短舱耐温声衬声学试验系统设计与试验研究

Acoustic Test System Design and Experimental Research for Nacelle Temperature Resistant Acoustic Liner

关键词:  短舱  耐温声衬  声学试验  切向流  温度梯度

Key words:  Nacelle  Temperature-resistant acoustic liner  Acoustic test  Grazing flow  Temperature gradient

摘要:

为了研究耐温声衬的声学特性，针对发动机短舱耐温声衬的应用环境，设计并研发了能够基本模拟风扇噪声、切向流和高温等典型工况特征的耐温声衬声学性能试验系统，设计频率为0.5~16kHz，最大声压级为140dB，最大周向模态为10阶，最大切向流速度为0.7Ma，最高背板加热温度为200℃。提出了耐温声衬声学性能试验方法，对钛合金环形耐温声衬开展了声学试验，验证了试验系统并获得了背板加热和切向流对声衬降噪特性的影响规律，研究结果表明：声衬背板加热和声衬表面切向流都会导致耐温声衬降噪性能衰减，当背板温升至200℃时，降噪量降低7.5dB，当切向流速度增加至0.3Ma时，降噪量衰减13.7dB。

Abstract:

In order to study the acoustic characteristics of temperature resistant acoustic liner， according to the application environment of engine nacelle temperature-resistant acoustic liner， an acoustic performance test system for heat-resistant acoustic liner is designed and manufactured， which can basically simulate the typical working conditions such as fan noise， grazing flow and high temperature. The fan sound source with frequency range of 0.5~16kHz， maximum sound pressure level of 140dB and maximum circumferential mode of 10 orders was designed. The maximum grazing flow velocity can be 0.7Ma and the maximum heating temperature of the backplate can be 200℃. The acoustic performance test method of temperature-resistant acoustic liner was proposed. The acoustic test of titanium alloy ring temperature-resistant acoustic liner was carried out. The test system was verified and the influence of back heating and grazing flow on noise reduction characteristics of acoustic liner was obtained. The results show that the heating of the acoustic liner backplate and the grazing flow of the acoustic liner surface led to the attenuation of the noise reduction performance of the temperature-resistant acoustic liner. When the backplate temperature rose to 200℃， the noise reduction was decreased by 7.5dB. When the grazing flow velocity increased to 0.3Ma， and the noise reduction was decreased by 13.7dB.