CFD simulations of the Jack Rabbit ammonia and chlorine release experiments using FLACS

The Jack Rabbit test series consists of a series of experiments involving releases of ammonia and chlorine from pressurized tanks of 500 gallon nominal capacity. The scope of the tests was to provide experimental data that may be used to better understand the behavior of the flashing jet release, as well as to help validate atmospheric dispersion models that may be later used to predict the consequences of accidental releases.

The paper presents the results of blind test simulations of the Jack Rabbit experiments, performed using GexCon's computational fluid dynamics (CFD) tool, FLACS. The new two-phase model in FLACS is used for the simulations, which allows the model to predict the dispersion and deposition on the ground (rainout) of the aerosol droplets from the flashing jet release. The analysis of the simulation results is focused on evaluating the effect of the aerosol release and of the rainout pool evaporation on the evolution of the vapor cloud. The differences between chlorine and ammonia releases are also discussed and the effect of wind speed on the dispersion of the vapor cloud is evaluated parametrically.