Development of a Hydrogen Micro Gas Turbine Combustor: Atmospheric Pressure Testing

Abstract In the H2mGT project, funded by the German BMWK, a micro gas turbine (mGT) burner with 100% hydrogen firing is developed and validated. The project is a collaboration between TUB and the manufacturer Euro-K GmbH. It consists of three phases: 1. Atmospheric pressure tests with optical access; 2. Atmospheric pressure tests with secondary air injection; 3. Validation of the burner in the mGT. This paper will present the results of Phase 1. The hydrogen burner is based on a swirl-stabilized burner of TUB. The burner design features multiple geometrical parameters to enable the optimization towards low NOx emissions. Therefore, a variable swirl intensity, additional axial momentum of air in the mixing tube, a movable center-body and different fuel injection locations are implemented. Phase 1 investigates the parameter space in terms of flame stability, operational range and parameter impact on flame shape and emissions. It is found that the flame can be operated over a large range of equivalence ratios and preheating temperatures up to 500°C for many parameter settings. However, at some geometries flashback into the mixing tube is triggered. As expected, the NOx emissions are mainly influenced by the equivalence ratio, the fuel distribution, and the swirl intensity. Single digit emissions are reached up to an equivalence ratio of 0.4 at atmospheric pressure conditions. Furthermore, the burner can be operated at 100% natural gas or 100% hydrogen without any geometry changes without a significant change in NOx emissions.