Numerical Simulation Of Flame Flashback In The Lean Direct Injection Combustor

Flashback is such a phenomenon that the flame propagates from the combustor into the mixing zone, it contains complex interactions between combustion and turbulence.It is also one of the key issues in combustion research.In this paper, lean direct injection combustor was used for study. Large-eddy simulation and mixture fraction/PDF equilibrium chemistry model were adopted for investigating flashback in the LDI combustor, and the mechanism of flashback was analyzed. Meanwhile, the interaction between the flame and the flow field was also taken into account.The cold flow in LDI combustor has been calculated by LES, the results show that the calculated values are in good agreement with the experimental values, there is a central recirculation zone in the combustor under the action of strong swirling flow.Then, using large eddy simulation and mixture fraction/PDF equilibrium chemistry model simulated the stable flame. The simulation results show that the central recirculation zone plays a good role in stabling the flame.By changing the inlet flow rate and equivalence ratio, the flashback was observed. Through analyzing the flame motion and the changes of axial velocity field during flashback, we found that: flame flashback in LDI combustor occurs around the centerline and during flashback, the central recirculation zone moves upstream and earlier than the flame propagation, which pulls the flame upstream propagation, and the interaction between flow and flame pushes the flame propagation farther upstream, finally leads to flashback.