核电弹簧式蒸汽安全阀关键技术基础研究

发布时间：2018-03-17 05:19

本文选题：核电安全阀　切入点：热态试验　出处：《华东理工大学》2017年博士论文　论文类型：学位论文

【摘要】：作为保障核电站安全运行的最重要的安全附件之一的安全阀,在核电站的设计和运行过程中起着至关重要的作用。蒸汽安全阀在高温高压、大开度、临界流及地震工况下的动态特性模拟是优化安全阀设计、提高安全阀运行可靠性的重要手段及方法,而国内外在这方面的研究非常缺乏,造成了目前核电蒸汽安全阀研制周期长、成本高等问题。此外,安全阀在动作过程中常会出现运动部件的表面损伤,影响安全阀的动作性能。针对以上问题,本文在安全阀热态试验、动态模拟及表面强化三个方面展开了研究,主要研究内容与创新成果如下:1、设计并建成了国内首套符合国际标准的安全阀热态试验装置,进行了高温高压、大口径核电弹簧式蒸汽安全阀的热态试验。采用了网格预变形、动网格、流域分块、外接虚拟大容器等模拟技术,并利用二阶微分方程对阀瓣的动态特性进行了编译,精确地计算了阀瓣的运动状态,实现了高温高压、大口径弹簧式蒸汽安全阀的动态模拟。模拟结果与试验结果吻合良好。对于高温高压蒸汽安全阀,排量随着帘面积与喉部面积比值的增加而上升,在该比值达到1.18时排量达到最大值。流场中的高马赫数区域随着安全阀开高的改变而发生变化,在稳定排放时有三个高马赫数区域。使用压缩空气为介质时,安全阀的回座压力比使用蒸汽为介质时要高。蒸汽过热度从0℃变化到100℃时对高温高压安全阀动作性能的影响可以忽略。回座压力随着上调节圈的位置改变近乎成线性变化,受下调节圈位置影响微小。安全阀额定开高与喉径的比值在0.25和0.35时比在0.3时有着更高的启闭压差。减少弹簧刚度可显著降低回座压力但对安全阀的开启时间影响不大。2、对带有背压腔结构的核电主蒸汽安全阀进行了动态模拟,模拟结果得到相关试验验证。发现背压腔结构对安全阀的动作性能有较大的影响。在安全阀开启阶段,背压腔内压力上升滞后,对安全阀开启过程影响微弱。在回座阶段背压腔内蒸汽压力下降滞后,有助于安全阀快速回座。背压腔中调节套的位置对启闭压差影响较大,在E值(调节套上端到背压套盖上端的距离)从35mm增加到62mm的过程中,E值每增加1mm,启闭压差就线性地增加0.163%。采用响应面法对上调节圈、下调节圈、调节套和调节螺钉这四个调节机构对主蒸汽安全阀启闭压差的调节规律进行了研究,发现上调节圈的位置对启闭压差影响最大,调节套的位置对启闭压差影响次之,调节螺钉和下调节圈位置对启闭压差影响最小,这四个机构之间的交互作用对启闭压差的影响较弱。3、建立了弹簧式安全阀流固耦合动态模拟方法,通过加载正弦波初步探索了纵向地震波对安全阀动作性能的影响。结果发现,增大数值阻尼系数,弹簧被压缩之后的振荡幅度减小,有利于安全阀的稳定排放。在竖直方向正弦波的作用下,安全阀会出现颤振,回座压力受正弦波的相位和频率影响。4、为避免冲蚀损伤和安全阀运动部件之间的擦伤劣化安全阀的动作性能,研制了WC/Ni柔性布复合涂层。发现304不锈钢基体与复合涂层之间形成了冶金结合,Ni扩散进入WC颗粒提高了 WC颗粒与Ni基的结合力。实验结果表明WC颗粒的添加对涂层的耐磨性能影响显著,WC颗粒含量为59.80 wt.%的WC/Ni复合涂层的体积磨损率仅为304不锈钢基体的1/328。两体磨料磨损、三体磨料磨损和疲劳磨损三种磨损机制都存在于WC/Ni柔性布复合涂层的摩擦磨损过程中。在30°冲蚀时,Ni+59.80wt.%WC的复合涂层的耐冲蚀性能为304不锈钢基体的1.4倍。30°冲蚀时,涂层的失效机理主要为冲蚀颗粒对涂层的微观切削和微观犁沟效应,90°冲蚀时,涂层的失效机理主要为冲蚀颗粒对涂层的锤击效应。
[Abstract]:As a safety valve is one of the most important safety accessories to ensure the safe operation of nuclear power plants, plays a crucial role in the design and operation of the nuclear power plant. The steam safety valve in the high temperature and high pressure, large opening, dynamic characteristics and seismic critical flow condition is simulated to optimize safety valve design, and an important means to improve operation method of the reliability of the safety valve, and domestic and international research in this area is very lacking, resulting in the current development of nuclear power steam safety valve long cycle and high cost. In addition, the surface damage of safety valve moving parts in the course of action often, affect the performance of safety valve. To solve the above problems, based on the thermal safety valve test, dynamic simulation and surface strengthening of three aspects of the research, the main research contents and achievements are as follows: 1, the safety valve is designed and built the first domestic heat in line with international standards State test device of high temperature and high pressure, the thermal test of large diameter spring type nuclear power steam safety valves. The mesh deformation, dynamic mesh, block, external tank virtual simulation technology, and using the two order differential equation on the dynamic characteristics of the valve are compiled, accurate calculation the motion state of the valve, the high temperature and high pressure, the dynamic simulation of large caliber spring type steam safety valves. The simulation results are in good agreement with the experimental results. The high temperature and high pressure steam safety valve, the displacement with the curtain area and the increase of the ratio of the throat area is on the rise, when the ratio reached 1.18 when the displacement field reaches the maximum value. The high Maher number with the safety valve opening changes, there are three high Maher number in the region. Stable discharge using compressed air as medium, pressure relief valve in the back seat than the use of steam as a medium to high. Steam superheat from 0 degrees to 100 degrees of change of high temperature and high pressure safety valve performance can be ignored. With the back seat pressure adjusting ring position change almost linearly, by adjusting ring position effect small. Safety valve rated high ratio and throat diameter in 0.25 and 0.35 when opening and closing pressure the difference is higher than in 0.3. With reduced spring stiffness can significantly reduce the back seat pressure but the opening time of.2 had no effect on the safety valve of nuclear main steam safety valve with back cavity were simulated, the simulation results of related experiments. That has great influence performance of back pressure cavity the structure of the safety valve. In the stage of opening the safety valve, the back pressure chamber pressure rise to the valve opening process lag, weak effect. In the back seat back pressure cavity stage steam pressure drop behind, contribute to the rapid safety valve back seat back pressure chamber. In the position of the regulating sleeve has great influence on the opening and closing pressure, the E value (the regulating sleeve top to the upper end of the cover pressure distance) increased from 35mm to 62mm in the process of E value for each additional 1mm, opening and closing pressure is linearly increased 0.163%. by response surface method on the adjustment ring, adjusting ring regulation, closing pressure of main steam safety valve of the regulating sleeve and the adjusting screw four adjusting mechanism, the adjustment ring position that the greatest impact on the opening and closing pressure, adjust the set position for opening and closing pressure effect, adjusting screws and adjust the position of the ring opening close the pressure difference between the four institutions is minimum, the interaction of the weak.3 effect of the opening and closing pressure, established a solid coupling dynamic simulation method of spring type safety valve, the load and study the influence of longitudinal seismic wave on the performance of safety valve. It is found that the increase of resistance value The damping coefficient, the oscillation amplitude after compressed spring decreases, a stable discharge to the safety valve. In the vertical direction under the effect of sine wave, the safety valve will appear flutter, back seat pressure by the phase and frequency of sine wave effect of.4, the performance of safety valve in order to avoid the deterioration of erosion damage and abrasion between the moving parts of the safety valve the development of the WC/Ni flexible cloth composite coating. It is found that the metallurgical bonding is formed between the 304 stainless steel substrate and the composite coating, the diffusion of Ni into WC particles improves the binding force of WC particles and Ni matrix. The experimental results show that the effect of the addition of WC particles on wear resistance of the coating significantly, the content of WC particles is 59.80 WC/Ni composite coating wt.% the volume of the wear rate is only 304 stainless steel 1/328. two body abrasive wear, abrasive wear and fatigue wear of three kinds of wear mechanisms are found in WC/Ni flexible cloth composite coating, friction and wear In the process. In 30 degrees of erosion, Ni+59.80wt.%WC composite coating erosion resistance of 304 stainless steel 1.4 times.30 DEG erosion, the failure mechanism of the coatings mainly for erosion particles on the coating of micro cutting and micro ploughing. 90 degrees of erosion, the main failure mechanism of coated particles on coating for erosion hammer effect.

【学位授予单位】：华东理工大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM623

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