立式自吸离心泵动密封影响因素研究

Research on Influencing Factors of Dynamic Seal of Vertical Self-priming Centrifugal Pump

为了研究自吸泵副叶轮几何参数及平衡孔位置对副叶轮密封能力的影响,根据实际工程应用选取副叶轮不同结构叶片形式、叶片个数以及排气孔大小3个因素,每个因素选取3个水平变量,按L(3~3)正交试验方案,设计了9组自吸泵副叶轮密封结构方案。通过CFD数值计算方法对自吸泵的全流场进行三维数值分析,采用RNG κ-ε湍流模型和多重参考系的雷诺时均N-S方程,获得影响副叶轮密封能力的3个因素的最优匹配关系,并结合试验结果进行分析。结果表明:在满足自吸泵动力密封的情况下,副叶轮叶片结构形式对自吸泵密封能力影响较大,其次是副叶轮叶片个数及排气孔大小。同时发现,在副叶轮密封腔上开设排气孔可以明显缩短自吸泵的自吸时间。通过正交试验方案对比,自吸泵副叶轮动力密封设计时采用径向型直叶片结构形式、选取合适的叶片数并配合密封腔排气孔,可以使动力密封结构具有良好的密封能力并有效提高自吸泵的性能。

The purpose of this paper is to study the influence of the geometric parameters of the auxiliary impeller of the self-priming pump and the position of the balance hole on the sealing ability of the auxiliary impeller.According to the actual engineering application, three factors which are different structure blades of the auxiliary impeller, the number of blades and the size of the exhaust holes were selected, and three horizontal variables for each factor were selected.According to the L(3~3) orthogonal test scheme, 9 sets of auxiliary impeller sealing structure scheme of self-priming pumps are designed.The three-dimensional numerical analysis of the full flow field of the self-priming pump is carried out through the CFD numerical calculation method.The RNG κ-ε turbulence model and the Reynolds time-averaged N-S equations of multiple reference systems are used to obtain the optimal matching relationship of the three factors affecting the sealing ability of the auxiliary impeller, and then analyze the test results.The results show that when the power seal of the self-priming pump is satisfied, the structure of the auxiliary impeller blades has a greater impact on the sealing ability of the self-priming pump, followed by the number of auxiliary impeller blades and the size of the exhaust holes.At the same time, it was found that opening a vent hole in the sealing cavity of the auxiliary impeller can significantly shorten the self-priming time of the self-priming pump.Through the comparison of orthogonal test schemes, the design of the power seal of the auxiliary impeller of the self-priming pump adopts the backward curved blade structure and the appropriate number of blades and matches the size of the exhaust hole of the seal cavity, which can make the dynamic seal structure have good sealing ability and effectively improve self-priming pump performance.