直升机旋翼干扰对尾桨气动噪声影响的数值研究

Numerical Research on Aeroacoustic Characteristics of Helicopter Tail⁃Rotor Under Rotor Interaction

采用基于运动嵌套网格的CFD方法来模拟直升机旋翼/尾桨气动干扰流场,为旋翼/尾桨干扰噪声的计算提供准确的非定常气动力,并采用FW-H方程来计算干扰状态下的尾桨气动噪声。采用建立的计算模型,针对不同飞行状态下的尾桨噪声特性进行数值模拟,分析了旋翼尾流对尾桨气动噪声的干扰特性,并着重研究了尾桨重要的设计参数——旋转方向和垂向位置对尾桨噪声的影响规律。计算结果表明:悬停时,旋翼对尾桨的气动干扰影响会导致尾桨的噪声水平有所增加,但不会发生显著的变化;前飞时,旋翼干扰对尾桨噪声影响较大,且旋转方向和垂向位置对干扰噪声特性具有重要影响。

Firstly,a calculation model is established for aeroacoustic analysis of main-rotor/tail-rotor interaction.In the established calculation model,a CFD model based on the motional embedded grid system is adopted to simulate the aerodynamic interaction flow-field of helicopter main-rotor/tail-rotor configuration,and FW-H equations are used to calculate the interaction noise of tail-rotor.Secondly,based on the developed calculation model,the tail-rotor noise characteristics under the main-rotor interaction in different flight conditions are calculated in detail,and the influence of the rotor wake on the tail-rotor noise is analyzed.In addition,the influence of design parameters of tail-rotor(i.e.rotation direction and vertical position relative to the rotor plane)on the tail-rotor noise is studied seriously.The calculation results indicate that in hover,the noise level of tail rotor increase slightly due to the interaction of main rotor wake,but no significant changes of noise occur.At forward flight,the noise level of tail rotor is influenced by the main rotor wake obviously,and rotation direction and vertical position of the tail-rotor have important influence on the acoustic characteristics of tail rotor.