超声速气流中煤油射流的等离子体点火实验

在直连式超燃实验台上开展来流马赫数为2.5,总温为1650K的液态煤油燃料点火实验.在未使用引导氢气的情况下,利用输入能量为1.5kW的电弧等离子体炬实现煤油可靠点火和稳定燃烧.研究了煤油的不同喷注位置、喷射压力对点火性能的影响.实验表明:燃料喷口距离点火凹腔为550mm,喷射压力为1.5~2.3MPa时,可成功点火,更近的喷射位置和更高的喷射压力无法点火,分析认为点火凹腔的局部混合特征是影响点火的关键因素.根据点火和火焰前传的高速摄影图,发现下游凹腔在点火初期的作用不大,但是对于稳定燃烧和火焰前传有重要作用.

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.