Analysis of the stabilization mechanisms and the NOx formation pathways of a partially premixed burner operated with pure hydrogen

Abstract

The need of reliable Computational Fluid Dynamics (CFD) models able to predict the performance of pure hydrogen combustion is becoming strategic for the development of new burner designs for Gas Turbine (GT) combustor. The ability to correctly assess the locations where the flame gets stabilized can also facilitate the early detection of any potential issue during the combustor operation, helping in the definition of the hardware improvements. So, in this research paper, the results of a species-transport based model applied to a partially premixed burner operated at atmospheric pressure will be presented as validation stage. This burner exhibits an attached and a lifted flame configuration depending on the flow conditions it operates with. The two test points are numerically investigated revealing an excellent agreement in terms of velocity field and heat release rate prediction compared with the experimental measurements. Lastly, the time-averaged CFD solutions are used to retrieve information for a Chemical Reactor Network (CRN) model employed to quantify the NOx emission leveraging a chemical mechanism able to consider all the possible formation pathways. It is demonstrated that the presented methodology is able to reproduce the experimental measures with high fidelity allowing to capture the relationship between flame morphology and pollutant emission formation.