离心泵隔舌区压力脉动测量与分析

离心泵内部的压力脉动是引起机组振动及噪声的主要原因,这一现象在隔舌区尤为严重。对某单吸离心泵在变转速和变流量工况下的性能及隔舌区的压力脉动进行了定量试验研究。试验结果表明:离心泵运行在小流量工况时,其性能随转速工况的变化基本符合离心泵一维设计理论。隔舌区压力脉动测量结果表明:压力脉动以离散分量为主,其整体强度占参考动压的1%左右,且随转速近似以二次函数形式变化。定转速时,随着流量的减小隔舌外侧压力脉动强度变化不明显,但舌尖及内侧压力脉动强度有明显提高,这归因于低频压力脉动的增大。研究结果对泵类系统的减振降噪和安全性改善具有指导意义。

Pressure Fluctuations around Volute Tongue of Centrifugal Pump

Pressure fluctuations inside centrifugal pump, especially those near the volute tongue, are the primary excitations to pump vibration and noise. The performance and pressure fluctuations of a centrifugal pump running at different flow rates and variable speeds were experimentally studied. The pump performance measurement showed that the pump worked at low flow rate condition, and the pump hydraulic performance varied with the rotational speed according to one-dimensional design theory. The pressure fluctuation measurement showed that discrete components were the main contributions in the pressure fluctuation spectra, especially the blade passing frequency (BPF) and its second harmonic. The overall strength of pressure fluctuation was approximately 1% of the reference dynamic pressure, and it varied in a quadratic function form with rotary speed. At a constant rotation speed, the pressure fluctuation magnitude at the outlet side of volute tongue had no obvious change with the decrease of flow rate, but places at the inner side and tongue tip experienced noticeable increase at sufficiently low flow rates owing to the pressure fluctuations below BPF. The study provided a basis for future study of flow-induced pump vibration and noise.