A comparative study of different turbulence models for premixed NH3/H2 combustion in a swirl-stabilized burner

Combustion of ammonia (NH3) has emerged as an alternative to conventional fossil fuels due to its lower carbon footprint and potential as a clean energy carrier. In this study, a comparative analysis of different turbulence models for premixed NH3/H2 combustion in a swirl-stabilized burner was performed using computational fluid dynamics (CFD) simulations. The aim was to determine the most appropriate turbulence model for accurately predicting the flow, combustion and emissions characteristics of NH3/H2 fuel blend. The generic swirl burner being used in Cardiff University’s Gas Turbine Research Centre has been considered as validation test case. The simulations were performed using different turbulence models: the Realizable k-ε, the Renormalization Group (RNG) k-ε and the Reynolds Stress Model (RSM) turbulence models. A detailed chemical reaction mechanism was used for the premixed combustion of NH3/H2 using the Flamelet Generated Manifold (FGM) approach. The simulations were validated against experimental data. The results showed that all three turbulence models predicted the flame shape and location with reasonable accuracy, but the RSM model performed better than the other models in predicting the combustion characteristics and emissions. Specifically, the RSM model predicted a slightly higher flame temperature and a narrower flame front compared to the other models, which was consistent with the experimental data. The differences in the predicted combustion characteristics and emissions between the turbulence models were attributed to the differences in the modeling assumptions and closure models used in each model. In conclusion, the RSM turbulence model was found to be the most appropriate for predicting the combustion characteristics and emissions of premixed NH3/H2 combustion.