ABSTRACT
Releases of heavy flammable gases are responsible of many major civil and industrial incidents with very large property loss and number of casualties.
Fire Dynamics Simulator 5, FDS5, is a fire modelling CFD code developed by NIST.
This code is specifically suited to deal with multicomponent buoyancy driven natural
flow, where the low Mach number assumption holds and the pressure is slightly
different from the background atmospheric value. This study presents a comparison
between analytical and experimental results relevant to heavy flammable gas dispersion
and FDS5 predictions. Comparison with dispersion experiments show that
concentrations and cloud arrival times can be predicted by the code, although an
arbitrary choice of the turbulent Schmidt number is required to match the concentration
profiles observed in those release where the flow is purely gravity driven, as in calm
conditions on a slope.
Keywords: FDS5, Heavy gas dispersion, CFD.
