Modelling of Turbulent Hydrogen Combustion including Preferential Diffusion Effects for Gas Turbine Applications

Due to the global rise in temperatures, the need for clean and renewable fuels is higher than ever. The irregular nature of energy generated by wind and/or photovoltaics poses challenges in establishing a stable electricity grid, and additional flexible power sources are necessary to stabilize the grid. A gas turbine is a good example of such a flexible and reliable power source. However, the gas turbines currently in use operate solely on natural gas. A crucial step in decarbonising the power generation sector is to retrofit gas turbines so that they can cope with green gaseous fuels, such as hydrogen. Hydrogen seems to be a viable solution due to the absence of carbon in its molecular structure. However, the combustion properties of hydrogen are vastly different relative to natural gas, and therefore design adaptations might be necessary. To effectively design combustion systems that operate on hydrogen, efficient and accurate predictive CFD models are required. This research is part of the EU HELIOS project, which is fully entitled: “Stable high hydrogen low NOx combustion in full scale gas turbine combustor at high firing temperatures”. The main focus of this research is to create high-fidelity turbulent hydrogen combustion models for gas turbine applications. The combustion models will be based on the tabulated reduced chemistry method, the Flamelet Generated Manifold (FGM) method [1], and extended to take the large preferential diffusion effects of hydrogen into
account. The interaction between turbulence and chemistry will be investigated by performing direct numerical simulation (DNS) of premixed hydrogen with detailed reaction mechanisms. The analyses of the DNS results will guide the development of the reduced order large eddy simulation (LES) turbulence model to come to an accurate and efficient FGM-LES tool [2]. The FGM-LES tool will be validated on experimental data obtained by laser-diagnostics measurements performed on a lab-scale model of a gas turbine combustor. When the tool is validated, phenomena such as flame stabilization and flashback will be investigated to obtain a deep understanding of turbulent hydrogen combustion. No specific results are there to be shown yet, since the research project has only started recently.