施卫东, 程成, 张德胜, 邢津, 陈刻强. 后掠式双叶片污水泵优化设计与试验[J]. 农业工程学报, 2014, 30(18): 85-92. DOI: doi:10.3969/j.issn.1002-6819.2014.18.011
    引用本文: 施卫东, 程成, 张德胜, 邢津, 陈刻强. 后掠式双叶片污水泵优化设计与试验[J]. 农业工程学报, 2014, 30(18): 85-92. DOI: doi:10.3969/j.issn.1002-6819.2014.18.011
    Shi Weidong, Cheng Cheng, Zhang Desheng, Xing Jin, Chen Keqiang. Optimal design and experiment of back swept double blades sewage pump[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2014, 30(18): 85-92. DOI: doi:10.3969/j.issn.1002-6819.2014.18.011
    Citation: Shi Weidong, Cheng Cheng, Zhang Desheng, Xing Jin, Chen Keqiang. Optimal design and experiment of back swept double blades sewage pump[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2014, 30(18): 85-92. DOI: doi:10.3969/j.issn.1002-6819.2014.18.011

    后掠式双叶片污水泵优化设计与试验

    Optimal design and experiment of back swept double blades sewage pump

    • 摘要: 为了解决污水处理用排污泵叶轮易堵塞和磨损问题,该文设计了一种新型后掠式双叶片污水泵叶轮结构。采用正交试验的方法,按照L9(34)正交表,选取了叶片出口安放角β2、叶轮进口直径Dj、叶片出口宽度b2以及叶轮出口直径D2等因素,设计出了9组方案,通过正交试验分析了4个几何参数对泵性能的影响,得出叶轮出口直径D2是影响效率和扬程的最主要因素,并提出了优化设计方案。基于k-ε湍流模型及离散相零方程模型,对污水泵进行了固液两相流数值模拟,并将数值模拟结果与样机试验结果进行了分析对比。结果表明,双叶片、大包角、叶片前缘后掠的设计方法,可使颗粒杂质向外输送至叶片外周边,保证了固体颗粒或纤维的顺利通过,大幅降低了叶片的磨损,从而提高了泵的使用寿命,同时还具有较高的效率。通过样机试验得到优化设计方案在额定流量点的效率为80%,扬程为11 m,效率高于国家标准2.5%,该水力设计方法对污水泵水力设计具有一定的参考价值。

       

      Abstract: Abstract: This article proposed a typical impeller structure of new type of sewage pump to solve the blocking and wear problem in sewage pumps. Using an orthogonal experiment of L9(34), which contains factors of outlet blade angleβ2, impeller inlet diameter Dj, impeller outlet width b2, and impeller outlet diameter D2, nine groups of schemes were designed. Four geometric parameters were researched to analyze the influence on sewage pump performance by orthogonal experiments. Optimized design schemes were achieved, and we conclude that impeller outlet diameter D2 is the main factor that affects the efficiency and pump head. Second, the solid-liquid two-phase flow was studied on the basis of a turbulence model and a model of the discrete-zero equation. On the basis of the orthogonal optimization model, the back-swept angle was changed to study the different particle distributions associated with the back-swept angle and non-back-swept angle. We further explored the effect of the back-swept angle on sewage pump performance. The angles were 60 degrees, 80 degrees, 100 degrees, and 120 degrees, respectively. The research shows that the degree of swept-back angle has little influence on sewage pump head. Nevertheless, it has significant influence on pump efficiency when the solid particle diameter is 0.4 mm and the solid volume fraction is 5 percent. The optimization model was made into a prototype with the swept angle of 80 degrees in the plant of Nanjing LanShen Pump Co., LTD, to perform the experiment. The test system consisted of an electric pump, a torque sensor, and a pressure sensor. By comparing numerical results with experimental results, the result indicates that the double bladed, large wrap angle, and leading edge sweep design make the particles move around the outer perimeter of the blades to ensure the passage capacity and operational efficiency of sewage pumps and greatly reduce the wear of blade. Consequently, the service life of the sewage pump can be improved. The rotation of the impeller caused the velocity variation in the back-swept sewage pump and velocity circulation amount distributes around the flow field. The inlet velocity rotated with the impeller high-speed revolution, and the outlet velocity changed radically. The figure illustrates that the solid volume fraction in the pressure side is greater than that in the suction side. That is, particles move towards the pressure side of blade. Therefore, wear and tear on the pressure side is more serious than the suction side. The distribution of total pressure and solid volume fraction are different from the pressure to the suction side. When the back-swept angles are 60 degrees and 80 degrees on the suction side, the total pressure follows a declining trend from the suction side to the pressure side. It means that the field near the imports falls sharply, and then falls gently. However, the total pressure decreases initially and then begins to increase with the increase of the back-swept angle, when the angles are 100 degrees and 120 degrees. At the same time, the solid volume fraction exhibits a downward trend. According to the test results, the efficiency of the model pump can reach 80% with a pump head of 11 m at rated conditions. The test result is 2.5% higher than the National Standard.

       

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