中小型LNG运输船液货系统管道应力分析

Piping Stress Analysis of the Liquid Cargo System of Medium and Small Size LNG Carriers

LNG运输船的液货管系在装卸货时处于超低温工况,巨大的温差以及船舶复杂的工况会对管路产生应力。一旦管道设计布置不合理,会引起管路应力过大而造成损坏,导致安全隐患。中小型LNG运输船受布置空间限制,此问题尤其突出。详细阐述了LNG液货管道应力的安全评定方法和校核准则,并结合30000 m^3 C型独立液舱LNG运输船的特点,介绍利用CAESARⅡ软件进行管道应力分析的方法和实际应用。

The liquid cargo pipes of LNG carrier are in ultra-low temperature during the loading and unloading conditions.The large temperature difference and complex operation conditions may result in the pipe stress.Once the piping arrangement was unreasonable,the liquid cargo pipes would be damaged due to the excessive stress,especially for the medium and small size LNG carriers because of the limited space.The safety evaluation method and checking criterion was introduced in this article.Combined with the characteristics of a 30000 m3 type C independent tank LNG carrier,the method and practical case of the piping stress analysis by CAESAR II software was introduced.