(89c) Modeling the Spreading of Large LNG Spills on Water

This paper reviews and summarizes the models that are currently used to describe the evolution of a pool of spilled liquid that is spreading on water. In particular, the paper focuses on the spread of Liquid Natural Gas (LNG) on water in the event of a large spill, which is a critical element in the risk and safety analyses for LNG terminals. This paper first revisits the history of the early experimental work and the models that were derived from it, identifying their contributions and limitations. The models calculate the local height and speed evolution of the pool, along with the trajectory of its front. This paper then presents a time-dependent one-dimensional framework that models the transient behavior of a spill that is then used to compare the different model assumptions for large circular and semi-circular pools. The paper uses the GASP model developed by Webber as a baseline to describe the impact of different friction models between the spreading pool and the water. Friction becomes an important effect for very large spills, but it has garnered limited attention so far largely due to the design of early experiments, in which friction was not important compared to other effects. This paper demonstrates the importance of friction, the lack of validation of the current friction models with experiments and the fact that current models do not capture the expected variation in friction under the footprint of the spill associated with thermal and flow variations between the source and the leading edge of the spill.