Numerical study of swirl boundary layer flashback using LES-based tabulation method based on premixed and diffusion flamelet

Swirl boundary layer flashback is an important issue in practical swirl combustor design that may lead to severe device damages and deserves more attention. Here, a numerical study is performed to simulate partially-premixed methane/air flashback in a complex geometry of high-swirl combustor with a center body. The flashback mechanism is believed to be subject to the combined effect of large scale swirling flame front and small scale bulges of reverse flow, and is further complicated by the effects of fuel stratification and wall quenching. To account for the physicals, a large-eddy-simulation(LES)-based flamelet tabulation method is developed, and two types of combustion model, i.e. tabulation based on premixed flamelet and diffusion flamelet are incorporated and tested. Non-adiabatic effects are also introduced into the combustion model to account for wall heat loss. The performance of both models are first compared against each other under multiple levels of global equivalence ratio in terms of the initiation of flashback. Results are then compared with experimental data in terms of the flame front behavior and the speed of flashback.