以实际压缩机组多跨转子系统为研究对象，针对由间隙气流激振力引起的失稳问题，进行Alford力作用下多跨转子系统的动力学及稳定性分析。针对该类模型自由度多的特点，采用固定界面模态综合法降维措施与Newmark-β法相结合，提高了求解效率。研究交叉刚度、工作转速等对转子涡动的影响，以及多跨转子系统中Alford力的传递作用；通过以时间历程曲线为稳定性判据，进行不同交叉刚度、阻尼、刚度系数下的稳定性分析。结果表明，交叉刚度的增大会加重转子涡动，降低系统的稳定性；系统阻尼和刚度的增大可提高稳定性；失稳交叉刚度与支承的交叉刚度存在一定关系，当其大于支承最小交叉刚度且接近支承最大交叉刚度时，系统容易失稳。
Abstract
Turbine rotor systems usually lose stability caused by Alford forces. Thus, dynamic characteristics and stability analysis of the multi-span rotor system of a practical compressor unit subjected to Alford forces were investigated. The Newmark-β method combined with the fixed interface Component Mode Synthesis (CMS) dimension reduction approach was applied to obtain the dynamic response due to much degrees of freedom of the large scale rotor system, and computational efficiency was improved obviously. The effects of cross stiffness, working speed on rotor whirling and the transmission acting of Alford forces on multi-span rotor system were investigated; taking the time-history curves as stability criterion, stability analysis with different parameters were discussed. It shows that rotor whirling will aggravate and stability decreases with increasing cross stiffness; stability is improved with the increase of damping and stiffness of system; while instability is apt to occur when the cross stiffness induced by Alford force is larger than the minimum cross stiffness of bearings and that is close to the maximum cross stiffness of bearings.
关键词
多跨转子 /
Alford力 /
交叉刚度 /
自激振动 /
稳定性分析
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Key words
multi-span rotor /
Alford force /
cross stiffness /
self-excited vibration /
stability analysis
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参考文献
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