双向轴伸泵装置反向运行流动及振动特性研究

Flow and Vibration Characteristics of the Bidirectional Shaft Extension Pump in Reverse Operation

为分析双向轴伸泵装置反向运行时的流动特性,对泵装置进行数值模拟计算,结果表明:泵装置反向运行时,前置导叶引起的正向预旋使叶轮进口处的轴向流速分布均匀性降低,当流量小于0.8Q0时,轴向流速分布均匀性呈现出近乎指数的下降趋势;叶轮出口环量越大,出水流道性能的提高越明显,但是当流量大于1.1Q0时,环量对流道性能的影响消失。通过模型试验验证外特性,然后对试验装置不同叶片安放角、不同工况下的振动结果进行分析,得到其振动特性,结果表明:泵装置反向运行时,振动加速度峰峰值随着流量的减小先减小后增大,在小流量工况0.8Q0时最大;振动主频集中在1倍、3倍、4倍和14倍转频的位置,且主频位置随工况的改变而改变.研究结果为泵站工程的安全稳定运行提供参考。

In order to analyze the flow characteristics of the bidirectional shaft extension pump in reverse operation,the numerical simulation of the pumping system was carried out,and the results showed that:in the reverse operation of the pumping system,the forward pre-rotation caused by the inlet guide vane reduces the uniformity of axial velocity distribution of the impeller inlet.Especially when the flow rate was less than 0.8 times design flow,the uniformity of axial velocity distribution decreased exponentially.The larger circulation of the impeller outlet was,the more efficient the outlet passage would be,but when the flow rate was more than 1.1 times design flow,circulation’s influence on the performance of the outlet passage would disappear.The external characteristics were verified by the model test,and the vibration results of the test device under different blade angles and different operating conditions were analyzed for vibration characteristics.The results showed that:when the pumping system operated reversely,the peak to peak values of vibration acceleration decreases first and then increases with the decrease of flow rate,which are the largest under 0.8 times design flow condition.The dominant frequency of vibration was 1,3,4 and 14 times of rotating frequency and the position of the dominant frequency changed with the changes of working condition.The research results provide a reference for the safe and stable operation of the pump stations.