磁流变液阻尼器控制下贯流式机组轴系碰摩振动特性分析

针对贯流式水轮发电机组轴系受多振源引发的振动问题，基于线性接触力和库伦摩擦力组成的叶尖碰摩力模型，建立综合考虑不平衡磁拉力、油膜力以及不平衡水力等外激励影响下的机组转子–转轮–轴承系统碰摩动力学模型。为抑制转轮叶片振动诱发的碰摩故障，将一种电流调节式磁流变液阻尼器引入系统，采用数值方法研究有无磁流变液阻尼器在不同转速及转轮质量偏心下对转轮振动的抑制规律。结果表明：磁流变液阻尼器的存在使原本复杂的系统响应形式变得有序，能够减弱机组在转速变化过程中产生的振动，使转轮运动更为贴近同步周期运动形式；同时，可缩减因质量偏心变化造成的混沌行为并减小其振幅波动。磁流变液阻尼被动控制对贯流式水轮发电机组具有良好的适用性，可为贯流式机组轴系减振提供有益借鉴。

Analysis of Rub-impact Vibration Characteristics of Tubular Hydro-generator Set Shaft System Controlled by Magneto-rheological Fluid Damper

Aiming at vibration problem caused by multiple oscillation sources in the shaft system of tubular hydro-generator set,based on the model of tip impact force composed of linear contact force and Coulomb friction force,considering the external excitation of unbalanced magnetic pull,oil film force and unbalanced hydraulic force,etc.,the dynamic model of rotor-runner-bearing system with rub-impact was established.In order to suppress the rubbing fault stemming from vibration of runner blade,a current-regulated magneto-rheological fluid damper was introduced into the system,and the numerical simulation method was used to study the influence for both presence and absence of magneto-rheological fluid damper on inhibition law of runner vibration at different speeds and mass eccentricity of runners.The results show that the existence of magneto-rheological fluid damper makes the originally complex system response form become orderly,which can attenuate the vibration generated by units during the speed change process and make the runner movement closer to synchronous periodic motion form.Meanwhile,it can reduce the corresponding amplitude fluctuation and chaotic behavior caused by the change of mass eccentricity.Magneto-rheological fluid damping passive control has good applicability to the tubular hydro-generator set,which can provide a useful reference for shaft vibration reduction of tubular units.