基于乙烯或氢气的吸气式旋转爆轰发动机实验

Experimental on Air-Breathing Rotating Detonation Engine Using Ethylene or Hydrogen

基于氢气的旋转爆轰发动机研究较多,而碳氢燃料与空气混合较为困难,导致基于乙烯的旋转爆轰发动机燃烧技术难度很高.使用宽视野范围的可视化燃烧室观察旋转爆轰波的研究在国内尚未开展.在同一燃烧室内进一步开展了乙烯或氢气的吸气式旋转爆轰实验,来流总温为283～284 K,燃烧室壁面有140°石英玻璃观察窗,便于观察旋转爆轰波运动过程.空筒燃烧室爆轰环腔外径为100 mm,轴向长度为151 mm.燃料通过150个直径0.8 mm圆柱孔进入燃烧室,空气通过喉部1 mm宽的收敛扩张环缝流入环腔.高速摄影和低高频压力传感器均验证了旋转爆轰波的存在和速度值.以氢气为燃料的旋转爆轰波速度最高可达理论值的101%,爆轰波增压效应可达40%左右,乙烯旋转爆轰波速度可达理论值的89%.旋转爆轰波结构容易发生变化,不规则.氢气旋转爆轰的维持对燃烧室的结构要求比碳氢燃料要低,比乙烯旋转爆轰波更加稳定.

Though a lot of study has been carried out on hydrogen-air rotating detonation engine,combustion technologies are still difficult due to the difficulty of mixing for hydrocarbon fuels and air.Rotating detonation waves in an optically accessible combustor with a wide observation window have not been studied in China.Ethylene or hydrogen air-brathing rotating detonation tests with inlet total temperatures 283~284 K were conducted in the present study.The detonation channel of the hollow combustor has an outer diameter of 100 mm and a length of 151 mm.Fuel and air were injected into the combustor from 150 cylindrical orifices of a diameter of 0.8 mm and a convergent-divergent circular channel with a throat width of 1 mm,respectively.A piece of quarts glass of 140°was mounted in the outer wall of the combustor to observe the detonation wave.High-speed imaging and pressure traces both proved the detonation speeds.The hydrogen detonation speed could be as high as 101%of CJ values and the pressure gain is as high as 40%.The ethylene detonation speed was up to 89%of the theoretical value.The detonation structure is changeful and irregular.Hydrogen-air rotating detonation sustenance is easier than hydrocarbon-air one.Hydrogen detonation is more stable than ethylene one.