转轴动力学特性对离心泵压力脉动的影响分析

Influence of Shaft Dynamic Characteristics on Pressure Pulsation of Centrifugal Pump

对于电动泵的研究而言,离心泵、转轴和电机应视为一个完整的系统来分析。若忽略了设备间的相互影响,单独对系统中的某一设备进行分析计算将可能无法通过仿真模型计算得到实验过程中出现的所有频率成分。本文建立了包括电机、转轴和泵在内的多场耦合仿真模型,用于分析轴在扭转方向的动力学特性对泵运行状态的影响。首先,建立了电机与水泵的仿真模型,并用转轴将其联系起来,实现系统的耦合仿真模拟;然后,计算了电机、转轴和水泵在相互作用影响下的转速波动情况和泵出口的压力脉动情况。结果表明,系统中不同设备间的转矩和转速是相互联系的;转轴同时连接着电机与水泵,其扭振特性也会在水泵瞬时转速的频率成分中体现;水泵运行转速的波动会进一步影响其壁面压力脉动的特性,最终可能导致在泵壳的振动信号中出现与水泵自身无关的频率成分。

For the research of electric pumps,the centrifugal pump,shaft and motor should be analyzed as a complete system.When ana-lyzing a certain device in the system alone,since the mutual influence between the devices is ignored,the simulation model may not be able to calculate all the frequency components that appear in the experiment.In this paper,a multi-field coupled simulation model including motor,shaft and pump is established to analyze the influence of shaft torsional vibration mechanical characteristics on the pump.Firstly,the simulation model of the motor and the water pump is established,combining the shaft to realize the system coupled simulation;then,the rotational speed fluctuation of the motor,shaft,and water pump under the mutual influence and the pressure pulsation at the pump outlet are calculated.The results show that the torque and rotational speed of different devices in the system are related to each other.The shaft is connected to the motor and the water pump at the same time,and its torsional vibration characteristics are also reflected in the frequency component of the instantaneous speed of the water pump.The fluctuation of the running speed of the pump will further affect the characteristics of its wall surface pressure pulsation,which may eventually leads to the appearance of frequency components which unrelated to the pump itself in the vibration signal of the pump casing.