高压分离器双锥环密封失效的数值模拟

Numerical Failure Simulation of Double-cone Sealing of a High Pressure Separator

针对国内某厂一台双锥环密封的高压分离器在非正常操作中出现的泄漏失效，采用ＰＡＦＥＣ大型有限元程序进行了模拟全操作过程的ＦＥＭ分析。在按实际建立的力学与传热计算模型上，数值模拟了包括预热、正常操作和急冷等工况下典型节点的温度－时间变化，垫片应力－介质内压变化的关系，同时探讨了双锥环内侧与端盖圆柱面之间的间隙与密封性能的关系。计算结果表明，双锥环密封结构的温度改变导致垫片应力的改变是密封失效的重要原因，适当加大间隙值可以提高双锥环密封对温度、压力波动的适应性。

The most researches of doublecone sealing were focused on the analysis of local- positions of its sealing structures and the static process, even at the high temperatures. However most failures of the sealing structures do not occur normal working conditions but occur when the temperature fluctuates. In this paper, the failure of a doublecone sealed high pressure separator in a domestic plant is researched by a FEM analysis of the simulation of the whole operation process at the irregular working conditions. Based on the established calculating mode of practical mechanics and heat transfer, the Tt relationship of typical node and the stresses of gasketinternal pressure of medium relationship under the working conditions at preheating, normal operation and emergency cooling are simulated numerically. The effects on the sealing properties of gaps between the inside of doublecone ring and the cylindrical side of the cover is discussed. The results show that the important reason of the sealing failure is due to the change of the gasket stress which is caused by the temperature alternation of doublecone sealing structures. To increase the gap in certain degree can make the doublecone sealing more flexible to the fluctuation of temperature and pressure.