【作者】 熊茂涛；

【导师】 陈次昌； 杨昌明；

【作者基本信息】 西华大学 ， 动力机械及工程， 2006， 硕士

【摘要】 离心式水泵是一种通用水力机械,主要用于管道水力输送。在含沙水流中其主要失效形式是叶轮的磨损。其内部的固液两相流情况一直是水泵设计人员十分关注的问题,因为泵内流动的优劣直接影响水泵的性能。离心泵的内部流动是很复杂的湍流流动,同时由于受旋转、叶片表面曲率和泥沙颗粒的影响,还拌有脱流、回流等流动现象,是流体工程中较难的试验研究和数值计算问题之一。 本课题从计算流体动力学出发,分析对比了湍流的几种计算理论和方法,在对含沙水流中离心式水泵过流表面磨损机理理解的基础上,以YLB50-20水泵叶轮为例,根据κ-ε理论,选用Mixture模型,利用ProE软件建立了水泵内部过流通道的几何模型,采用GAMBIT软件贴体坐标和四面体网格系统,生成计算网格系统,再利用Fluent进行三维固液两相湍流的数值模拟。 数值模拟以固液两相流为介质,使用Fluent提供的多相流模型,压力修正使用SIMPLEC算法,通过对该模型设置不同的边界条件后,利用标准κ-ε湍流方程对离心叶轮内部流动情况进行数值模拟,计算了清水流场、浑水流场下颗粒直径相同和浓度不同、颗粒直径不同和浓度相同等四个不同工况下离心泵叶轮内部过流部件的三维固液多相湍流流场。根据四个不同工况下速度场和压力场分布的计算结果,初步分析了该叶轮的内部水力特性,比较了颗粒直径和泥沙浓度对计算结果的影响,分析浓度、速度、压力等流动参数在泵内的分布规律及其相互影响,分析了泵的磨损情况。 通过本课题的研究,对含沙水流中离心式水泵内部进行固液两相流场模拟,可以帮助探讨叶轮内部流动规律,总结叶轮及泵体的几何参数和介质对离心泵性能的影响,提出设计离心泵的一些改进措施并积累经验数据,为水力抗磨优化设计和制定防护措施提供依据和手段,为改善叶轮的性能和进一步深入研究水泵内部的固液两相流动机理提供一定的参考,对于解决含沙水流中水泵过流表面快速损坏问题具有重要的理论意义和实际应用价值。更多还原

【Abstract】 Centrifugal pumps are hydraulic machines which are widely used in pipeline transportation. The main invalid form is the abrasion of impeller. The solid-liquid two-phase flow within the pump is the quite attentive question by the pump designer, because the interior flow directly affects the performance of pump. The interior flow of pump is the quite complicated turbulent flow. It is affected not only by the circumrotation and the surface curvature of impeller, but also by the sandy materials, even has the backflow and disengaged flow. They are one of the rather complicated numerical calculations in the fluid engineering field.The subject has applied hydrokinetics to compare and analyze several kinds of theories and methods of turbulent flow. Based on the understanding the abrasion mechanism of centrifugal pump flow passage parts in high sandy flow, it has used normal κ - ε theory, and the mixture model has been selected. The subject has established the geometry model of the centrifugal pump, then the body-fitted coordinate systems and the tetrahedron grid systems are applied to establish grids system for calculate, finally fluent software is used to calculate the numerical simulation model about three-dimension solid-liquid two-phase turbulent flow.The subject selects YLB50-20 centrifugal pump. It has taken solid-liquid two-phase flow as the medium and applied multiphase model to calculate. The algorithm of SIMPLEC has used to correct of the pressure. After setting different boundary conditions, the physical models are computed in three-dimension solid-liquid two-phase turbulent flow of centrifugal pump in rinsing fluid field and muddy fluid field by choosing the different solid particle diameter and sandy volume fraction. Base on the calculative results in different typical work conditions, we can analyze the pump’s hydraulic performance and interior distribution rules and the interaction of some fluid parameters, such as consistence, velocity and pressure etc. We also can understand the fluid rules of particle and the abrasion mechanism through analyze the abrasion of the centrifugal pump. Using thenumerical simulation results we can summarize the affection of the geometric parameters and the medium to the pump’s performance. Thus, it is very significant to supply corrective measures to pump’s design and to find the factors affecting the pump’s performance and to supply reference for further study the solid-liquid two-phase turbulent flow of this kind of pump.The subject has studied the numerical simulation of the three-dimensional interior solid-liquid two-phase flow in the centrifugal pump and summarized some rules and the trajectory of solid particles. The work of this paper will be significantly helpful to afford new methods and experiences to design and to provide defensive measures to resolve and defend the abrasion of pump’s flow passage parts in high sandy flow. All of them are very significant to supply reference for further study centrifugal pump’s inner flow in theory and practice.更多还原