Effects of Fuel Injection on Flame Propagation of Cavity-Based Strut Flameholder

Flame propagation of flameholder is very important for the estimation of combustion efficiency and combustor length. Based on experiments verification, effects of fuel injection position, fuel injection angle and fuel air ratio on the flame propagation of the cavity -based strut flameholder were analyzed by 3D numerical simulation, according to the temperature distribution and ions mole fraction distribution information downstream the flameholder. Under the condition that inlet temperature is 900℃, inlet Ma is 0.2, pilot fuel air ratio is 4×10^-3 and mainstream fuel air ratio is 2.8×10^-3~6.8×10^-3, the results show that, the temperature and the ions mole fraction downstream the flameholder have similar distribution, and can be used to analyze the flame propagation simultaneously. It's positive to flame propagation when the pilot fuel injection position is closed to the leading edge of flameholder. In the condition of fuel air ratio being 2.8×10^-3, closer mainstream fuel injection position to the leading edge of flameholder or perpendicular injection angle to the main stream is more beneficial to the flame propagation. While with the increasing of fuel air ratio to 5×10^-3~6.8×10^-3, flame propagation ability increases when the mainstream fuel injection position is away from the leading edge of flameholder or the injection angle is parallel to main stream. In the same fuel injection angle condition, fuel injection position strongly impacts the flame propagation via changing of fuel air ratio. However, in the same fuel injection position, the influence of fuel air ratio on the flame propagation is relatively small with the change of injection angle.