(88d) Validation of a CFD Model for Vapor Dispersion from LNG Spills into an Impoundment

Recent discussions on the fate of LNG spills into impoundments have led to the conclusion that the commonly used combination of SOURCE5 and DEGADIS to predict the flammable vapor dispersion distances is not physically accurate, as it does not account for air entrainment into the evaporating gas and it does not allow for heating of the LNG vapor cloud within the impoundment. An alternative approach to predict the flammable vapor dispersion distance is to use a computational fluid dynamics (CFD) model. CFD codes can take into account the physical phenomena that govern the fate of LNG spills into impoundments, such as air entrainment and ground-to-vapor heat transfer. Before a CFD code can be proposed as an alternate method for the prediction of flammable vapor cloud distances, it has to be validated with proper experimental data. This paper describes the validation effort of Fluent, a widely-used commercial CFD code, for the prediction of flammable vapor cloud dispersion. Fluent was used to simulate the ?Falcon? series of LNG spill tests, which is the only series of tests performed specifically to address the effects of vapor barriers and building obstructions on the vapor cloud dispersion. A comparison of CFD predictions and experimental data will be made, both graphically and by means of statistical performance measures.