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为了考虑叶轮机叶片结构与流体之间的耦合效应,同时提高叶轮机颤振数值研究的效率,发展了一种基于非定常气动力降阶模型(ROM)的叶栅耦合颤振分析方法。该方法运用时域计算流体力学(CFD)技术计算少数几个叶片的非定常气动力,通过系统辨识及一些假设构建整个叶栅振动的非定常气动力降阶模型,并在状态空间耦合叶栅结构动力学方程建立叶栅气动弹性方程,采用特征值和时域仿真分析该系统稳定性。运用该降阶耦合方法对STCF4(Standard Test Configuration 4)以及NASA Rotor67叶栅系统的稳定性进行了计算。通过与直接计算流体力学/计算结构动力学(CFD/CSD)耦合方法和非耦合方法计算结果的比较验证了该方法的准确性,且该降价耦合方法的计算效率相对于直接CFD/CSD耦合方法提高了1~2个量级,为叶轮机气动弹性参数研究、失谐研究以及多模态耦合计算等提供了便利。
In order to consider the coupling effect between blade structure and fluid, and to improve the efficiency of numerical research on impeller flutter, a cascade flutter analysis method based on unsteady aerodynamic order reduction model (ROM) is developed. The method calculates the unsteady aerodynamic forces of a few blades by using the time-domain Computational Fluid Dynamics (CFD) technique. Through the system identification and some assumptions, the unsteady aerodynamic force reduction model of the whole cascade vibration is constructed. In the state space coupled cascade The dynamic equation of the structure is used to build the cascade aeroelasticity equation. The stability of the system is analyzed by eigenvalue and time domain simulation. The stability of STCF4 (Standard Test Configuration 4) and NASA Rotor67 cascades system is calculated by using the reduced-order coupling method. The accuracy of this method is verified by comparison with the CFD / CSD and non-coupling methods. Compared with the direct CFD / CSD method It improves the aeroelastic parameters of impeller, studies on detuning and multi-modal coupling calculation.