不同空化条件下凝水泵内压力脉动特征

Characteristics of Pressure Fluctuations in a Condensate Pump Under Different Cavitation Conditions

对一台凝水泵进行压力脉动实验研究。该凝水泵的叶轮由5长5短叶片组成,叶轮上下游分别设置导流栅和径向导叶。结果表明,该泵的临界汽蚀余量小于1m。低转速条件下,泵的总体压力脉动较高转速条件下低,但同流量下,泵的空化性能较高转速时差。随着泵进口压力的降低,叶频和1/2叶频对应的压力脉动幅值呈现下降趋势,并于空化临界点附近剧增。而小流量工况下,随着空化的发展,叶频被抑制,同时1/2叶频对应的压力脉动幅值呈现不规则变化。

An experimental study on pressure fluctuations in a condensate pump was carried out.The pump is featured by an impeller with five long and five short blades,which is matched with an upstream guide vane and a downstream diffuser.The results show that the critical NPSH of the pump considered is less than 1 m.With the decrease in the rotational speed,the overall pressure fluctuation magnitude declines;while at the same flow rate,the cavitation performance is worse than that associated with high rotational speed.As the inlet pressure of the pump decreases,the pressure fluctuation amplitudes corresponding to the blade passing frequency and half the blade passing frequency drop,but rise drastically near the critical cavitation point.For low flow rates,the blade passing frequency is suppressed with the development of cavitation,and the pressure fluctuation amplitude corresponding to half the blade passing frequency exhibits an irregular variation pattern.