Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
A NUMERICAL STUDY ON THE INFLUENCE OF THE ATMOSPHERIC WIND IN THE FIRE DYNAMICS AND HEAT TRANSFER IN A COMPARTMENT FIRE
Submission Author:
Calisa Lemmertz , RS
Co-Authors:
Calisa Lemmertz, Felipe Roman Centeno, David Rush, Mohamed Beshir
Presenter: Calisa Lemmertz
doi://10.26678/ABCM.COBEM2021.COB2021-0982
Abstract
Although wind conditions are acknowledged to influence significantly fire dynamics and enhance the external fire spread in urban and wildland fires, still little work and research has been made to comprehend the effect of external wind conditions in fire dynamics and fire spread in urban fires. This study aims to analyze the effect of the atmospheric wind in the fire dynamics and heat transfer in a post-flashover compartment fire. A series of numerical experiments was conducted through a CFD code namely Fire Dynamic Simulator (FDS) for a full-scale ISO 9705 room for different wind speeds (0 m/s, 5 m/s, 10 m/s, 15 m/s, 20 m/s and 25m/s), wind directions (side wind and back wind) and compartment boundary characteristics (thermally-thin and thermally-thick). A mesh resolution analysis was performed to ensure the quality of the numerical results. Additionally, the numerical model was validated comparing the obtained results to under-ventilated, post-flashover compartment fire experimental data available in the literature, showing a good agreement. The study showed that both, wind speed and direction can affect significantly the wall and hot gas temperatures, and also the heat fluxes through the compartment walls. For a constant heat release rate (HRR), the average windward wall (internal and external) temperatures and the hot gas temperatures were inversely proportional to the wind speed. It was also observed that thermally-thin and thermally-thick compartments are affected differently by the atmospheric wind, the thermally-thin presenting more uniform gas temperature profiles and having their net wall heat fluxes more affected by the wind.
Keywords
fire dynamics, Heat transfer, atmospheric wind, post-flashover, under-ventilated compartment fire
