喷管对脉冲爆轰发动机爆轰噪声影响的实验研究

喷管不但可以增加脉冲爆轰发动机推力，而且对脉冲爆轰发动机噪声的形成与传播也具有重要作用。为探索脉冲爆轰发动机爆轰噪声形成机理及控制技术，搭建了脉冲爆轰发动机噪声测试实验系统，在不同位置不同角度对3种不同类型喷管的脉冲爆轰发动机爆轰噪声特性进行了研究。研究结果表明，收敛扩张喷管对于减小脉冲爆轰发动机爆轰噪声幅值作用最为明显，在0°方向3 000 mm处可以达到77.13%的降幅；对于收敛喷管，收敛角度越大指向性越明显，而扩张和收敛扩张喷管的喷管出口面积越大指向性越不明显；喉部直径48 mm的收敛扩张喷管与管口直径280 mm和320 mm的扩张喷管对参考半径影响最为显著，参考半径由1 600 mm减小至800 mm. 研究结果对于爆轰噪声机理研究以及脉冲爆轰发动机工程化应用具有重要参考意义。

Research on the Noise Characteristic of Pulse Detonation Engine with Nozzles

As an effective approach to improve the thrust performance, the nozzle plays an important role in the control of formation and propagation of pulse detonation engine noise. The experimental system of pulse detonation engine is set up to investigate the formation and control method of detonation noise. The detonation noise characteristic of pulse detonation engine with three nozzles is studied. The results show that the convergent-divergent nozzle has the most significant influence on pulse detonation engine noise to reduce the noise amplitude by 77.13% in 0 ° direction and at 3 000 mm. Large convergence angle would lead to obvious directivity for convergent nozzles. The obvious directivity would be also obtained by divergent and convergent-divergent nozzles with small exit area. The convergent-divergent nozzle with 48 mm throat diameter and the divergent nozzles with 280 and 320 mm exit diameters have the significant impact on reference radius which is reduced from 1 600 mm to 800 mm . The results are of great significance for studying the mechanism of detonation noise and expediting the process of the engineering application.