某轿车车内气动噪声特性的试验研究

An Experimental Study on the Interior Aerodynamic Noise Characteristics of a Sedan

在分析了轿车车内气动噪声产生机理和传递路径的基础上,进行了整车气动声学风洞试验。首先调查了车内气动噪声的频谱特征和空间分布规律,其次对车内噪声的速度特性和偏航角度的影响进行了研究,最后对整车密封和后视镜对车内噪声的贡献进行了分析。结果表明:偏航角为0°时,人工头外耳的声压级几乎在整个频段都比内耳的声压级高,车内总声压级的分布基本上对试验车的纵对称面左右对称。不同风速下车内气动噪声的频谱特征很相似,车内噪声的线性总声压级和A计权总声压级随风速变化的特征指数分别为4.3和5.4。车内风噪水平随偏航角度的增加而增大,同样的偏航角下,背风面的风噪水平通常比迎风面高。在500Hz-2k Hz频段,车内噪声对偏航角的变化最敏感。另外,密封件在500Hz-4k Hz的中高频段对车内噪声的贡献较大,而后视镜只在4-7k Hz的高频段才显出其对车内噪声的贡献。

Based on an analysis on the generation mechanism and transmission path of interior aerodynamic noise, an aeroacoustic wind tunnel test is conducted on a sedan. Firstly the spectra characteristics and spatial distri- bution rule of interior aerodynamic noise are investigated. Then the sound pressure spectrum under different wind speeds and yaw angles are studied. Finally the contributions of sealing parts and rear view mirror to interior noise are analyzed. The results show that with a zero yaw angle, the sound pressure level at artificial outer ear is higher than that in inner ear in almost whole frequency range and the distribution of overall interior sound pressure level is basically symmetrical about the longitudinal symmetric plane of vehicle. The sound pressure spectra of interior aero- dynamic noise at different wind speeds are rather similar and the characteristic exponents of linear and A weighted o- verall sound pressure levels of interior noise are 4. 3 and 5.4 respectively with respect to the change of wind speed. The interior aerodynamic noise goes up with the increase of yaw angle, and under the same yaw angle, the noise lev- el by leeward side is normally higher than that by windward side. In the frequency range of 500Hz-2kHz, interior noise level is most sensitive to the variation of yaw angle. In addition, the sealing parts have more contributions to interior noise in the frequency range of 500Hz-4kHz, while for rear view mirror, its contribution becomes noticeable only in the high frequency range of 4-7kHz.