叶轮机湍流噪声的声源分布机理和辐射传播特性研究与湍流力学、涡声理论相互交织，其非线性特征严重影响涡扇发动机的进一步降噪设计。本项目以单级轴流风扇为对象，提出叶轮机湍流噪声的声源成像新方法。研究内容包括：采用旋转声源模拟仿真和涵道风扇声学实验，分离识别不同气动噪声源的方位和声辐射特征，探索叶轮机湍流噪声的声源分布机理；建立声模态识别误差传递函数，优化设计传声器阵列，探明声模态频谱特征和声场能量分布规律；揭示管道声模态主瓣辐射角与远场指向性的依赖特性，构建湍流噪声辐射指向性预测模型，提出远场辐射声压与声源分布之间的数学函数。本项目旨在探明气流管道湍流噪声的声源分布机理和建立辐射指向性预测模型，提出适用于管道内宽频噪声的声源成像新方法和声模态识别方法，建立和发展叶轮机湍流噪声正/反问题研究方法的基本理论，为航空发动机湍流噪声的声源定点降噪和指向性定向控制提供参考。

The research on the sound source distribution mechanism and radiation characteristics of turbulent noise in turbomachinery is intertwined with turbulence mechanics and vortex sound theory, and its nonlinear characteristics seriously affect the further noise reduction design of turbofan engine. In this project, the single-stage axial-flow fan is taken as the object and a new source imaging method for turbine turbulent noise is proposed. The research contents include: using the simulation of rotating noise source and the acoustic experiment of ducted fan to separate and identify the position and acoustic radiation characteristics of different aerodynamic noise sources, to explore the distribution mechanism of turbulent noise sources of turbine; to establish the error transfer function of acoustic mode identification, to optimize the design of microphone array, to explore the characteristics of acoustic mode spectrum and the distribution law of sound field energy; to reveal the dependency characteristics between the ducted mode main-lobe radiation angle and far-field directivity, to construct a prediction model of the radiation directivity of turbulent noise and puts forward the mathematical function between the distribution of sound source and sound pressure in far-field radiation. The purpose of this project is to find out the distribution mechanism of the noise source in turbulent flow duct and to establish the prediction model of radiation directivity. A new sound source imaging method and a mode identification technique for ducted broadband noise are proposed. The basic theory of the research method for the positive / negative problems of the turbulent noise in turbomachinery is established and developed, which can provide a reference to the exact location noise reduction and directional radiation control for turbulence noise of aeroengine.