相位延迟边界条件在叶轮机械颤振分析中的应用

基于带相位延迟的周期边界条件,建立了某跨声速转子的双通道高效气动阻尼计算模型.数值计算了该转子的气动性能、颤振边界和叶片模态,和实验数据吻合较好.通过传统的多通道能量法以及双通道方法计算了叶片在一弯模态,不同叶片间相位角条件下的气动阻尼,获得了基本一致的计算结果,而双通道方法相比于传统的多通道能量法计算效率提升约7.7倍,内存需求约为后者的0.45倍.不同叶片振幅对气动阻尼结果的影响研究表明,对于较小的叶片振幅,流动非线性对气动阻尼计算结果仍然有显著的影响.不同工况的计算结果表明:叶片间相位角对转子叶片的气动阻尼有显著的影响,对于该转子最小的气动阻尼均在叶片间相位角为-42.4°时得到;同时,在近颤振状态,不同叶片间相位角对应的气动阻尼均小于近设计状态.

Flutter analysis of turbomachinery based on phase lagged boundary condition

Based on phased lagged boundary conditions, an efficient aerodynamic damping computational model of a transonic compressor rotor with double passage was established. Numerical results of rotor aerodynamic performance, flutter boundary and blade modal analysis were consistent closely with experimental results respectively. The aerodynamic damping results of rotor with different interblade phase angles (IBPA) and first bending mode were calculated using double passage method and conventional multiple passage energy method. The numerical results indicated that the aerodynamic damping attained by double passage method and conventional multiple passage energy method agreed with each other. The efficiency was improved by almost 7.7 times than conventional multiple passage energy method and the memory requirement was about 0.45 times to the conventional method. The aerodynamic damping results for different vibration amplitudes demonstrates that the nonlinear fluid dynamics effects are significant at such a small geometric displacement. Compared with the damping at design point, aerodynamic damping of rotor is reduced at near flutter operation condition, while the minimum aerodynamic damping is gotten at the same interblade phase angle (-42.4 degree).The results show that IBPA has significant influence on the flutter of rotor blades.