摘要
为了在气流当中进行噪声测量,传声器上必须加装适当形式的鼻锥以降低传感器自噪声。否则,传感器自噪声会过大而影响正常的声学测量。所以,当在高速气流中进行声学测量时,传感器自噪声成为测量的制约因素。如何降低传感器自噪声成为高速气流中声学测量的关键。鼻锥的形式对传感器自噪声有重要的影响。为了发展低噪声鼻锥,采用实验的方法,在闭口风洞声学实验段中,研究了两种形式鼻锥在风速为10m/s～50m/s时的声学特性。实验结果表明,半球型头部的鼻锥在风速为30m/s～50m/s时比常见的鼻锥自噪声小约3～11(dB)。因此,使用半球型头部的鼻锥可以改善测试条件或提高实验风速。
Flow-induced tones will be generated in the case where the microphone mounted in high-speed flow. The SPL （Sound Pressure Lever） of flow-induced tones limits the required flow speed of aero-acoustic experiment. A nose cone, which plays an important role, must be jacketed the microphone for reducing flow-induced tones. In order to reduce SPL of flow-induced tones as much as possible, an experiment was conducted to investigate the characteristics of flow-induced tones of two different nose cones. The two nose cones, one is usual nose cone having a taper head and the other is one having hemisphere head with screen covered, were tested in NF-3 wind tunnel of North-Western Politechnical University, and the test section is octal with 2.2m wide every side. When the flow speed are 10m/s and 20m/s, the SPL and power-spectrum of flow-induced tones of the two nose cones are similar. When the speed reaches 30m/s, 40m/s and 50m/s, their power- spectrum are still similar, but the nose cone with hemisphere head and screen, comparing with the usual one, can reduce the SPL of flow-induced tones by 3-11 （dB）. The results show that the nose cone with hemisphere head and screen is better than the usual one in aero-acoustic experiment when the sensor mounted in high-speed flow.
出处
《声学技术》
CSCD
北大核心
2007年第1期96-100,共5页
Technical Acoustics
基金
西北工业大学"英才计划"项目
关键词
气动声学
高速气流
传感器自噪声
鼻锥
风洞实验
aero-acoustics experiment
high-speed flow
flow-induced tones
nose cone
wind tunnel
