The current work presents a three-dimensional CFD code for pre-
diction of gas explosion in complex geometries. The solver is based on CFD
(Computational Fluid Dynamics) techniques and uses the Porosity Distributed
Resistance (PDR) concepts to model the geometry under study. The code, called
PFS (Porosity Flow Solver), comprises a explicit finite-volume solver based on a
structured Cartesian grid developed at the University of Campinas. The Boussi-
nesq formulation is used to model the turbulence and the flamelet concepts state
of the art is used in combustion modelling.