Combustion modes of kerosene spray in a scramjet combustor with different injection schemes

Combustion modes of kerosene spray in a scramjet combustor condition with different injection schemes are experimentally investigated at Mach 2.52. The study is based on two single injectors with nozzle diameters of 0.79 and 1.14 mm and two dual injectors with nozzle diameters of 0.56 and 0.72 mm, respectively. The results show that the weak combustion mode has little effect on the flow field, while the intensive combustion mode has the opposite effect. The dual injector can promote evaporation and mixing of the kerosene spray. Compared with the dual injector, intensive combustion cannot occur when a single injector is used, and the flame stability range is also narrower. As the nozzle diameter of the injector increases, the distribution and oscillation of kerosene spray change significantly, transition from the weak to intensive combustion mode occurs at a higher equivalence ratio, and the flame stability range increases. However, change in the nozzle diameter does not affect the overall process of combustion mode transition. For the single injector, intensive combustion still cannot occur when the nozzle diameter changes. In addition, change in the nozzle diameter has little effect on combustion heat release when the combustion mode remains unchanged.