ZURUECK HOCH VOR INHALT SUCHEN

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Proposing Institution

Institut für Technische Verbrennung, RWTH Aachen
Project Manager

Lukas Berger
Templergraben 64
52056 Aachen
Abstract
Gas turbines are a crucial contributor to the world’s power capacity. In the future, the role of gasturbines in electricity generation in Germany will become even more important, as gas turbine powerplants have been identified as a potential replacement for nuclear power plants. The vision “Energiekonzept 2050“ by the German government emphasizes the importance of stationary gas turbines as it aims to increase the share of high hydrogen content (HHC) fuels, for example syngas from coal gasification. Such fuels will become more important in the future, but have a combustion behavior that is entirely different from commonly used fuels, such as natural gas. Currently, the use of CFD (Computational Fluid Dynamics) is gaining importance in the design of modern gas turbine combustors in order to realize the full potential of low emissions combustion systems. Nonetheless, the increased use of CFD as a design tool for future gas turbines requires models that are accurate yet affordable.Within the Sonderforschungsbereich (SFB 686), we are developing LES (Large-Eddy Simulation) models for turbulent premixed combustion that will be used for the design of future gas turbines. Recent reviews highlight the potential of LES of turbulent combustion. The proposed project addresses various issues of turbulent combustion using LES for accurately predicting transient flame behavior in lean premixed gas turbine combustors with the specific challenge of fuel flexibility. Specifically, HHC fuels develop thermal-diffusive combustion instabilities, which substantially alter the combustion process and its interaction with turbulence. This leads to problems when operating gas turbines with HHC fuels, especially when the hydrogen content can vary. Current modeling approaches developed for hydrocarbon fuels cannot describe the complex phenomena occurring under these conditions. We propose a comprehensive approach that starts with direct numerical simulations (DNS) of lean hydrogen combustion in order to understand and model the intricate interactions of flame structure, thermal-diffusive instabilities, and the turbulence. In the following, we will investigate CH4-H2 mixtures with varying hydrogen content. These simulations will provide data for subsequent LES model testing and validation. Model development will start with a two-scalar model that we have developed in prior work. The newly developed models will be tested in a priori and a posteriori studies using the DNS data. The models will finally be assessed in large-eddy simulations of a hydrogen-fueled low swirl burner and compared with experimental data.

Impressum, Conny Wendler