Numerical simulation of pressure changes in closed chamber fires

Abstract

Pressure rising in closed chamber fires will be studied numerically in this paper with Computational Fluid Dynamics (CFD). The Fire Dynamics Simulator (FDS) developed at the National Institute of Standards and Technology (NIST) in USA is taken as the simulation tool. Experiments on closed chamber fires were reported in the literature by the Defence Research Establishment (FoA) in Sweden. Scenarios similar to those in that experimental study were taken as examples for simulation. Air flow pattern, pressure and temperature distribution are predicted. Functional analysis is used to compare predicted values with experiments. This gives some indication on how good CFD can be when applied for studying closed chamber fires. It is observed that input heat release rate to FDS is a key point. Predicted results on air velocities, temperature and pressure agree reasonably well with experimental results. Care should be taken in applying the fast reaction mixture fraction combustion model for simulating under-ventilated fires.