液化天然气超低温球阀阀座密封性能分析

Study on Sealing Performance of Ultra-Low Temperature Ball Valve Seat for Liquefied Nature Gas

超低温球阀被广泛应用于液化天然气(LNG)系统中。以LNG球阀为分析对象,通过有限元计算获取球阀工作时的温度、位移、应力和密封情况,重点对比分析了常温与低温下泛塞与密封圈的接触比压及有效密封区域。结果表明,低温工况造成部件急剧冷缩变形,同时内部温度的不均匀分布也会造成接触装配部件间的冷缩量差异较大,进而对应力和接触压力分布造成影响,导致低温下有效密封区域缩小,甚至产生密封失效。研究成果可为超低温球阀的密封设计及性能评估提供参考。

Ultra-low temperature ball valves are widely used in the pipeline systems of liquefied natural gas.Taking the ball valve as analysis objective,the temperature,displacement,stress and sealing were calculated using finite element simulation.The specific contact pressure and effective sealing area of the variseals and the sealing rings at normal temperature and low temperature were emphatically analyzed.The results showed that low temperature conditions would cause cold shrinkage deformation of components,and the uneven temperature distribution within components would also result in great difference of cold shrinkage between contact components.Therefore,the distribution of stress and contact pressure would be affected,leading to the reduction of effective sealing area at low temperature and even sealing failure.The research results can provide reference for design and performance assessment of sealing in ultra-low temperature ball valves.