喷管尺寸对超声速喷流噪声影响研究

摘要

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.%To investigate the characteristics of supersonic jet noise and the impact of nozzle size on the acoustic distribution,a cold jet experimental system was designed in this paper. The jet noise from different size of nozzle and in different flow pressure was measured by the LMS data acquisition system and analyzed by the noise processing software. Experiment results show that the supersonic jet noise has a strong directionality,with the measuring point deviating from the central axis of the jet from 30° to 180°,the peak of the sound pressure level decreases, and the peak frequency changes little. With the increase of nozzle size, the sound pressure level increases,and the peak frequency decreases. Under this experiment conditions,the sound pressure level distributes at the bounds of 80 ~ 120 dB,and the peak frequency increases from less than 6 000 Hz to more than 11 000 Hz when the throat diameter of the nozzle decreases from 10 mm to 5 mm.