MODULATION OF THE THICKENED FLAME MODEL INTO EDDY DISSIPATION CONCEPT FOR MULTIREGIME COMBUSTION MODELLING

The modelling of multi-regime turbulent flames is a challenging topic, especially when dealing with industrial burner designs under modern gas turbine conditions. Unfortunately, neither the reduced order combustion models (relying on the tabulated chemistry concept) nor the most computationally expensive ones (based on the species transport) are always predictive in describing the flame front characteristics. In the former approach, the tabulation of premixed or non-premixed flamelets is typically decided a priori, thus making the description of the multi-regime combustion process daring. On the other side, species transport-based turbulent combustion models are characterized by higher flexibility and do not have significant limitations. However, some of them are strictly valid only for specific combustion regimes: for instance, the Thickened Flame Model (TFM) is formally suitable only in the context of premixed combustion. In this work, in the framework of the species transport model, a novel hybrid closure is proposed: while the premixed part relies on the TFM, the non-premixed one is modelled using the well-known Eddy Dissipation Concept (EDC). The mathematical formulation as well as the validation of the approach against the experimental data – retrieved at atmospheric pressure and high oxidizer temperature of an industrial burner – will be presented.