基于CFD的带分流叶片离心泵内部流场及性能研究

发布时间：2018-10-20 20:09

【摘要】：离心泵是一种广泛应用于国民经济各个领域的通用水力机械,按照传统方法设计的离心泵都有效率低、易过载、扬程曲线出现驼峰、小流量工况下不稳定以及运行时容易产生振动和噪声等问题,添加分流叶片设计法是目前解决上述问题,改善离心泵性能最有效的方法之一。针对已往研究的带分流叶片离心泵结构较为单一,本文首先对一种已往研究较少的长中短叶片离心泵进行研究,然后设计出一种结构新型的双分流叶片离心泵,并进行研究,以期为带分流叶片离心泵的结构设计提供新的思路和方法,最后利用非定常数值计算的方法探索分流叶片对泵体诱导振动和噪声的影响。主要工作和结论有： (1)以IS50-32-125型离心泵作为模型泵,建立了计算模型和确定了数值计算方法,探讨了湍流模型、网格尺寸和收敛精度对计算结果的影响,并通过离心泵外特性试验,验证了本文所采用的计算模型和计算方法的准确性。 (2)在模型泵的基础上设计出长中短叶片离心泵,并采用正交数值模拟研究的方法对长中短叶片离心泵叶轮的主要几何结构参数,如中分流叶片进口直径、短分流叶片进口直径、中短分流叶片周向偏置度等3个因素进行研究,获得了各几何结构参数与离心泵性能之间的关系,同时得到了各几何结构参数对离心泵性能影响的主次顺序。设计出的最佳长中短叶片离心泵扬程在全流量工况范围内比模型泵提高了16.59%～47.15%,整机效率在大流量区域比模型泵提高了0.78%～12.67%。 (3)在模型泵的基础上设计出双分流叶片离心泵,并通过数值模拟的方法探讨了双分流叶片离心泵叶轮主要几何结构参数,如双分流叶片进口直径、双分流叶片周向偏置度及叶片数对离心泵内部流场及整机性能的影响,得出了各几何结构参数的最优设计取值。设计出的最佳双分流叶片离心泵,扬程在全流量工况范围内比模型泵增加了15.02%～36.63%,效率在大流量区域比模型泵提高了1.92%～12.44%,而且扬程曲线更加平坦,效率曲线向大流量方向偏移,高效区也变宽了。 (4)采用滑移网格技术对4种不同叶轮类型的离心泵在小流量工况、最佳工况和大流量工况下进行非定常数值计算,由此获得了4种离心泵在一个周期内不同时刻的压力分布情况,同时在蜗壳流道内设置了6个监测点,监测各处压力随叶轮旋转的变化曲线,最终结果表明：采用长中短叶片布置或添加双分流叶片可使离心泵流道内的压力波动大幅减小,有效地改善了离心泵的诱导振动和噪声情况。
[Abstract]:Centrifugal pump is a kind of universal hydraulic machinery widely used in various fields of national economy. The centrifugal pump designed according to the traditional method is of low efficiency, easy to overload, and the head curve appears hump. Under the condition of small flow rate instability and vibration and noise are easy to be produced during operation. Adding shunt vane design method is one of the most effective methods to solve these problems and improve the performance of centrifugal pump. In view of the single structure of previously studied centrifugal pump with split vane, this paper first studies a kind of centrifugal pump with long, medium and short vane, which has been studied less, then designs a new type of centrifugal pump with double shunt vane, and carries on the research. In order to provide a new idea and method for the structural design of centrifugal pump with split blade, the unsteady numerical calculation method is used to explore the influence of shunt blade on the induced vibration and noise of pump body. The main work and conclusions are as follows: (1) taking IS50-32-125 centrifugal pump as model pump, the calculation model and numerical calculation method are established, and the effects of turbulence model, mesh size and convergence accuracy on the calculation results are discussed. The accuracy of the calculation model and calculation method used in this paper is verified by testing the external characteristics of the centrifugal pump. (2) the long, medium and short vane centrifugal pump is designed on the basis of the model pump, and the centrifugal pump with long, medium and short vane is designed on the basis of the model pump. The main geometric parameters of centrifugal pump impeller with long, medium and short blades, such as inlet diameter, inlet diameter and circumferential bias, are studied by orthogonal numerical simulation. The relationship between the geometric structure parameters and the performance of the centrifugal pump is obtained, and the primary and secondary order of the influence of the geometric structure parameters on the performance of the centrifugal pump is obtained. The designed head of the best centrifugal pump with long, medium and short vane is 16.599.59% higher than that of the model pump in the range of full flow. The efficiency of the whole machine is 0.78% higher than that of the model pump in the large flow area. (3) the model pump is designed on the basis of the model pump. Double shunt vane centrifugal pump, The influence of the main geometry parameters of the centrifugal pump impeller, such as the inlet diameter of the double shunt blade, the circumferential bias degree of the double shunt blade and the number of blades, on the internal flow field and the performance of the whole centrifugal pump is discussed by numerical simulation. The optimum design value of each geometric structure parameter is obtained. The optimum centrifugal pump with double shunt vane is designed. The lift is increased by 15.02% and 36.63% compared with the model pump in the range of full flow condition. The efficiency is 1.92% higher than that of the model pump in the large flow area, and the lift curve is more flat. The efficiency curve is shifted to the direction of large flow rate, and the high efficiency zone is widened. (4) the unsteady numerical calculation of four different impeller types of centrifugal pumps under small flow, optimum and large flow conditions is carried out by using slippage grid technique. The pressure distribution of the four centrifugal pumps at different times in one cycle is obtained. At the same time, six monitoring points are set up in the volute runner to monitor the curves of pressure variation with the impeller rotation. The final results show that the pressure fluctuation in the centrifugal pump channel can be greatly reduced by using long, medium and short blades or by adding double shunt blades, and the induced vibration and noise of centrifugal pump can be effectively improved.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311

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