核电安全阀内临界流和气穴流的三维定常数值模拟
发布时间：2018-11-20 15:18
【摘要】：安全阀是承压系统中重要的安全附件之一。本文使用计算流体力学软件CFx研究核电安全阀内的过热蒸汽临界流和过冷水气穴流,所得到的结论对核电安全阀结构设计和优化具有借鉴意义。本文的主要工作如下： (1)在蒸汽安全阀出口处接一圆柱形容器获得计算用几何模型,模拟了不同开高、入口压力和下调节圈位置时过热蒸汽的临界流场,以及以理想水蒸气作流体介质时的临界流场。通过分析发现：安全阀内出现临界流时,音速面出现在上下调节圈组成的环形区域内,而不是在喉径横截面上；该音速面的范围随着入口压力、下调节圈高度的增大而增大；临界流抑制了阀门的泄放能力,排量系数随着开高增大出现震荡,随着音速面范围的增大而减小：过热蒸汽物性对速度场模拟结果影响不大,对温度场模拟结果有严重影响。 (2)使用蒸汽安全阀作为气穴流模拟的几何模型,研究了恒定物性的过冷水的流场分布情况。通过模拟和分析不同结构、出口压力和入口流速的气穴流场发现：气穴主要发生上下调节圈组成的环形区域内；当气穴发生在阀瓣和反冲盘受力面与密封面组成的环形区域内时,气穴流严重消弱安全阀动作性能；气穴数量随着出口压力和开高的增大而减小,随着入口流速的增大而增大。
[Abstract]:Safety valve is one of the important safety accessories in the pressure system. In this paper, the superheated steam critical flow and supercooled cavitation flow in the nuclear power safety valve are studied by using the computational fluid dynamics software CFx. The conclusions obtained are useful for the design and optimization of the nuclear power safety valve structure. The main work of this paper is as follows: (1) the critical flow field of superheated steam at different opening heights, inlet pressures and the position of the lower regulating ring is simulated by using a geometric model for the calculation of a cylindrical vessel at the outlet of the steam safety valve. And the critical flow field when ideal water vapor is used as fluid medium. It is found that when the critical flow occurs in the safety valve, the sonic surface appears in the annular region composed of the upper and lower regulating rings rather than on the throat cross section, and the range of the sonic plane increases with the inlet pressure and the height of the lower regulating ring. The critical flow inhibits the discharge capacity of the valve, and the displacement coefficient oscillates with the increase of the opening height and decreases with the increase of the sonic surface. The physical properties of superheated steam have little effect on the simulation results of the velocity field, but have serious influence on the simulation results of the temperature field. (2) using steam relief valve as the geometric model of cavitation flow simulation, the flow field distribution of supercooled water with constant physical properties is studied. By simulating and analyzing the cavitation flow field with different structures, outlet pressure and inlet velocity, it is found that the cavitation mainly occurs in the annular region composed of upper and lower regulating circles; When the cavitation occurs in the annular region composed of the disc and the recoil disc, the cavitation flow seriously weakens the performance of the relief valve, and the number of the cavitation decreases with the increase of the outlet pressure and opening height, and increases with the increase of the inlet velocity.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH134
本文编号：2345256
[Abstract]:Safety valve is one of the important safety accessories in the pressure system. In this paper, the superheated steam critical flow and supercooled cavitation flow in the nuclear power safety valve are studied by using the computational fluid dynamics software CFx. The conclusions obtained are useful for the design and optimization of the nuclear power safety valve structure. The main work of this paper is as follows: (1) the critical flow field of superheated steam at different opening heights, inlet pressures and the position of the lower regulating ring is simulated by using a geometric model for the calculation of a cylindrical vessel at the outlet of the steam safety valve. And the critical flow field when ideal water vapor is used as fluid medium. It is found that when the critical flow occurs in the safety valve, the sonic surface appears in the annular region composed of the upper and lower regulating rings rather than on the throat cross section, and the range of the sonic plane increases with the inlet pressure and the height of the lower regulating ring. The critical flow inhibits the discharge capacity of the valve, and the displacement coefficient oscillates with the increase of the opening height and decreases with the increase of the sonic surface. The physical properties of superheated steam have little effect on the simulation results of the velocity field, but have serious influence on the simulation results of the temperature field. (2) using steam relief valve as the geometric model of cavitation flow simulation, the flow field distribution of supercooled water with constant physical properties is studied. By simulating and analyzing the cavitation flow field with different structures, outlet pressure and inlet velocity, it is found that the cavitation mainly occurs in the annular region composed of upper and lower regulating circles; When the cavitation occurs in the annular region composed of the disc and the recoil disc, the cavitation flow seriously weakens the performance of the relief valve, and the number of the cavitation decreases with the increase of the outlet pressure and opening height, and increases with the increase of the inlet velocity.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH134
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