中文摘要：

将Lighthill方程转化为变分形式，考虑声传播在复杂固壁内的反射，折射等，利用有限元方法对某汽车空调系统离心风机气动噪声进行了数值计算．也采用积分方法对其气动噪声进行了计算，此方法采用自由空间格林函数，在求解远场声辐射问题时将其简化为自由空间问题．首先建立离心风机CFD计算网格，通过离散涡模拟计算了离心风机内部非定常流动，通过涡量云图、声功率云图及各处的压力波动曲线分析出主要噪声源为叶片压力面及蜗舌前后部；然后建立气动声学有限元计算模型，分为考虑蜗壳和不考虑蜗壳的情况，计算离心风机辐射噪声．有限元计算结果与积分法计算结果的对比表明：用格林函数的积分解法进行计算时，其所做的简化导致结果产生较大误差，气动声学的有限元计算方法与实际吻合较好．

英文摘要：

Transforming the Lighthill equation into a variational form, the aerodynamic noise of centrifugal fan of HVAC in automobile was numerically calculated by finite element method with the consideration of the reflection and refraction of sound transmission in complex solid surfaces. Simplifying the free space Green function as a free space problem for far field sound radiation, the aerodynamic noise was also calculated by integration method. The unsteady flow inside centrifugal fan was calculated by DES model to show that the major noise sources were from blade pressure surfaces and the fl＇ont and rear parts of tongue according to the analyses of the contours of vorticity, sound power and pressure fluctuation at different lo- cations. Two aeroacoustic finite element models were established to calculate the radiating noise of cen- trifugal fan with and without consideration of volute. The comparison results show that the aeroacoustic calculation results based on finite element method have good consistency with reality, while the simplification of integral solution by Green function results in large error.