Experiment of axial force control for centrifugal pump based on compensation trimming method
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摘要:
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。
Abstract: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.
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Key words:
- centrifugal pump /
- axial force /
- impeller shroud /
- trimming /
- compensation
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表 1 IS80-50-315型离心泵性能参数和主要几何参数
Table 1. Performance parameters and main geometric parameters of IS80-50-315 centrifugal pump
设计参数 数值 额定流量Qsp/(m3/h) 25 额定扬程H/m 32 额定转速n/(r/min) 1450 额定效率η/% 52 比转速ns 34 叶轮外径D/mm 315 叶片数Z 5 叶片包角$ \varphi $/(°) 170 前后密封环直径Dm/mm 90 前后密封环间隙b/mm 0.25 前后密封环长度L/mm 15 后泵腔轴向宽度b1/mm 4 平衡孔直径d/mm 6 平衡孔数z 5 表 2 后密封环间隙进口压力和平衡腔压力的减小值
Table 2. Reduction value of rear seal ring clearance inlet pressure and balance cavity pressure
切割方案 压力减小值/kPa ${{ - } }\Delta {p_1}$ ${{ - } }\Delta {p_2}$ 方案一 7 1 方案二 14 3 方案三 22 4 方案一补偿 11 3 方案二补偿 17 4 方案三补偿 27 6 -
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