LES investigation of a swirl stabilized technically premixed hydrogen flame with FGM and TFM models

Climate change due to carbon emissions is one of the aspects that must be kept under control nowadays. In this fashion, the employment of hydrogen as fuel provides a fundamental solution for both power generation and transportation since lean premixed combustions allow to reset the carbon emissions and reduce the pollutant ones. Indeed, the higher reactivity of hydrogen permits to operate with a very low equivalence ratio which can drastically limit the NOx production with respect to the common fossil fuels. On the other hand, lean hydrogen mixtures are characterized by peculiar aspects that make their study through CFD simulations not straightforward. The present work aims to analyze through two different numerical approaches a technically premixed hydrogen flame experimentally investigated at the Technische Universität Berlin (TUB). In particular, the main differences between the Flamelet Generated Manifold and the Thickened Flame Model strategy are deeply analyzed as well as the effects of the thermal boundary conditions on the flame stabilization mechanism. The comparison with the experimental data shows the treatment employed drastically influences the accuracy of the obtained outcomes.