基于流固耦合的LNG储罐进料管道应力分析

Study on Liquefied Natural Gas Tank Filling Nozzle Stress based on Fluid-solid Coupling

提出基于流固耦合的LNG储罐进料管道应力分析方法,并研究进料过程中管道最大应力的变化规律。根据多相流理论对LNG储罐进料过程及进料稳定后管道中的流场进行CFD模拟,分析流场中LNG体积分数、流速及液体压力等参数的变化情况。基于流固耦合方法计算管道中LNG流动对其产生的应力,并分析管道中应力分布规律与流场参数之间的关系。计算了LNG进料达到稳态前不同时刻点管道的应力,并研究最大应力变化规律,结果表明,LNG进料过程中管道的应力变化较为复杂,最大等效应力出现先升、后降、再升、最后稳定的变化趋势,且最大应力出现的位置随进料时间发生变化。LNG进料过程中可能出现水击现象,水击会导致管道某一位置出现较大应力,设计时应给予考虑。

The method for liquefied natural gas（LNG）tank filling nozzle stress analysis through fluid-solid coupling was proposed,and the rule of the stress variation with time was studied.The computational fluid dynamics simulation of LNG flowing process in the filling nozzle was carried out through multiphase flow theory.The parameters of volume fraction,velocity and pressure in the flow field were analyzed.The stress due to hydraulic pressure in nozzle was calculated by fluid-solid coupling and FEA.The relation between the stress distribution and fluid parameters was investigated.Finally,the stress in nozzle at each time before the fluid flow stabilization was calculated,and the variation tendency was studied.The results show that the stress in nozzle varies complexly in the process of LNG filling,the maximum equivalent stress presents the variation tendency of ascending,descending,and ascending again and keeping steady at last,and the location of the maximum equivalent stress varies with time.The phenomena of water hammer may appear,and water hammer will cause a larger stress at some place,which should be considered in the design stage.