自吸泵数值模拟及结构优化

发布时间：2019-01-08 13:46

【摘要】：自吸泵作为一种特殊的离心泵,主要应用于工业特殊领域。自吸泵在首次启动之前需要向泵内灌液,以后再次启动时无需灌泵。本文在总结国内外学者对于自吸泵研究的基础上,进一步对自吸泵的自吸过程做了研究探讨。首先,对立式导叶自吸泵结构、原理做了介绍,并对关键过流部件叶轮、导叶进行了设计;然后利用CFX软件对自吸泵进行了定常液相模拟,分析揭示了叶轮流道内绝对速度、相对速度、压力分布情况,然后对预测获得的泵模拟性能曲线与试验曲线进行对比,发现二者吻合度较好,从而证明了所用模型较好。然后,利用非稳态数值模拟方法模拟自吸泵自吸过程,初始条件为进水管及出水管含有部分空气,分析了泵在自吸过程中泵内气液两相分布情况、叶轮与导叶中流动演变情况;通过CFX提供的函数获得叶轮进口、泵出口气相流量随时间变化规律,并由泵出口气相流量估算出泵的自吸时间;由于气液分离室是气液混合与分离的主要场所;因此,分析了分离室内有挡板对泵自吸过程影响,并将其与无挡板时自吸情况进行对比。最后,对自吸泵进行了正交模拟设计。根据分析选取四个对自吸性能有影响的因素进行模拟设计,通过对数据处理和分析,得出各因素对试验指标影响的主次顺序,并获得最佳方案。通过指标因素图发现叶轮与导叶间隙是自吸时间和自吸高度的主要影响因素;因此进一步探讨叶轮与导叶间隙对自吸时间影响,分析发现,间隙存在一个最佳值。
[Abstract]:As a special centrifugal pump, self-priming pump is mainly used in industrial special field. The self-priming pump needs to be pumped before the first start, and not to be pumped when it starts again. On the basis of summarizing the research of self-priming pump at home and abroad, the self-priming process of self-priming pump is further discussed in this paper. Firstly, the structure and principle of self-priming pump with opposite guide vane are introduced, and the impeller and guide vane are designed. Then, the steady liquid phase simulation of the self-priming pump is carried out by using CFX software, and the absolute velocity, relative velocity and pressure distribution in the impeller passage are analyzed and revealed. Then the predicted simulation performance curve is compared with the experimental curve. It is found that the two models are in good agreement with each other, which proves that the model used is better. Then, the self-priming process of self-priming pump is simulated by unsteady state numerical simulation method. The initial condition is that the inlet pipe and outlet pipe contain part of air. The gas-liquid two-phase distribution in the pump and the flow evolution in impeller and guide vane are analyzed in the process of self-priming. According to the function provided by CFX, the variation law of gas phase flow at the pump outlet with time is obtained, and the self-priming time is estimated from the pump exit gas phase flow, because the gas-liquid separation chamber is the main place for gas-liquid mixing and separation. Therefore, the influence of the baffle on the self-priming process of the pump is analyzed and compared with the self-priming process without the baffle. Finally, the orthogonal simulation design of the self-priming pump is carried out. According to the analysis, four factors which have influence on the self-priming performance are selected to simulate the design. Through the data processing and analysis, the primary and secondary order of the influence of each factor on the test index is obtained, and the best scheme is obtained. It is found that the clearance between impeller and guide vane is the main influencing factor of self-priming time and height, so the influence of impeller and guide vane clearance on self-priming time is further discussed, and it is found that there is an optimum value of clearance.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH317

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