Abstract

To improve the calculation accuracy for the mechanics mode of a double-support four-stage centrifugal pump rotor system (FCPRS), a simplified mathematical model derived from “four segments-four concentrations” and an ANSYS model were used to solve the model of a D-type FCPRS with balanced mass. Based on ourresults, we present an improved mathematical model combining "five segments-four concentrations" and the modal resistance-bending stiffness (RBS) correction coefficient. Moreover, the calculation results of the impeller mass eccentricity from the optimized model were compared with those from ANSYS simulations. The natural frequencies (NF) from the concentrated mass method (CMM) are slightly lower than those obtained from ANSYS. After optimization, the errors of the first four orders of NFs decreased from 1.13%, 1.24%, 7.62%, and 7.96% to 0.79%, 0.90%, 4.17%, and 4.51%, respectively. The NFs of each order increase slightly in the case of impeller mass eccentricity. The low-order NF increases slightly and the high-order NF decreases when the impeller in the middle is eccentric. The NF error obtained via the optimized CMM for the impeller with eccentric mass is slightly larger than that for the impeller without eccentricity.

摘要

为提高双支撑四级离心泵转子系统（FCPRS）力学模态计算精度，采用“四段四集中”简化数学模型和ANSYS模型求解质量平衡的 D 型 FCPRS。基于我们的研究结果，我们提出了一种结合“五段四浓度”和模态抗弯刚度（RBS）修正系数的改进数学模型。此外，将优化模型的叶轮质量偏心计算结果与ANSYS仿真的结果进行了比较。集中质量法 (CMM) 的固有频率 (NF) 略低于 ANSYS 的固有频率。优化后，NFs前四阶的误差分别从1.13%、1.24%、7.62%、7下降。分别为 96% 至 0.79%、0.90%、4.17% 和 4.51%。在叶轮质量偏心的情况下，每个阶的 NF 略有增加。当中间叶轮偏心时，低阶NF略有增加，高阶NF减小。通过优化三坐标测量机获得的偏心质量叶轮的 NF 误差略大于无偏心叶轮的 NF 误差。