多级离心泵临界转速及模型减缩分析

The Critical Speed and Model Reduction of a Centrifugal Pump

以多级离心泵转子为研究对象,采用商业软件分析了密封动力特性系数,并将密封动力特性系数考虑到湿态临界转速分析中。基于ANSYS软件建立了多级离心泵三维转子有限元模型,计算了干态和湿态情况下的临界转速。计算结果表明,考虑密封动力系数后湿态情况下,前3阶临界转速大于干态,第1阶临界转速为4 738 r/min,远大于工作转速2 980 r/min,临界转速满足设计要求。同时针对三维模型自由度多等特点,采用APDL程序对湿态下离心泵转子模型进行减缩,考虑了旋转陀螺效应和离心预紧力的影响。结果表明,模型自由度减缩了68%,临界转速最大误差为0.17%,稳态不平衡响应计算结果与原模型基本相同。

Taking a centrifugal pump rotor as a research object,the stiffness and damping of the centrifugal pump seal is done and used in “wet” critical speed analysis. 3D finite element model was made by ANSYS software to analyze the critical speed. Compared with dry condition,the critical speed of wet condition increased. The first order “wet” critical speed is 4 738 r/min,which is much larger than the actual speed 2 980 r/min. Meanwhile,APDL program is used to reduce the 3D centrifugal modal under wet condition due to many degrees of freedom,stress stiffening and coriolis effect are considered. 68% degrees of freedom of pump rotor model are reduced. The maximum critical speed error is 0.17%. Unbalance response calculated by the reduced modal is just the same as the non-reduced modal.