Influence of mixing model constant on local extinction effects and temperature prediction in LES for non-premixed swirling diffusion flames

The behavior of different viscous models on the non-premixed swirling diffusion flame and local extinction effect is investigated in this paper. A three dimensional numerical simulation is conducted on Sydney SMH1 flames using Wall-Modeled LES (WMLES) model, Kinetic Energy Transport model and realizable k-ε model coupled with laminar flamelet model. The scatter plots of temperature are analyzed when different mixing model constants Cvar are applied. Scalar dissipation rate theory is introduced to explain the influence of the Cvar on the local extinction prediction. The results of the present paper show that model constant Cvar has a significant effect on accuracy of prediction of the turbulent model. Among the three viscous models, the Kinetic Energy Transport model gives the best prediction on local extinction effect at the main recirculation zone. The analytic procedure may serve as a reference for further study on non-premixed swirling diffusion flames.