基于补偿切割法的离心泵轴向力控制试验

为解决切割叶轮后盖板平衡轴向力的方法会导致泵扬程和效率降低这一关键问题,提出了一种补偿叶轮后盖板切割量平衡轴向力的方法。采用在同一个叶轮上切割叶轮后盖板和补偿叶轮后盖板切割量的研究方案,开展了泵性能、叶顶间隙压力、前后泵腔及平衡腔液体压力的系统测量。试验研究表明：以原型叶轮在设计流量下的扬程、效率和轴向力为基准,相对切割率为3.81%、7.62%、11.43%时,泵的扬程分别下降了3.52%、6.41%、9.93%,效率分别下降了2.97%、4.59%、6.18%,轴向力分别降低了8.02%、20.57%、22.3%;而补偿叶轮后盖板切割量后,泵的扬程最大降幅仅为4.18%,效率最大降幅仅为2.7%,轴向力最大降幅达到了83.1%;相对于切割叶轮后盖板而言,补偿叶轮后盖板切割量可以使前泵腔压力升高而后泵腔压力降低。

Experiment of axial force control for centrifugal pump based on compensation trimming method

To solve the key problem that trimming rear shroud of impeller balanced axial force could reduce the pump head and efficiency, a method to balance axial force by compensating rear shroud of impeller cut was proposed. On the same impeller, systematic measurements of the pump performance, tip clearance pressure, liquid pressure distribution in front and rear pump cavity and liquid pressure in balanced cavity were carried out with the research scheme of trimming rear shroud of impeller and compensating rear shroud of impeller. The experiment results showed that at the designed speed and flow rate, the relative trimming rates of rear shroud of impeller were 3.81%, 7.62% and 11.43%, respectively, the pump head was 3.52%, 6.41%, 9.93% lower than that of the prototype impeller, the efficiency was 2.97%, 4.59% and 6.18% lower than that of the prototype impeller, and the axial force was 8.02%, 20.57% and 22.3% lower than that of the prototype impeller. After compensating rear shroud of impeller trimming, the maximum drop of pump head was 4.18%, the maximum drop of efficiency was 2.7%, and the maximum drop of axial force was 83.1%. Compared with cutting rear shroud of impeller, compensating rear shroud of impeller trimming can increase the pressure of the front pump cavity and reduce the pressure of the rear pump cavity.