双吸离心泵压力脉动是影响水泵机组运行稳定性的关键因素之一。采用试验的方法,分别在吸水室和压水室的壁面布置压力脉动传感器,采集各个测试流量下的压力脉动信号,进行混频幅值和频谱分析。结果表明,低于轴频的低频脉动和轴频脉动在吸水室区域占主导地位。在额定流量和大流量工况下,低频脉动频率主要为1/3倍的轴频。在小流量工况下,该低频脉动影响范围显著扩大,幅值明显增大。叶频脉动在隔舌区域非常强烈,是压水室区域的主导脉动成分,沿压水室圆周方向传播并耗散脉动能量。当偏离额定工况时,压水室压力脉动峰峰值显著增加,尤其是在小流量工况,该幅值达到额定工况下相应值的5~6倍。%Pressure fluctuations in double-suction centrifugal pumps caused by internal flow are the primary sources of operation instability. By means of pressure transducers installed in suction chamber and volute wall, fluctuating pressure signals were obtained and recorded at various operation conditions. The signals in time and frequency domains of the signals were analyzed by using the fast Fourier Transform Method. The results show that rotating frequency and some lower frequencies are dominative in suction chamber. The lat- ter is adjacent to the 1/3 rotating frequency at the design and higher flow rates. While at partial flow rates, the magnitudes as well as the range of the lower frequencies become notably larger. Blade passage frequency dominates the pressure fluctuations in volute, of which the magnitude becomes relatively smaller when the position is far away from the volute tongue in peripheral direction. The peak-peak value of pressure fluctuation increases remarkedly as the flow rates deviate from the designed one and reaches 4-5 times higher at the partial flow rates.
展开▼
