叶轮偏心引起的气流激振力对转子稳定性影响的分析

 转子偏心引起的气流激振力在一定条件下可能诱发转子失稳。分析了叶轮偏心引起转子失稳的机理和特点。以Jeffcott转子为例,利用Routh-Hurwitz准则讨论了叶轮偏心转子失稳的影响因素。研究表明支承刚度的不对称和大阻尼比都将提高转子稳定性的门槛值。提出了叶轮偏心转子失稳门槛值的计算方法,建立了优化模型,通过优化转子系统的支承刚度和直径提高了系统的失稳门槛值。计算实例表明了该方法对提高系统的稳定性具有良好的效果。

Stability Analysis of Rotor Systems with Gas Exciting Force Caused by Blade Tip Clearance

The gas exciting force caused by blade tip clearance may cause rotors unsteady under certain condition. The theory and the characteristics of the force caused by the blade tip clearance are analyzed. Taking the Jeffcott rotor as an example, the influence factors of rotor system with gas exciting force caused by blade tip clearance are discussed through Routh-Hurwitz rule. It is found that the asymmetric stiffness and large damping ratio will both enhance the threshold of stability. A method that can be used to calculate the threshold of instability is put forward and an optimized model is set up in the paper. Threshold of the instability is improved by optimizing bearing stiffness and diameter of rotor system. It is indicated that this method has good results in improving systematic stability by an example.