Abstract:
In the present work, Computational Fluid Dynamics (CFD)
explosion simulations are performed in a large scale tunnel.
The length of the tunnel is approximately equal to one
kilometer. Three different cases of explosion are studied: Vapor
Cloud Explosion (VCE), Cold BLEVE (Boiling Liquid
Expanding Vapor Explosion) and Hot BLEVE. The main
purpose of this study is the calculation of the generated
overpressures inside the tunnel and the comparison of the
pressure dynamics among these type of explosions. Realistic
scenarios are chosen for each explosion based on the traffic of
the tunnel. In the Vapor Cloud Explosion case, the release and
dispersion of 23100 kg propane into the atmosphere are
simulated in order to calculate the concentration distribution in
the tunnel. Both external wind and piston effect due to vehicles’
movement was taken under account in the dispersion process.
Then the mixture is ignited and the deflagration process is
simulated in order to calculate the generated overpressures. In
the Cold BLEVE case the total loss of confinement of a 29 m3
high pressure (57 bar) carbon dioxide storage tank is simulated,
whereas in the Hot BLEVE case the total loss of confinement
of a 46 m3 propane storage tank (at 18 bar) is considered. The
total loss of confinement of the tanks lead to a violent
expansion due to evaporation. As a result high overpressures
are generated. The transient three dimensional Navier-Stokes
equations of the multispecies mixture along with the continuity
equation, the conservation equation of species and the energy
equation are solved. Turbulence is modelled with the standard
k-ε model. In the Vapor Cloud Explosion case a Multi-
Phenomena turbulent burning velocity combustion model is
used. In the Hot BLEVE case, fire is modeled using the Eddy
Dissipation Concept (EDC) model. The simulation results
reveal that the modeling approach that is used is capable of
reproducing physical realistic results. Differences in pressure
dynamics among the scenarios are revealed due to the different
physics of the explosions.
Description:
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.
