基于气动噪声监测的倾转旋翼涡环状态规避方法研究

Compared with conventional single-rotor helicopters, tilt rotor is more susceptible to dangerous Vortex Ring State (VRS) due to its unique configuration when operating in descent and maneuvering flight. Rotor thrust and control loss in VRS make it difficult to get out of this state. Early warning in VRS is an effective way to avoid crash and improve safety performance. At present, there is no feasible early warning method for VRS at home and abroad. The aim of this project is to establish a robust and high resolution method for simulating the aerodynamic characteristics of tilt rotor, and to achieve the following objectives: 1. To reveal the evolution mechanism of tilt rotor flow field in VRS, and clarify its relationship with the sudden loss of rotor performance by CFD/vortex particle coupling method; 2. To analyze the influence of different tilt rotor blade shape parameters on VRS, and seek the well-designed blade shape; 3. To find out the acoustic radiation characteristics in VRS of tilt rotor, and explore the strategy of automatic identification and avoidance method of VRS from the noise spectrum characteristics. Through the research of this project, the aerodynamic and acoustic characteristics of tilt rotor VRS can be mastered, which provides a scientific basis for the development of the monitoring equipment for tilt rotor VRS.

相对常规的单旋翼直升机而言，倾转旋翼由于其独特的构型特征，在进行下降、机动等飞行时更容易进入危险的涡环状态。进入深度涡环状态后，旋翼拉力急剧损失、操纵严重失效使得改出极为困难。在涡环状态的早期及时发出预警，是避免出现坠机事故、提升安全性能的有效方式。然而目前，国内外尚缺乏切实可行的涡环状态早期预警方法。本项目旨在建立一套鲁棒性强、模拟精度高的倾转旋翼涡环状态数值计算方法，达到如下目标：1. 通过CFD/涡粒子耦合数值模拟揭示倾转旋翼涡环状态流场演化机理，阐明其与旋翼性能突变的关系； 2.分析不同倾转旋翼桨叶外形参数对涡环状态的影响机制，寻求良好的倾转旋翼桨叶外形设计方案；3.摸清倾转旋翼涡环状态的气动噪声辐射特性，探索从噪声频谱特征辨识涡环状态并提出规避策略。通过本项目的研究，可以掌握倾转旋翼涡环状态的气动及噪声特性，为我国后期开展倾转旋翼机以及涡环状态监测和预警设备的研制提供科学基础。

相对常规的单旋翼直升机而言，倾转旋翼由于其独特的构型特征，在进行下降、机动等飞行时更容易进入危险的涡环状态。在国家自然科学基金青年科学基金项目“基于气动噪声监测的倾转旋翼涡环状态规避方法研究”（编号1190020949）的支持下，课题组建立了一套鲁棒性强、高精度的CFD/涡粒子耦合数值模拟方法，计算效率相对传统CFD方法提升了50%以上。应用这套耦合方法揭示了旋翼涡环状态流场演化与旋翼性能突变的关系。通过倾转旋翼下降和涡环状态的数值模拟，揭示了倾转旋翼流场演化特征和气动噪声辐射特性，提出了基于气动噪声监测的倾转旋翼涡环状态规避方法。依托课题研究内容，共在国内外学术期刊或会议上发表论文4篇（其中SCI检索1篇、EI和核心论文1篇）、申请专利2项。