一种高效的叶轮机叶片气动阻尼计算方法

AN EFFICIENT METHOD ON AERODYNAMIC DAMPING COEFFICIENT CALCULATION FOR TURBOMACHINERY

运用叠加原理,发展了一种可以运用于小振幅运动的叶轮机叶片非定常气动力降阶模型,并将该模型与传统的能量法相结合,提出了一种叶轮机叶片气动阻尼的高效求解方法.运用该方法求解叶轮机叶片的气动阻尼系数,对某个频率、某个模态只需要进行一次非定常计算,就可以求出所有叶间振动相角下的气动阻尼系数,提高了气动阻尼的求解效率.在STCF4和NASA Rotor 67两个算例上运用非定常雷诺平均N-S(RANS)方程和提出的降阶模型进行了对比计算.算例表明,在小振幅下该方法的计算结果与RANS方程计算得到的气动阻尼系数能很好地吻合,而计算效率相比多通道非定常RANS方程计算提升了近一个数量级,并且该方法还可以运用于有失谐情况的颤振分析,在工程上有较高的应用价值.

It is always difficult to perform aeroelastic analysis on turbomachinery efficiently and precisely due to the complexity of the flow field and structures. The authors develop an unsteady aerodynamic Reduced- Order-Model （ROM） which can be used on small amplitude vibrating blades of turbomachinery. Based on this ROM and classic energy method, an efficient method on aerodynamic damping coefficient calculation for turbomachinery is introduced. With this method, only one unsteady CFD computation is needed to calculate the aerodynamic damping coefficients at all Inter Blade Phase Angles （IBPA） under one specific modal and frequency. The aeroelastic characteristics of STCF4 and NASA Rotor 67 are analyzed by using this ROM with classic energy method. The numerical results indicate that the aerodynamic damping coefficients attained by ROM and unsteady RANS method agree well with each other in the condition of small amplitude of vibration. The efficiency is improved by almost 10 times than multi-passages RANS method. In addition, this ROM can be used in aeroelastic analysis with mistuning effects.