Numerical Simulation of Temperature Distribution Under Small Hole Leakage at the Inner Wall of LNG Tank

Author of the article:Zhang Na, Li Zhaoci, Guo Zhichao

Author's Workplace：National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum, Beijing, 102200, China

Key Words：LNG tank; Small hole leakage; Temperature field; Numerical simulation

Abstract：The LNG storage tank is the core equipment of the receiving station,and the inner wall leakage causes the destruction of the insulation layer and the outer wall.This paper is aimed at the small hole leakage at the inner wall of bimetal full containment LNG tank.By setting the thermal boundary conditions and the physical properties of the insulation layer, the number of inner wall grids is divided and the steady temperature distribution of the inner tank wall is simulated.By analyzing the convective heat transfer at the leak point, a two-dimensional unsteady seepage equation is established to calculate the flow field distribution of the leaking liquid in the insulation layer of the tank.The obtained velocity distribution is added as a convection diffusion term to the two-dimensional unsteady convective heat transfer equationso as to complete the coupling of velocity field and temperature field, and obtain the temperature distribution of insulation layer of the inner wall.When leakage occurs to LNG inner tank, the leaking liquid first gathered downward,and the elastic felt near the leak source first cooled to the LNG temperature.And the temperature gradient here is large.Then, it gradually penetrates into the expanded perlite insulation layer along the bottom of the tank,which provides theoretical basis and scientific guidance for the rescue and accident analysis of the inner tank leakage, so as to minimize the hazard caused by the leakage.