吸气式无阀脉冲爆震发动机试验研究

Experimental investigation of air-breathing valveless pulse detonation engine

为了获得大气层内的高速巡航能力,需要发展包括吸气式脉冲爆震发动机在内的多种新概念动力装置。设计制造了完整的吸气式无阀脉冲爆震模型机,包括亚声速进气道,混合室,点火室,爆震室和喷管。采用起爆性较差的汽油和空气为推进剂,以低于50mJ的点火能量研究了模型机(除去喷管)的多循环单级起爆和爆燃向爆震转变过程(DDT),并尝试减小DDT轴向距离的方法。设计一种环缝结构来加强汽油、空气的掺混,和减小推力壁端敞口对模型机起爆的不利影响。试验表明模型机易于起爆,DDT距离在1.3m(距离点火器)左右,采用高能点火装置之后,DDT距离减为1.09m。模型机与一端封闭一端敞开的脉冲爆震火箭发动机相比,由于两端敞口,各测压点压力时域变化更加复杂,有两次上升和下降过程。

Revolutionary concept propulsion systems including air-breathing pulse detonation engine （PDE） are required in order to achieve high-speed cruise capability in the atmosphere. An air-breathing valveless PDE model was designed and manufactured, which was made up of subsonic inlet, mixing chamber, ignition chamber, detonation chamber and nozzle. And the proof-of-principle experiments of PDE model were successfully carried out, by using liquid gasoline-air mixture with low-energy system （total stored energy less than 50m J）. The air was supplied upstream of the air inlet by a semi free flow-field. A circumferential seam config- uration collecting the inlet with mixing chamber was used to increase the mixing degree of gasoline/air and reduce the bad effect of air inlet on detonation initiation for detonation is difficult to initiate in the tube with two end open. The measured detonation wave pressure ratio was very close to that of C-J detonation. The air- breathing PDE model was easy to initiate and worked in good condition. The deflagration to detonation transition （DDT） and two methods to reduce DDT distance were also investigated. The results indicated the DDT distance was about 1.3m （from the ignitor） and it was reduced to 1.09m when the ignitor with higher energy was used. Compared to pulse detonation rocket engine （PDRE） with one end close and one end open, the evolution of pressure at different positions along the air-breathing model is more complicated with twice rising and twice falling.