Visualization on spray distribution of close-coupled fuel injector and strut with cavity flameholder system

Spray distribution is closely related to the fuel supply methods, fuel-air distribution ratio, flame stability and flame propagation properties of flameholders. Taking RP-3 as atomization medium, the spray distribution characteristics of close-coupled fuel injector and strut with cavity flameholder system were visualized by high-speed photography and laser sheet/photography, under the condition of incoming flow Mach number 0.2, incoming flow temperature varying from 10℃ to 400℃, the distance of fuel injector and stabilizer kept as 31.5mm and the downstream injection direction. Meanwhile, the effects of incoming flow temperature and fuel-to-air momentum flux ratio on spray distribution trajectory were studied as well. The result showed that, downstream injection close-coupled fuel injector and strut with cavity folder system was benificial to the fuel atomization by splashing fuel jet at the leading edge of strut. After the splashing, a part of fuel was distributed on the surface of strut as fuel film and atomized further at the leading edge and trailing edge of cavity, during which higher incoming flow temperature led to faster evaporation. And another part of fuel spray was atomized as cross-flow. Under the same incoming flow temperature, the axial-direction distribution distance and cross-direction penetration depth of spray increased with the fuel-to-air momentum flux ratio. With the increase of air incoming flow temperature, penetration depth increased and fuel-to-air momentum flux ratio's effect to spray distribution became more obvious.