喷口导流环结构对激波聚焦起爆的影响分析

Investigation on the Effects of Deflector Structure on Detonation Initiation by Shock Wave Focusing

关键词:  脉冲爆震发动机  导流环  激波聚焦  数值仿真

Key words:  Pulse detonation Deflector  Shock wave focusing  Numerical simulation

摘要:

为研究两级脉冲爆震发动机环形喷口导流环的深度与角度对共振腔内激波聚焦起爆爆震波的影响,以氢气和空气混合物为例,对不同导流环深度和角度下激波聚焦起爆爆震波的过程进行了数值模拟。结果表明,导流环越深,起爆点的压力和温度越高,越有利于起爆；在导流环角度较小的情况下,导流环越深,工作频率越低,单位时间内整个装置的净冲量越小；在导流环角度较大的情况下,导流环越深,工作频率越高,单位时间内整个装置的净冲量越大；此外,随着导流环倾斜角的增大,起爆点温度和压力先升高后降低,在倾斜角为25°左右达到最大值,且起爆时刻提前,工作频率提高,单位时间内整个装置的净冲量也增大。 

Abstract:

To investigate the effects of depth and angle of deflector on detonation initiation via shock wave focusing in a 2-stage PDE, detonation initiation with different deflector depth and angle was simulated and hydrogen-air mixture was used in this study. The results indicate that a deeper deflector has a favorable effect on detonation initiation and can produce higher temperature and pressure at initiation point. When the deflector angle is small, the operation frequency and the net impulse of the device as a whole per second decrease as the deflector becomes deeper. With the deflector angle increasing, however, a deeper deflector corresponds to higher operation frequency and net impulse. In addition, as the deflector angle increases,both temperature and pressure at initiation point undergo an increase first, obtaining maximal value at 25°,and then followed by decreasing a increasing deflector angle also produces an earlier initiation moment, increase of operation frequency and net impulse.