不同流量工况灯泡贯流泵压力脉动混沌特性

Chaotic analysis of pressure fluctuation in bulb tubular pump under different flow conditions

灯泡贯流泵机组振动来源十分复杂,为了分析机组振动规律,从流场压力脉动出发,分析其混沌特性,从而指出贯流泵站机组振动特征源自流场压力脉动特性的影响.为了研究不同工况下灯泡贯流泵压力脉动混沌特性,在贯流泵机组叶轮导叶、灯泡体壁面和流道内部设置压力脉动监测点,通过相空间重构、最大Lyapunov指数、相轨迹图、分形标度、关联维数分析各工况下各个监测点压力脉动信号混沌特性.结果表明:泵机组内部特定位置压力脉动信号最大Lyapunov指数大于0,信号具有混沌特性;3种流量工况下,叶轮进口处监测点压力脉动信号关联维数为2.00~2.50,叶轮出口处为1.80~2.00,导叶出口处为1.20~1.50,流道内普遍大于2.00,不同流量下关联维数亦有差异,可以通过关联维数判断泵机组是否有偏工况运行以及是否存在异常水力脉动的情况,研究结论可为泵站防治异常水力振动提供参考.

The vibration source of bulb tubular pump unit is very complex.In order to analyze the vibration law of the unit,the chaotic characteristics of flow field pressure fluctuation were analyzed,and it was pointed out that the vibration characteristics of tubular pump unit originated from the influence of flow field pressure fluctuation.In order to study the chaotic characteristics of pressure fluctuation in the bulb tubular pump under different working conditions,setting up pressure fluctuation monitoring points in impeller,guide vane,bulb wall and flow channel,the chaotic characteristics of pressure fluctuation signals at each monitoring point were analyzed by phase space reconstruction,maximum Lyapunov exponent,phase trajectory,fractal scale and correlation dimension.The results show that the maximum Lyapunov exponent of the pressure fluctuation signal at a specific position in the pump unit is larger than 0,and the signal has chaotic characteristics.Under the three flow conditions,the correlation dimension of the pressure fluctuation signal at the monitoring point at the impeller inlet is between 2.00-2.50,the impeller outlet is between 1.80-2.00,the guide vane outlet is between 1.20-1.50,and the flow channel is general above 2.00.The correlation dimension of different flows conditions is also diffe-rent,the correlation dimension could be used to judge whether the pumps have off design working condition and abnormal hydraulic fluctuation.The conclusions can provide a reference for the prevention and control of abnormal hydraulic vibration of pumping stations.