A Three Dimensional, Finite Element Model for Simulating Heavier-Than-Air Gaseous Releases over Variable Terrain
Due to an increase of activities over recent years with the transport and storage of liquefied gaseous fuels (e.g. liquefied natural gas), it has become necessary to make careful assessments of the environmental risks associated with such operations. For example, the collision of a liquefied natural gas (LNG) carrying tanker can conceivably release a large amount of potentially flammable methane vapor into the atmosphere. Verified numerical models capable of predicting the gravitational spread and atmospheric dispersion processes following an LNG spill can provide qualitative and quantitative estimates of the motion of such a combustible vapor cloud. Solutions from these models can also be used as initial conditions for other models which treat the deflagation and detonation processes if accidental ignition of the NG/air mixture occurs. LLNL is involved in experimental and model verification studies for the Department of Energy with programs which encompass each aspect of the potential scenarios. Some of the major unresolved questions regarding LNG research are described in Mott et al. (1981). In this paper, we focus attention on the modeling of the vapor dispersion phase only.
KeywordsEddy Diffusivity Boussinesq Model Variable Terrain Hydrostatic Model Density Front
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