Comparative assessment of CFD Tools and the Eurocode Methodology in describing Externally Venting Flames

Laboratory of Heterogeneous Mixtures and Combustion Systems, Thermal Engineering Section, School of Mechanical Engineering, National Technical University of Athens 9 Heroon Polytechneiou St., Polytechneioupoli Zografou, Athens 15780, Greece

^a e-mail: elasimak@mail.ntua.gr

Abstract

The ability of currently available Computational Fluid Dynamics (CFD) tools to adequately describe Externally Venting Flames (EVF) is assessed, aiming to demonstrate compliance with performance-based fire safety regulations. The Fire Dynamics Simulator (FDS) CFD tool is used to simulate the EVF characteristics in a corridor-compartment-façade configuration exposed to natural fire conditions. Numerical results of the temporal evolution of gas velocity, gas temperatures and flame shape are obtained for both the interior and the exterior of the compartment. Predictions are compared to respective experimental data, as well as to correlations suggested by the Eurocode methodology. The effects of ventilation conditions are investigated by simulating both Forced Draught (FD) and No Forced Draught (NoFD) test cases. The obtained results suggest that currently available CFD tools are capable of achieving good qualitative agreement with experimental data and, in certain cases (e.g. FD conditions), adequate quantitative agreement, that generally outperforms the Eurocode prescriptive methodology.