oxide emissions it is necessary to consider the specific properties of hydrogen, like high flame speed and high reactivity. Therefore numerical 2D and 3D simulations of the proposed design are done. Furthermore, a scaled version of the adapted combustion chamber will be used for experimental validation of the numerical investigation at the hot flow test facility of the Institute. To validate the emissions in the exhaust gas measurements according to ICAO standards will be used.
A functional jet engine with kerosene combustion is available at the jet engine testbed of the institute and can be adapted for the use of hydrogen combustion. Beside the combustion chamber, the rotor bearings and the jet engine controller have to be adapted at that specific aero engine. The use of hydrogen instead of kerosene as fuel makes a closed lubrication circuit of the bearings necessary. Therefore the bearing concept of the turbine has to be changed e.g. into plain bearings. Simultaneously the emissions can be lowered as with this modification no unburned fuel-oil-mixture is used as lubricant, as in the actual kerosene powered engine. After integrating the new designed combustion chamber as well as the adapted bearings and engine controller it can be tested as a complete system.

Publications
Borm, O., 2014. “Evaluation of gaseous emissions from hydrogen combustion aircraft engines”. Proceedings of ASME Turbo Expo 2014, Düsseldorf, Germany, GT2014-25470.
Malli, H., Eckerstorfer, K., Borm, O., 2014. “Experimental and numerical investigation of a combustion chamber under various inlet conditions”. Proceedings of ASME Turbo Expo 2014, Düsseldorf, Germany, GT2014-25472.
Mastrodonato, A., Borm, O., 2014. “Impact of the Air to Fuel Jet Momentum Ratio on the NOx Emissions of a Hydrogen Combustion Chamber”. Proceedings of the European Combustion Meeting 2015, Budapest, Hungary.