Computational study of LNG evaporation and heat diffusion through a LNG cargo tank membrane

• Published in: Ocean engineering 2015-09, Vol.106, p.77-86
• Main Authors: Lee, Jang Hyun, Kim, Yoon Jo, Hwang, Seyun
• Format: Article
• Language: English
• Subjects: BOR (boil-off-ratio); Computational fluid dynamics; Computational methods; Computer simulation; Diffusion; Evaporation; Insulation; LNG cargo containment; LNG leakage; Marine; Mathematical models; Membranes; Multiphase flow; Porous media; Seepage; Spots
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2015.06.045

The seepage of the cryogenic LNG through the cracks in membrane insulation may result in cold spots within the hull structures of LNG vessels. At the cold spot, the hull structure will be crystalized and brittle. Also, the loss of LNG containments may lead to a potentially significant hazard. The estimation of the temperature distribution along the insulation panel and the heat diffusion speed through the insulation materials are crucial to assess the safety of LNG vessels. The prediction of the flow and thermal behaviors of the leaked LNG requires complex multiphase flow numerical simulation. The CFD (computational fluid dynamics) model is proposed to simulate the diffusion behavior and the heat transfer characteristics of leaked LNG including the liquid-to-gas phase change through porous structure. The CFD model considers phase change, gas–liquid reactions in the porous media and the accompanied rates of heat transfer. It also considers the geometry of NO96 membrane storage facilities with glass wool and plywood. In the numerical simulation, the LNG pool spreading, heat diffusion, and the evaporation are investigated. The simulation indicates that the predicted speed of seepage is too high to evaporate the LNG after the leakage. •The hydraulic and thermal diffusion behaviors of leaked LNG through modified NO96.•A referential CFD setup and numerical scheme for LNG spill and leakage prediction.•The diffusion speed through the insulation box was very fast.•The evaporation did not vigorously take place.•The glass wool was not suitable to satisfactorily delay the leaked flow.