基于CFD/CSD耦合的大型风力机非线性气动弹性计算方法

CFD/CSD based numerical method of nonlinear aeroealsticity for large-scale wind turbines is studied in this project. A point matched sliding grid strategy is designed out to improve the accuracy and efficiency of DES simulation for large wind turbines. An efficient and roubust TFI-RBFs hybrid dynamic grid technique is developed for dynamic grid generation of complex multi-block structured grid ,which is a urgent problem to be solved for current CFD study. For the first time, the dynamic linearization method is employed to the geometrical nonlinear aeroelasticity of large wind turbine blades, and an integrated method with an effective CFD/CSD model is established for the static and dynamic aeroealstic problems with geometrical nonlinearity. For the rigid-flexible multibody system of large wind turbine, the flexible multibody dynamics method is applied to analyze its dynamic coupling behaviors. By considering aerodynamic and structural nonlinearities simultaneously, an innovative time-domain CFD/CSD model is achieved for large wind turbines, which can enable an accurate analysis for aeroealstic prolem with aerodynamic nonlinearity, geometrical nonlinearity and dynamic coupling effects. The research results of this project can provide an advanced numerical method for the nonlinear aeroealstic analysis and lay a technique foundation for an integrated aerodynamic/structural design for large-scale wind turbines.

本项目针对大型海陆风力机气动弹性这一关键问题，开展基于CFD/CSD耦合的非线性气动弹性计算方法研究。提出点对接滑移网格策略用于大型风力机绕流DES高精度数值模拟；发展出TFI-RBFs混合的高效动态网格技术，有效解决CFD领域急需解决的复杂分块结构网格的动网格问题。首次将动力学线化方法应用于大型风力机叶片几何非线性问题，建立起CFD/CSD耦合的叶片几何非线性静、动气动弹性一体化高效计算方法。应用柔性多体动力学分析大型风力机的动力学耦合效应。突破气动非线性-结构非线性直接耦合计算的瓶颈，创新性的建立起同时考虑气动非线性、叶片几何非线性和动力学耦合效应的大型风力机气动弹性CFD/CSD时域耦合计算方法。本项目研究能为大型风力机气动弹性分析和气动-结构一体化设计提供先进的数值方法和技术支持，既有理论研究意义也有工程应用前景。

非线性气动弹性是大型海陆风力机研制过程中的关键科学问题。本项目研究大型风力机非线性气动、非线性结构及其CFD/CSD耦合计算方法。发展出适于复杂多块结构动态网格生成的无限插值-径向基函数（TFI-RBFs）等多种混合方法，结合点对接滑移网格策略，有效解决风力机气动弹性CFD计算的动网格问题。发现离散几何守恒律(DGCL)在风轮旋转过程中的误差累积现象，提出一种消除该误差的DGCL。建立起基于脱体涡模拟（DES）的风力机绕流N-S方程精确计算方法。同时发展出考虑结构影响的自由涡尾迹方法(FVW)，实现风力机气动力的快速计算。采用增量有限元方法建立几何非线性结构动力学方程，结合气动-结构数据传递的多点约束（MPC）方法，建立起几何非线性静弹CFD（FVW）/Nastran耦合迭代计算方法。基于叶片静平衡构型进行动力学线化，发展出几何非线性动弹CFD（FVW）/CSD时域耦合计算方法。考虑动力学耦合效应，建立起整机刚-柔混合多体动力学（MBD）算法和CFD（FVW）/MBD时域耦合计算方法。本项目研究成果突破了风力机气动非线性-结构非线性直接耦合计算的瓶颈，为大型风力机非线性气动弹性分析提供了先进的数值方法，并已拓展至包括发动机叶片在内的飞行器气动弹性计算分析。