超（超）临界蒸汽疏水阀空化与热流固耦合研究

发布时间：2019-06-04 21:40

【摘要】：阀门作为超(超)临界火电机组的关键配套产品,是保证机组安全、经济运行的重要设备之一。我国常规火电90%高端阀门长期依赖进口,而传统的物理样机试验、静态经验公式计算设计等方法根本不能满足高参数阀门的设计要求。随着计算机辅助设计技术及计算机性能的迅速发展,用数值模拟来解决高温高压差类阀门的主要问题成为可能。运用数值模拟的方法可对实验难以测量的参数及静态计算与实验未考虑的问题进行预测,不需要大量的实验,能显著降低阀门的生产成本、缩短开发周期、优化阀门结构性能。超(超)临界蒸汽疏水阀作为长期进口高端阀门之一,难以实现国产化的最主要问题在于：需要深入研究疏水阀的内部空化流动特性：对防空化元件进行深入研究,有效抑制空化的发生；解决阀体材料的选择与强度问题。本文针对该问题进行了以下研究,为其它高温高压差类阀门的设计提供参考。 1)对超(超)临界疏水阀数值模拟理论进行研究,建立三维模型,对阀内流动进行空化流数值模拟,着重研究阀内空化流动特性,获取阀内压力、速度和液－汽体积分布等物理量的分布图,预测空化的发生。模拟研究不同开度、压力入口、压力出口、密封面角度对空化发生的程度、区域及范围的影响。 2)从理论上对多级降压套筒的级数、开孔面积、级间间隙、厚度进行研究,并采用理论计算与数值模拟相结合的方法对控制多级节流过程的阀内多级套筒防空化节流元件各参数如孔径大小、级间间隙、开孔的类型、级间导流槽结构等因素对阀内流场的影响,尤其是对空化流动的影响进行深入研究。 3)建立疏水阀主要过流承压部件与流体介质耦合的几何模型,利用ANYSY Workbench平台进行热流固耦合数值分析。着重研究工作状态下疏水阀主要部件的温度场、热应力及变形情况,并研究关闭状态疏水阀的强度问题。
[Abstract]:Valve, as the key supporting product of super (super) critical thermal power unit, is one of the important equipment to ensure the safety and economic operation of the unit. 90% of the conventional thermal power high-end valves in China rely on import for a long time, but the traditional physical prototype test and static empirical formula calculation and design methods can not meet the design requirements of high-parameter valves. With the rapid development of computer aided design technology and computer performance, it is possible to solve the main problems of high temperature and high pressure differential valves by numerical simulation. The numerical simulation method can be used to predict the parameters that are difficult to measure in the experiment and the static calculation and the problems not considered in the experiment. Without a large number of experiments, the production cost of the valve can be significantly reduced, the development cycle can be shortened, and the valve structure and performance can be optimized. As one of the high-end valves imported for a long time, the most important problem that it is difficult to realize localization is that the internal cavitation flow characteristics of the drain valve need to be deeply studied: the anti-cavitation elements are deeply studied. Effectively inhibit the occurrence of cavitation; Solve the problem of material selection and strength of valve body. In this paper, the following research is carried out to provide reference for the design of other high temperature and high pressure differential valves. The main contents are as follows: 1) the numerical simulation theory of super critical hydrophobic valve is studied, and a three-dimensional model is established to simulate the cavitation flow in the valve, with emphasis on the cavitation flow characteristics in the valve and the pressure in the valve. The distribution maps of physical quantities such as velocity and liquid-vapor volume distribution predict the occurrence of cavitation. The effects of different opening, pressure inlet, pressure outlet and sealing surface angle on the degree, area and range of cavitation are simulated and studied. 2) the series, opening area, interstage gap and thickness of the multistage pressure reduction sleeve are studied theoretically. The parameters of multistage sleeve anti-cavitation throttling element, such as aperture size, interstage gap and opening type, are studied by means of theoretical calculation and numerical simulation. The influence of interstage diversion slot structure on the flow field in the valve, especially on the cavitation flow, is studied in detail. 3) the geometric model of the coupling between the main overcurrent pressure components of the hydrophobic valve and the fluid medium is established, and the numerical analysis of the thermal-fluid-solid coupling is carried out by using the ANYSY Workbench platform. The temperature field, thermal stress and deformation of the main components of the hydrophobic valve under working condition are studied, and the strength of the hydrophobic valve in the closed state is also studied.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH134;TM621

【参考文献】