脉冲爆震发动机微穿孔消声喷管研究

针对脉冲爆震发动机的噪声辐射特性，计算分析微穿孔板孔径、板厚、穿孔率、前后腔厚度等设计参数对单／双层微穿孔板吸声体共振频率、吸声系数的影响。设计并加工一组微穿孔消声喷管。实验研究发现：影双层微穿孔消声喷管对脉冲爆震发动机噪声辐射的降低都有一定的作用，双层结构优于单层结构；消声喷管越长，消声效果越好；发动机工作频率为20Hz时，300mm长双层微穿孔消声喷管可使噪声辐射峰值声压级降低2dB左右，脉冲声压级和声功率级降低4dB左右，声功率从1377．2W下降至542W。

Investigation on Noise Elimination Nozzle with Micro-Perforated Panel in Pulse Detonation Engine

Aiming at the noise radiation characteristics of a pulse detonation engine （PDE）, the effects of hole diameter of micro-perforated panel, panel thickness, perforation ratio, and front/back cavity depths on absorber＇s resonance frequency and sound absorption coefficient of single/double micro-perforated panel are calculated and analyzed. A set of noise elimination nozzles with micro-perforated panel is designed and fabricated. In experimental investigation, it is found that both of single and double micro-perforated panels of noise elimination nozzle（SMPN/DMPN） the effect in decreasing the noise radiation level of PDE, DMPN is better than SMPN, and noise elimination effect can be much better when muffler＇ s length increases. When the PDE is operating at 20Hz frequency, a 300mm long DMPN can bring about 2dB decrease for the peak sound pressure level, 4dB decrease for the impulse sound pressure level and sound power level, and a decrease from 1377.2W to 542W for sound power.