Low-NOx combustors for hydrogen fueled aero engine

Against the background of increasing environmental concerns analytical modelling and experimental tests on low-NOx hydrogen combustors for aero engines have been conducted within the Euro-Quebec Hydro-Hydrogen Pilot Project (EQHHPP). This project is jointly supported by the European Union and the Government of Quebec. This is a 4 year program started in 1992; the objectives are to establish the NOx reduction potential and to provide design guidelines for later development of real aero engine combustors. The paper discusses the findings from phase III.0-2 (demonstration phase) of this program [1]. Various candidate fuel preparation concepts for lean hydrogen combustion with and without fuel/air premixing have been evaluated in a generic can type combustor at Pratt & Whitney Canada (PWC). Significant reduction in NOx emissions at simulated representative engine conditions has been achieved. Two concepts were then selected for further investigation in a research type combustion chamber which represents a typical 60 degrees sector of a modern annular combustor. A test rig has been built by MTU especially for these tests. Steady state testing is being performed at Daimler-Benz Aerospace. Further tests to study the transient behaviour have been conducted by United Technologies Research Centre (UTRC). In addition, kinetic modelling was performed at Deutsche Forschungsanstalt fur Luft- und Raumfahrt (DLR) and PWC to provide a useful design tool for low-NOx hydrogen combustors.