凸肩径向位置对风扇叶片振动特性的影响

针对带凸肩风扇叶片的动力学设计需求,研究凸肩径向位置对风扇叶片振动特性的影响规律.基于梁理论建立带凸肩风扇叶片的力学模型,采用瑞利法推导了1阶固有频率解析解,并获得了1阶固有频率随凸肩径向位置的变化规律.基于非线性接触有限元法,研究了凸肩径向位置对接触状态和振动特性的影响.研究结果表明:凸肩径向相对位置为0.75时,可使叶片具有最大的刚度值和1阶固有频率值.而综合考虑多阶模态频率时,凸肩径向相对位置为0.55至0.68时,叶片振动特性最优.凸肩接触正压力随凸肩径向位置增加而下降,切向接触刚度随凸肩径向位置的增加先增加后减小. 

Influence of the shroud's radial position on vibration characteristics of the fan blade

The influence of the shroud's radial position on the vibration characteristics of the fan blade considering its dynamics design requirements was investigated. Mechanical model of the shrouded fan blade was built based on beam theory, and the first order natural frequency was obtained using Rayleigh method. Further the influence of the shroud's radial position on the first order natural frequency was also acquired. The influence of the shroud's radial position on the contact status and vibration characteristics was also investigated by the nonlinear finite element method with contact elements. The results reveal that the stiffness and the first order natural frequency are maximal while the relative shroud's radial position is 0.75. The vibration characteristics for multi-modes are best while the relative shroud's radial position is 0.55-0.68. The pressure of the contact surface of the shroud decreases for the increasing of the relative shroud's radial position, and the tangential contact stiffness first increases and then decreases for the increasing of the shroud's radial position.