风力机叶片气固两相非定常流动特性研究

With the planning and construction of ten million kilowatt wind power base，the western area ushered in the golden period of the development of wind power, however,GanSu,XinJiang,Inner Mongolia and other regions exist frequent dust weather make the wind machine often run in the gas-solid two-phase flow. This topic is based on northwest sandy wind conditions,through theoretical analysis and numerical methods to study the influence of sand on the airfiol aerodynamic performance and flow structure , establish wind turbines gas-solid two phase flow model , reveal the gas-solid two phase flow characteristics of wind turbines and unsteady aerodynamic forces , and propose aerodynamic measures to control aerodynamic instability. PIV and the surface fluctuating pressure measurement technique are used to measure velocity field and pressure distribution of the blade in the wind tunnel，extract the impact of sand on flow field structure and aerodynamic characteristics, to test the gas-solid two phase flow model and unsteady characteristics; Using 191 pressure sensors of outfield wind turbine blade, to measure pressure distribution in clean air and sandy air and compare their differences, unsteady aerodynamic performance and the impact of sand content are determined of the blade in the sandy environment. Finally, wind turbine blades are optimally designed, making it more suitable for the northwest wind conditions.

随着千万千瓦级风电基地的规划和建设，西部地区迎来了风电发展的黄金时期，然而甘肃、新疆、内蒙等地区频繁的沙尘天气，使风力机时常运行在气固两相流动中。本课题以西北沙尘来流风况为基础，首先应用理论推导和数值计算相结合的方法，研究悬移沙粒对翼型、叶片气动性能和流场结构的影响，建立风力机气固两相流动模型，揭示翼型的气固两相流动特性和气动力不稳定现象，并提出控制气动力不稳定的气动措施。其次利用外场专门研制的压力传感器，测定清洁空气与含沙空气中叶片的压力分布并比较差异，研究真实风沙环境中叶片的非定常特性和沙尘的影响；利用PIV和表面脉动压力测量技术，在风洞中测量叶片的速度场和压力分布，提取沙粒对流场结构和气动特性的影响，以检验气固两相流动模型和气动力非定常特性。最后优化设计风力机叶片，使其更适于西北多风沙环境。

随着千万千瓦级风电基地的规划和建设，我国西部地区迎来了风电发展的黄金时期，然而甘肃、新疆、内蒙等地区频繁的沙尘天气，使风力机时常运行在气固两相流动中。本课题首先基于N-S方程与离散相DPM模型耦合的数值计算方法，研究颗粒的入射方式从而确定了group入射类型。并以此为基础，研究气固两相流中圆柱的绕流特性，验证气固两相流动数值计算模型。其次，基于空气中所含沙尘悬移沙粒的物理特性，研究了翼型流场中沙尘颗粒的运行特性，不同直径颗粒、不同颗粒浓度及颗粒的重力效应对翼型气动性能的影响，以及气固两相中颗粒对翼型边界层转捩、分离等流场结构的影响，揭示了翼型的气固两相非定常演化机理及沙尘的绕流特性，提取了沙尘颗粒对流场结构和气动特性的影响规律。第三，分析了翼型及叶片的磨损规律，发现磨损出现在前缘且磨损与前缘半径有直接关系，而且可以采用临界Stokes数来判断翼型及叶片是否发生磨损。第四，开展外场实验，测量清洁空气和含固体颗粒时，风力机叶片表面压力分布特性和流场结构，以研究真实外场环境中风力机叶片的气动非定常特性，分析气动力对外场风特性的敏感性。最后，在多沙尘环境和清洁空气中开展兆瓦级风力机风轮的气动设计，将沙尘机组和清洁机组分别运行于清洁空气和含沙空气中，对比功率和推力特性，发现针对多风沙环境设计的风轮将大大提高风电机组的功率特性，而且会降低推力，这将有利于解决我国西北多沙尘环境中运行风力机的水土不服现象。