ZJ-200-25型螺旋离心泵转子静力学分析

为研究螺旋离心泵叶轮与转轴工作时的振动特性,以ZJ-200-25型双叶片螺旋离心泵为研究对象,建立了螺旋离心泵内部流场三维模型,并对其设计工况进行了数值模拟.建立转子部分的有限元模型,根据泵腔内流场压力分布,对转子进行了有预应力的静力学分析和模态分析,获得了转子的对载荷的响应信息、固有频率和对应的振型.结果表明：转子强度满足设计要求,应力最大的点位于叶片根部及轴肩处;转子为刚性,但其在工作时的叶片通过频率与前两阶固有频率比较接近,这说明转子的转速不尽合理,工作时产生共振的可能性较高.因此需要对螺旋离心泵转子结构进行优化设计,可通过更改轴承位置、重新设计轴向和径向尺寸以及更换轴的材料来实现.从而改变转子的固有频率,使固有频率能够避开泵内流动的激励频率,避免发生共振.

Static analysis on rotor of type ZJ- 200 -25 screw centrifugal pump

In order to investigate the vibration characteristics of impeller and pump shaft of screw centrifugal pump in operation, the type ZJ -200 -25 screw centrifugal pump with double blade was chosen as the study model. A three-dimensional mathematical model of fluid flow in the pump was estab-lished and the flow was simulated numerically under the design condition. A finite element model for the rotor system of the pump was generated as well. The statics and mode analysis were conducted un- der the flow field pressure distribution in pump chambers when the rotor was pre-stressed. The 1 st to 6th order natural frequencies and the modes of vibration of the rotor system were obtained. It was showed that the strength of the rotor completely satisfies the design requirement and the maximum stress points were located at the root of blades and the shoulder of shaft. The rotor was rigid, and a natural frequency of rotor system was close to the blade passing frequency of impeller, thus the rotor system design was unreasonable. Therefore, it is necessary to optimize the structure of rotor by altering the position of bearings, resizing shaft diameter and changing material. In that cases, the natural frequency of the rotor will be ehanged and may be far away from the blade passing frequency.