核二级波纹管截止阀强度刚度及疲劳可靠性研究

发布时间：2019-01-06 09:43

【摘要】：在低碳经济背景下,核能将成为最具潜力的新能源之一,核级阀门作为核电站各系统的连接枢纽,是核电站可靠运行的基本保障。在核电站正常运行过程中,由于核级阀门自身可靠性不足等问题,其每年的维修费用就占总维修金额的一半以上。针对核级阀门可靠性检验与评价不足的难点问题,如试验条件的局限性、试验过程的复杂性,以及疲劳强度失效的危险性等问题,本文以典型参数下的核二级波纹管截止阀为载体,对其结构的强度和疲劳可靠性进行以下分析。(1)根据核级阀门的高可靠性要求,对核级阀门的标准体系和材料进行了阐述,依据相关标准对核二级波纹管截止阀阀体进行强度计算及壁厚校核;同时,对截止阀在拉伸、挤压、弯曲外载荷作用以及地震载荷作用下的结构强度进行了有限元分析,确保其在分析设计过程中的有效性。(2)基于应力-强度干涉理论,对截止阀用波纹管进行了可靠度模型的建立;运用非线性相关理论,对核二级波纹管截止阀用的两层波纹管在只承受外压载荷、只承受拉压载荷和承受外压与拉压载荷的工况下进行分析,分别研究了波纹管的间隙、拉压位移载荷对波纹管结构强度和疲劳寿命的影响,对截止阀用双层波纹管的制造、使用及疲劳寿命的提高具有一定的指导作用。(3)基于热流固耦合数学方程和边界条件的相关理论,对全开状态下的核二级波纹管截止阀阀体进行了瞬态温度场和瞬态热冲击分析,对核级阀门如何提高疲劳寿命以及如何有效降低承压热冲击的危害提供了一定的指导意义。
[Abstract]:In the context of low carbon economy, nuclear energy will become one of the most potential new energy sources. Nuclear valve, as the connection hub of nuclear power plant systems, is the basic guarantee for the reliable operation of nuclear power plant. In the normal operation of nuclear power plant, due to the lack of reliability of nuclear valve itself, the annual maintenance cost accounts for more than half of the total maintenance amount. Aiming at the difficult problems of nuclear valve reliability inspection and evaluation, such as the limitation of test conditions, the complexity of test process, and the danger of fatigue strength failure, etc. In this paper, the structure strength and fatigue reliability of nuclear two-stage bellows stop valve under typical parameters are analyzed as follows. (1) according to the requirements of high reliability of nuclear valve, The standard system and material of nuclear grade valve are expounded, and the strength calculation and wall thickness check of the valve body of nuclear two-stage bellows are carried out according to the relevant standards. At the same time, the structural strength of the globe valve under the action of tension, extrusion, bending external load and seismic load is analyzed by finite element method to ensure its validity in the process of analysis and design. (2) based on the stress-strength interference theory, The reliability model of the corrugated pipe used in the globe valve is established. By using nonlinear correlation theory, the two-layer bellows used in nuclear two-stage bellows are analyzed under the condition of only withstanding external pressure load, only withstanding tension and compression load, and bearing external pressure and tension compression load. The clearance of bellows is studied respectively. The influence of tension and pressure displacement load on the structural strength and fatigue life of bellows, and the manufacture of double-layer bellows for globe valves, Application and fatigue life increase have certain guiding function. (3) based on the heat fluid-solid coupling mathematical equation and the related theory of boundary conditions, The transient temperature field and transient thermal shock analysis of the nuclear two-stage bellows valve body under the fully open condition are carried out, which provides certain guiding significance for how to improve the fatigue life of the nuclear grade valve and how to effectively reduce the harm of the pressure heat shock.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM623

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