高温高压离心泵三维湍流数值模拟及流动特性研究

发布时间：2018-06-26 09:53

本文选题：高温高压离心泵 + 数值模拟　；参考：《清华大学》2011年硕士论文

【摘要】：在核电站中，蒸汽发生器的主要功能是将核岛反应堆产生的热量转换为常规岛汽轮机所需的蒸汽热量，蒸汽发生器通过主给水泵进行给水，主给水泵运行工况为高温高压，目前对高温高压泵内部的流场分析较少，因此对高温高压泵进行内部流动特性研究有其必要的意义。本文以高温高压离心泵为研究对象，建立了离心泵从进口到出口的全流道三维几何模型，对形状规则的离心泵进口管区域采用六面体结构化网格，其余流体区域如叶轮、导叶、泵壳等，采用网格适应性较强的非结构化网格进行划分，动静面的流动信息交换通过应用快速滑移网格技术来完成。通过湍流模型的数值模拟结果与实验数值的比较，本文选择RNGk-ε湍流模型对离心泵进行定常与非定常三维全流道湍流数值计算，分析高温高压离心泵内部流动特性。在进行定常湍流计算时，分析平衡孔对离心泵的性能的影响，研究其降低轴向水推力的机理。在高温高压的条件下，模拟动叶轮与静止导叶之间的仿生蜂巢形密封环内的流体流动机理。在完成离心泵三维非定常湍流计算的基础上，本文分析了设计工况及偏流量工况下，主要压力脉动的产生机理、压力脉动的传播规律、脉动源的位置及压力脉动的振幅特性。通过对高温高压离心泵泵壳上布置测点来分析压力脉动的幅值对泵壳安全性的影响，结果表明位于泵壳壁面上测点的压力脉动的幅值很小，，从而判断对泵壳的安全性能的影响不大。由于高温高压离心泵的泵壳设计成类似球形结构，其水力损失较大，本文对泵壳内的水力损失及流动状态做具体的分析，发现泵壳内的流体流动状态非常紊乱，并且含有大量的旋涡，从导叶流出的流体很大一部分在泵壳内经多次回流才能流出，并且在靠近出水管类似隔舌处，出现很大一块在驻点区域，同样造成了较大的冲击损失。
[Abstract]:In nuclear power plant, the main function of steam generator is to convert the heat produced by nuclear island reactor into the steam heat required by conventional island steam turbine. The steam generator feeds water through the main feed pump, and the main feed pump operates under high temperature and high pressure. At present, the flow field analysis of high temperature and high pressure pump is less, so it is necessary to study the internal flow characteristics of high temperature high pressure pump. Taking the high temperature and high pressure centrifugal pump as the research object, the three-dimensional geometry model of the whole flow channel of the centrifugal pump from the inlet to the outlet is established. The hexahedron structured grid is used for the inlet tube of the centrifugal pump with regular shape, and the other fluid regions such as impeller and guide vane are used. The pump shell is divided into unstructured meshes with strong mesh adaptability. The flow information exchange of dynamic and static surfaces is accomplished by using rapid sliding mesh technology. By comparing the numerical simulation results of the turbulent model with the experimental data, RNGk- 蔚 turbulence model is selected to calculate the steady and unsteady three-dimensional turbulent flow of the centrifugal pump, and the internal flow characteristics of the high temperature and high pressure centrifugal pump are analyzed. In the calculation of steady turbulent flow, the influence of balance hole on the performance of centrifugal pump is analyzed, and the mechanism of reducing axial water thrust is studied. Under the condition of high temperature and high pressure, the fluid flow mechanism in the bionic honeycomb seal ring between the moving impeller and the stationary guide vane is simulated. On the basis of the three-dimensional unsteady turbulent flow calculation of centrifugal pump, the mechanism of the main pressure pulsation, the propagation law of the pressure pulsation, the position of the pulsating source and the amplitude characteristics of the pressure pulsation under the design condition and the partial flow condition are analyzed in this paper. The influence of the amplitude of pressure pulsation on the safety of pump shell is analyzed by placing measuring points on the shell of high temperature and high pressure centrifugal pump. The results show that the amplitude of pressure pulsation at the measuring point on the wall of pump shell is very small. As a result, the influence on the safety performance of pump case is not obvious. Because the pump case of high temperature and high pressure centrifugal pump is designed as a spherical structure, its hydraulic loss is large. This paper makes a concrete analysis of the hydraulic loss and flow state in the pump shell, and finds that the fluid flow state in the pump shell is very disordered. And there are a large number of vortex, a large part of the fluid flowing out from the guide vane can flow out after several reflux in the pump shell, and near the outlet pipe similar to the tongue, there is a large area in the stationary point, which also caused a large impact loss.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311

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