Instrumentation, Modeling, and Testing of a Gas Turbine Engine Using Lean Premixed Hydrogen Combustion

A Pratt and Whitney PT6A-20 turboprop engine has been modified to burn pure gaseous hydrogen in lean premixed mode. The modification of the engine’s combustor to allow premixed hydrogen-air combustion necessitated additional modifications to the engine and fuel system to provide a high level of feedback and control. An engine test rig has been assembled that includes a water brake dynamometer and a hydrogen supply system that allows safe, precise control of the fuel flow to the premixers. Additionally, instrumentation has been put in place to monitor the critical aspects of engine, premixer, and fuel system operation. Significant data has been gathered from engine runs on both Jet-A and hydrogen. A computer cycle analysis model has been created and used to examine the performance of the modified engine. The combination of engine test data and computer modeling provided insight into the operating conditions of the premixers in the modified engine, as well as the effects of the combustor modifications on engine performance.