填充系数对脉冲爆轰发动机爆轰噪声影响的实验研究

为探索不同填充系数下气液两相脉冲爆轰发动机爆轰噪声特点,搭建了能够准确调节气液两相脉冲爆轰发动机填充系数的噪声测试实验系统,对800 mm和3000 mm处不同角度下脉冲爆轰发动机爆轰噪声特性进行了研究。结果表明,随着填充系数的增加,冲击噪声幅值与射流噪声幅值随之增大,但射流噪声幅值与冲击噪声幅值的比值降低;在爆燃与爆轰的转折点,冲击噪声幅值与射流噪声幅值显著增加;爆燃阶段下的冲击噪声幅值与射流噪声幅值增加速率小于爆轰阶段;随着距离的增加,填充系数对冲击噪声与射流噪声的增强作用有所减弱,冲击噪声的衰减速度快于射流噪声;随着填充系数的增加,当距离较小时指向性明显,当距离较大时指向性不明显。

Effect of filling fraction in the noise characteristic of pulse detonation engine

The experiment system of gas-liquid two-phase pulse detonation engine, where filling fraction could be regulated accurately, was set up to investigate the detonation noise characteristic with different filling fractions. The experiment was carried out in 800 mm and 3000 mm at four angles. The results show that as the filling fraction increasing, there are increases in amplitudes of impact noise and jet noise at all angles, without an increase in the amplitude ratio of jet noise and impact noise. A significant increase in amplitude of impact noise and jet noise are observed at the turning point from deflagration stage to detonation stage. The amplitude of impact noise and jet noise are slow increase in deflagration stage, but significant increase in detonation stage. With increased distance, the enhancement of filling fraction in impact noise and jet noise are shown down and the decay rate of jet noise is slower than impact noise. With increased filling fraction, the detonation noise directivity becomes obviously at short distance, but ambiguously at long distance.