U型脉冲爆震燃烧室的点火起爆工作特性试验研究

Experimental Investigation on Ignition and Detonation Characteristics of U-Bend Pulse Detonation Combustor

为缩短脉冲爆震燃烧室轴向长度,开展了气液两相U型脉冲爆震燃烧室(U-PDC)点火起爆特性试验研究。试验时采用火花塞点火和热射流点火,且点火能量可调。研究结果表明,两种点火方式均可实现U-PDC工作频率10~30Hz稳定工作,且爆燃向爆震转变DDT的时间随工作频率提高而缩短,为5~11ms。此外,实现U-PDC稳定工作时,热射流所需的点火能量为0.05J,较火花塞点火能量1J更低,并且热射流点火DDT距离更短,约718mm,起爆位置距来流入口的轴向距离约280mm,缩短了起爆所需的轴向长度,有利于工程应用。进一步提高热射流点火能量,其DDT距离无明显变化。

In order to shorten the axial length of pulse detonation combustor(PDC),experimental study on the ignition and detonation characteristics of a gas-liquid two-phase U-Bend pulse detonation combustor(UPDC)was carried out.Spark plug ignition and hot jet ignition were used in the experiment.The ignition energy is adjustable.The results indicate that the two ignition modes can achieve the stable operation of the U-PDC at the working frequency of 10~30Hz.The deflagration to detonation transition(DDT)time decreases with the increase of the working frequency,ranging from 5ms to 11ms.In addition,when the U-PDC works stably,the ignition energy required by hot jet is 0.05J,which is lower than that of spark plug ignition energy(i.e.1J).The DDT distance of hot jet ignition is shorter,about 718mm.The axial distance between detonation initiation position and the inlet is about 280mm,the shorter axial length required for detonation initiation is benefit for engineering application.However,the DDT distance sees no great variation when the ignition energy of hot jet further increases.