FEM3 Modeling of Ammonia and Hydrofluoric Acid Dispersion

摘要

FEM3 is a three-dimensional computer model that was designed to simulate the atmospheric dispersion of heavier-than-air gas releases. Recently a phase-change submodel based on local thermodynamic equilibrium has been implemented to treat vapor-liquid transition of the dispersed material. A preliminary evaluation of the phase-change submodel was performed by using data obtained from two recently conducted series of field experiments, namely, the pressurized ammonia spills conducted by LLNL and the anhydrous hydrofluoric acid dispersion experiments conducted by Amoco Oil Company and LLNL. FEM3 results compare reasonably well with the good data available from one ammonia spill and two hydrofluoric acid spills and, in particular, the results obtained by using the phase-change submodel represent considerable improvements over those from all-vapor simulations. While the present phase-change submodel qualitatively handles the aerosol effects, including gravity flow and heat transfer between the vapor and droplets, it tends to over-estimate the rate of droplet evaporation. 16 refs., 12 figs., 7 tabs. (ERA citation 13:012487)