【作者】 张勇；

【导师】 王珑；

【作者基本信息】 南京航空航天大学 ， 机械， 2023， 硕士

【摘要】 风能作为世界能源市场中的重要组成部分,风力发电技术也是各国不断努力和发展的科技领域。风力机叶片作为风力机的核心部件,其设计对风力机的工作效率尤为关键。风力机的大型化作为风力机市场的发展趋势,传统的叶片优化设计基于BEM方法,然而BEM不考虑尾涡对叶片载荷的影响。因此本文建立了基于升力线自由涡尾迹模型的优化方法,对大型MW级水平轴风力机叶片进行气动优化设计,开展以下几方面的研究工作:首先,基于升力线自由涡尾迹模型(LLFVW)构建了风力机叶片气动性能分析方法,对NREL PhaseⅥ叶片进行气动力分析,并与叶片全尺寸模型风洞实验值进行对比。进一步对尾迹结构、定常气动载荷,低速轴扭矩进行分析,并与FAST、参考文献计算结果相对比,验证了LLFVW方法的准确性与可靠性,为后续的叶片设计提供气动计算基础。其次,基于LLFVW方法构建了一种风力机叶片环量优化设计方法。该方法通过迭代优化确定叶片附着涡环量的最佳分布,添加二阶导数保证环量分布光顺,环量的光顺保证了气动力的分布均匀,优化后的IEA 15 MW叶片相比原叶片具有更光顺的环量分布、C_p提高4.5%。最后,基于RANS方法对叶片进行数值仿真,验证了基于LLFVW方法的优化设计的可靠性。为了揭示增功机理,研究了优化叶片与原叶片的表面压力分布与截面压力分布特性。得出了优化叶片有较高的气动效率原因是:压力面前后缘压力较大,吸力面前缘压力变小,进而在前缘形成较大的压力差。结果表明r/R=0.3和r/R=0.5位置的压力系数积分值比原叶片更大。更多还原

【Abstract】 Wind energy is an important part of the world energy market and wind power technology is an area of science and technology that countries are constantly working on and developing.As the core component of a wind turbine,the design of the wind turbine blade is particularly critical to the efficiency of the wind turbine.As a trend in the wind turbine market,the traditional blade design optimization is based on the BEM method,however,the BEM does not take into account the influence of the wake vortex on the blade load.This paper therefore establishes an optimisation method based on the lift-line free vortex wake model for the aerodynamic optimisation of large MW-class horizontal axis wind turbine blades,carrying out research work in the following areas.Firstly,a wind turbine blade aerodynamic performance analysis method is constructed based on the lift line free vortex wake model(LLFVW),and the aerodynamic analysis of NREL Phase VI blade is carried out and compared with the experimental values in the wind tunnel of the full-scale blade model.Further analysis of the wake structure,constant aerodynamic loads,and low-speed shaft torque is carried out and compared with the calculation results of FAST and references to verify the accuracy and reliability of the LLFVW method and provide a basis for subsequent blade design aerodynamic calculations.Finally,the reliability of the optimised design based on the LLFVW method is verified by numerical simulation of the blade based on the RANS method.In order to reveal the mechanism of power gain,the surface pressure distribution and cross-sectional pressure distribution characteristics of the optimised blade and the original blade are investigated.It is concluded that the reason for the higher aerodynamic efficiency of the optimised blade is that the pressure at the trailing edge before the pressure is higher and the pressure at the leading edge before the suction becomes smaller,which in turn creates a larger pressure difference at the leading edge.The results show that the integral values of the pressure coefficients at r/R=0.3 and r/R=0.5 are greater than those of the original blade.更多还原