Abstract: Numerical simulation of a threedimensional steady turbulent flow in the overall flow field, from the inlet of the collector to the outlet of the diffuser, of a counterrotating axialflow fan is performed. Unstructured grid is used to discrete the domain for computation. Pressure boundary conditions are specified to the inlet and the outlet. The SIMPLE algorithm in conjunction with the RNG kε turbulence model is used to solve the threedimensional NavierStokes equations. The moving reference frame is adopted to transfer data across the interface between the rotating field and the stationary field. The broadband noise source model based on the Lighthill noise analogy theory is introduced to simulate the aerodynamic noise field of the fan. The sound intensity distribution inside the fan, on the impellers, the blades and the shell of the fan are predicted. The pressure fluctuation of three interfaces around impellers caused by the rotating impellers and blades vibration is studied by the Fast Fourier Transform (FFT) method. The simulation results are of important significance to the optimal design and noise control of the fan.

Key words: acoustics, counterrotating axialflow fan, aerodynamic noise, noise source model, sound intensity level, pressure fluctuation, numerical prediction

摘要： 将SIMPLE算法与RNGε湍流模型相结合，通过求解NavvierStokes方程，对对旋风机从集流器进口到扩散器出口全流场内的三维定常流动进行数值计算。求解区域采用非结构化网格进行离散，以进、出口压力为边界条件，采用运动参考系实现动-静界面间的数据传递。对对旋风机气动噪声分布特性进行数值模拟，预测对旋风机内部、外壳和叶片的声强级分布情况。采用快速傅里叶变换方法（FFT）研究两级叶轮区域三对干涉面因叶轮旋转和叶片振动引起的压力变化规律。研究结果对通风机结构的优化设计及噪声控制具有参考意义。

关键词: 声学, 对旋风机, 气动噪声, 声源模型, 声强级, 数值预测