COMBUSTOR – TURBINE STATOR INTERACTION IN HYDROGEN FUELLED MICRO GAS TURBINE

The current trend to global decarbonization induces the employment of alternative fuels in micro gas turbines. Among these fuels, hydrogen or hydrogen-enriched blends have been considered as one of the main attractive solutions for having fewer pollutant emissions with the same or better combustion performance compared to natural gas. Therefore, the effect of natural gas-hydrogen blended fuel on the combustion performance of a reverse flow combustor is performed by CFD numerical simulations. However, the enhanced flame speed of hydrogen can cause unstable phenomena that, in addition to the periodic unsteadiness of the stator – rotor interaction, lead to a performance decay. In this paper the effect that some critical combustion regimes exert on the combustor – stator interaction in a reverse flow burner are discussed. A preliminary assessment of flow analysis aims at the selection of the most appropriate turbulence model: the results of k-epsilon model, detached and large eddy simulation are compared. The turbulence – chemistry interaction is analyzed by means of a flamelet generated manifold scheme under the hypothesis of partially premixed combustion. The combined solution of Cequations allows identification of the fluctuations of the flame front location, which is considered the main origin of pulsating reacting flow.