Numerical Analysis of Leakage Characteristics of Valve Sealing Structure
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摘要: 以核反应堆系统中的安全阀密封结构为研究对象，建立了基于多孔介质理论的密封结构粗糙表面三维模型，采用Darcy定律推导了密封结构泄漏率的计算公式，研究了粗糙度、自相关长度、密封比压对表面特征的影响，以及粗糙度、密封面接触宽度对泄漏率的影响。结果表明，粗糙度与密封性能并非是线性关系，仅以粗糙度作为密封性能的评价指标是有局限性的；在粗糙度一定的情况下，自相关长度也会对密封界面孔隙率、渗透率产生影响，从而影响安全阀的密封性能；密封比压减小导致接触高度增大，使得阀座阀瓣间的孔隙率迅速增大，造成密封结构的渗漏特性增强；粗糙度的增大使得泄漏率呈非线性增大趋势，密封面接触宽度的增加使泄漏率线性减小。Abstract: Taking the sealing structure of safety valve in nuclear reactor system as the research object, a three-dimensional rough surface model of sealing structure based on porous medium theory is established in this paper. The calculation formula of leakage rate of sealing structure is deduced by Darcy's law. The effects of roughness, autocorrelation length and sealing specific pressure on surface characteristics, as well as the effects of roughness and sealing surface contact width on leakage rate were studied. The results show that the relationship between the roughness and the sealing performance is not linear, and it is limited to only use the roughness as the evaluation index of the sealing performance. When the roughness is certain, the different autocorrelation length will also affect the porosity and permeability of the sealing interface, thus affecting the sealing performance of the safety valve. The decrease of sealing specific pressure leads to the increase of contact height, which makes the porosity between valve seat and disc increase rapidly, resulting in the enhancement of leakage characteristics of sealing structure. The increase of roughness makes the leakage rate increase nonlinearly, and the increase of sealing surface contact width makes the leakage rate decrease linearly.
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Key words:
- Sealing /
- Valve /
- Rough surface /
- Leakage rate
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图 1 接触界面微孔流道示意图
Figure 1. Schematic Diagram of Microporous Channel at Contact Interface
图 6 自相关长度对表面形貌特征的影响
Figure 6. Effect of Autocorrelation Length on Surface Topography Characteristics
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