凝结水主调阀振荡分析及设计优化

Oscillation Analysis and Design Optimization of Condensate Main Control Valve

凝结水主调阀振荡是核电厂凝结水抽取系统的常见问题,对机组安全稳定运行产生严重不良影响。以凝结水主调阀系统工艺参数为研究对象,计算发现阀门在振荡区间的压差偏大,存在空化现象;振荡区间的噪声较设计值也明显偏大。建立CFD流体仿真模型分析计算,结果表明,在某一特定开度区间,凝结水主调阀的阀芯受力波动明显,导致阀门产生振荡。在此基础上,设计特征化打孔阀笼,改善流体和阀芯受力状态;增大气动执行机构的刚度,提高阀芯抵抗受力变化的能力。阀门改进后动作平稳,运行一个循环后阀内件无异常。优化措施有效抑制了阀门振荡问题的发生,有力保障机组安全稳定运行。

The oscillation of condensate main control valve is a common problem in condensate extraction system of nuclear power plant, which has serious adverse effect on the safety and stability of the unit. Take the actual operating parameters of the valve as the object of study, it is found that the pressure difference of the valve in the oscillation section is too large, and the noise in the oscillation section is obviously larger than the design value. Based on the analysis and calculation of CFD fluid simulation model, the results show that the main condensate control valve fluctuates obviously under a certain opening range, which leads to the oscillation of the valve. On this basis, the characteristic perforated valve cage is designed to improve the fluid state and the force applied to the valve plug, which increase the stiffness of pneumatic actuator and improve the ability of valve plug to resist the change of force. The condensate main control valve runs smoothly after the design improvement, and no abnormal problem is found inside of the valve trims after running a cycle. The optimization measures can effectively restrain the occurrence of valve oscillation and ensure the safe and stable operation of the unit.