轴流泵转子系统水中模态分析

Modal analysis of axial-flow pump rotor system in water

为了研究轴流泵转子系统在水中的模态以及水介质对于模态的影响,保障轴流泵机组高效稳定运行,避免发生共振,采用基于流固耦合的理论对ANSYS Workbench平台进行二次开发,通过编写APDL语言实现流体与固体计算方程的耦合,计算轴流泵转子系统在空气中以及水中的模态.结果表明:与流场计算不同,模态分析过程中对结构域进行三维建模时,不能将结构中的空心部分简化为实体;水介质的存在使得转子系统各阶固有频率均有下降,频率降低系数的幅度为7.95%~13.29%,各阶频率的下降系数未呈现出显著的规律性;轴流泵的叶片通过频率为15 Hz,导叶通过频率为25 Hz,这2个机组特征频率的值远小于转子系统在水中的各阶固有频率,可以认为轴流泵在工作过程中发生共振的可能性比较小.

Studying the modal of axial-flow pump rotor system in water and the impact of water on mo- dal is important to ensure the efficiency, stable running of the pump and to avoid resonance. By se- condly developing the ANSYS Workbench based on fluid - solid coupling theory, we compiled APDL language to couple the fluid and solid calculation equation so as to calculate the modal of axial-flow pump rotor system in air and water. The results show that when the three-dimensional modeling of structure domain was carried out before modal analysis, the hollow portion of structure cannot be sim- plified to solid area, which is different from flow field analysis. The existence of water makes each or- der natural freouencv of rotor svstem declines. The denreciation coefficient ranges from 7.95% to13.29% and each order depreciation coefficient does not show an obvious rule. The blade passing fre- quency of axial-flow pump is 15 Hz and the guide passing frequency of axial-flow pump is 25 Hz, which are much less than each order natural frequency of axial-flow pump rotor system in water, so it is less likely to generate resonance during running time.