全贯流泵回流间隙对泵水力性能的影响

Influence of Backflow Gap Size on Hydraulic Performance of Full-flow Pump

为了研究全贯流泵回流间隙对泵水力性能的影响,利用CFD软件对全贯流泵装置进行了数值模拟计算,分析了全贯流泵装置的流动特性和水力性能,并通过模型试验验证了计算数据的可靠性。研究结果显示:回流间隙对全贯流泵的水力性能有较大的影响,且随着电机转子间隙的增大,泵装置在设计工况下的效率和扬程均逐渐降低。当回流间隙为0.65 mm时,全贯流泵在设计工况下的扬程为3.05 m,效率为82.46%,最高效率为82.66%。当回流间隙为2 mm时,全贯流泵在设计工况下的扬程为2.92 m,效率为80.85%,最高效率为81.27%,两种回流间隙的泵装置在设计工况下的扬程差值为0.13 m,效率差值为1.61个百分点。随着流量的增大,全贯流泵叶轮进出口的压差逐渐减小,间隙回流流量也逐渐减小,间隙回流对叶轮进出口的流态影响也减小。距离轮缘越近,回流对流态的影响越大。随着回流间隙的增大,全贯流泵的间隙流量变大,间隙回流对叶轮进出口的流态影响增大,叶轮的做功能力逐渐变差,全贯流泵的扬程和效率均逐渐下降。

In order to study the influence of gap backflow of full-flow pump impeller on hydraulic performance,the CFD software was used to carry out numerical simulation calculation of the full-flow pump. Then the flow characteristics and hydraulic performance of the full-flow pump were analyzed.Finally,the reliability of numerical calculation data was verified through model tests. There were two research directions: the first one was to study performance difference of the full-flow pump under different flow conditions when the gap was constant. The second one was to study the performance difference of the full-flow pump with different gaps under the design condition. The results showed that the gap size had an obvious impact on the hydraulic performance of full-flow pump. With the increase of gap size,the efficiency and head of the pump devices were reduced under the design condition. When the minimum gap size was 0. 65 mm,the head of the full-flow pump was 3. 05 m under the design condition,and the efficiency was 82. 46%. The highest efficiency was 82. 66%. When the maximum gap size was 2 mm,the head of the full-flow pump was 2. 92 m under the design condition,and the efficiency was 80. 85%.The highest efficiency was 81. 27%. The difference of the head between two pump devices was 0. 13 m under the design condition,and the difference of the efficiency was 1. 61 percentage points. With the increase of the flow rate,the difference of the pressure between inlet and outlet was gradually decreased.The backflow rate was also gradually decreased. The influence of backflow on the impeller was small.And close to the rim,the effect of backflow on the flow regime was great. With the increase of the gap size,the backflow of the full-flow pump was increased. The influence of full-flow pump on flow state was heavy. The working ability of the impeller was worse. The head and efficiency of the full-flow pump were gradually decreased. The research can provide a basis for the design and development of the full-flow pump.