Flame propagation and flashback characteristics in a kerosene fueled supersonic combustor equipped with strut/wall combined fuel injectors

Flame propagation characteristics in a liquid kerosene fueled supersonic combustor were observed in this paper. The strut/wall combined fuel injection scheme was used to achieve the multi-staged fuel injection, and the thin strut was also adopted as the flame holder. A series of experiments and numerical simulations were carried out in the condition of Ma=2.8. In order to represent the flame characteristics during the flame propagation process, high-speed photography and pressure measurement were taken to record the data. Based on the basic date, the variation of flame area and Mach number distributions during the experimental process were analyzed, and the flowing field characteristics were also discussed according to the numerical results. Results indicated that the core flame would diffuse to the primary flow with the increasing of equivalence ratio, enlarging the flame width. The flame flashback phenomenon of both core flame and wall flame, induced by the flame propagation, was detected and analyzed. Then, the interaction between combustion and flowing in the supersonic combustor was investigated, based on which, the mechanism of flame flashback phenomenon was also revealed. Numerical results showed that the generation of recirculation and low-speed region in boundary layer was the inducing mechanism of flame flashback. With the investigations in this paper, a depth understanding of the flame propagation process in supersonic airflow was achieved, based on which, a further optimization of combustion performance could be conducted.