旋转锯片空气动力学噪声特性计算与分析

为分析旋转刀具在气流作用下的声学特性，基于多场耦合计算方程建立了流场-结构-声场联合仿真模型，通过弹性体与流场的动力学计算得到了结构强迫振动响应，利用边界元法将振动响应信息作为声学边界，获取了锯片的声场辐射信息，噪声预估值与实测结果吻合良好。研究了锯片旋转过程中周围流场媒介的层流、湍流特性对锯片振动的影响规律；揭示了流-固耦合作用对声场时域、频域影响作用机制；确定了锯片空载噪声辐射的方向特性；分析了锯片尺寸结构对噪声的影响规律，为低噪声锯片的设计提供了参考依据。

Calculations and Analyseis on Aerodynamic Noise Characteristics of Rotating Saw Blades

In order to analyze the acoustic characteristics of the rotary tool under the fluid action, a combined simulation model was constructed based on coupled-field calculation equations. Firstly, the vibration response characteristics of the structure were extracted under the system which contained the rotating saw blades and air flow.Moreover, the vibration responses were regarded as acoustic boundary conditions to calculate acoustic radiation of the circular saw based on the boundary element method.Then, a structure acoustic coupling model was established to calculate the sound pressures. As compared with the experimental results, the coupling model may be used to noise prediction of the rotary tool.The laminar flow may turbulent flow characteristics of blade vibrations were studied in the processes of the rotating saw with around flow field and the sound radiation in time domain characteristics and laminar and turbulent characteristics with the coupled system was studied herein. Then,the characteristics of the directivity of aeroacoustic noise were studied. Finally，the influences of the size structure on the noise of the saw was determined, which provides a method for desining a low noise circular saw.