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为研究喷管尺寸对超声速喷流噪声特性的影响及其声场分布规律而设计了冷流实验系统,选用3种不同尺寸的喷管,采用LMS数据采集系统及噪声处理软件,对不同喷管尺寸、不同来流压强下的喷流噪声进行了采集和处理。实验结果表明,超声速喷流噪声具有较强的指向性,随着测点偏离喷流中心轴线角度从30°增加到180°,其声压级峰值逐渐减小,峰值频率变化不大;随着喷管尺寸的增大,声压级逐渐增大,其峰值频率逐渐减小;在该实验工况下,声压级峰值分布在80～120 dB,随着喷管尺寸从喉径10 mm降低到5 mm,峰值频率从不到6 000 Hz提高到11 000 Hz以上。
In order to study the influence of nozzle size on the noise characteristics of supersonic jet flow and its sound field distribution, a cold flow experimental system was designed. Three different nozzle sizes were selected. LMS data acquisition system and noise processing software were used to measure the nozzle size , Different flow pressure jet flow noise were collected and processed. The experimental results show that the noise of supersonic jet has a strong directivity. As the measuring point deviates from the central axis of the jet from 30 ° to 180 °, its peak value of sound pressure decreases and its peak frequency does not change much. With the increase of nozzle size, the sound pressure level gradually increases and the peak frequency decreases. Under this experimental condition, the peak value of sound pressure level is distributed between 80 and 120 dB. As the nozzle size decreases from the throat diameter of 10 mm To 5 mm, the peak frequency increased from less than 6 000 Hz to over 11 000 Hz.