Experiment on kerosene fueled scramjet ignition by using plasma torch

Liquid kerosene ignition was explored in a direct-connected scramjet test facility,that the entrance flow Mach number of the combustor was 2.5,and the total temperature was 1650K.Using a plasma torch with 1.5kW input power,kerosene ignition and sustain combustion realized without any pilot hydrogen.Fuel injection pressure and injector location were investigated as factors affecting the ignition performance.The test results indicate that successful ignition can be achieved when the injectors are located 550mm,upstream the ignition cavity and the fuel injection pressure is between 1.5-2.3MPa.It is also found that higher injection pressure and shorter distance between injection location and the cavity brings negative effects to ignition.Therefore,local fuel-air-ratio is considered as one of the main factors of ignition.Based on the high-speed images of ignition and combustion,it is indicated that the downstream cavity does not advance ignition at the beginning period of the ignition but is very important for sustain combustion and flame propagation.