Thermo-Fluid Dynamics Analysis of Fire Smoke Dispersion and Control Strategy in Buildings

Ricardo S. Gomez,Victor H. V. Viana,Antonio C. Q. Santos,Túlio R. N. Porto,Antonio G. B. Lima,Hortência L. F. Magalhães,Kelly C. Gomes

doi:10.3390/en13226000

Abstract

Smoke is the main threat of death in fires. For this reason, it becomes extremely important to understand the dispersion of this pollutant and to verify the influence of different control systems on its spread through buildings, in order to avoid or minimize its effects on living beings. Thus, this work aims to perform thermo-fluid dynamic study of smoke dispersion in a closed environment. All numerical analysis was performed using the Fire Dynamics Simulator (FDS) software. Different simulations were carried out to evaluate the influence of the exhaust system (natural or mechanical), the heat release rate (HRR), ventilation and the smoke curtain in the pollutant dispersion. Results of the smoke layer interface height, temperature profile, average exhaust volumetric flow rate, pressure and velocity distribution are presented and discussed. The results indicate that an increase in the natural exhaust area increases the smoke layer interface height, only for the well-ventilated compartment (open windows); an increase in the HRR accelerates the downward vertical displacement of the smoke layer and that the 3 m smoke curtain is efficient in exhausting smoke, only in the case of poorly ventilated compartments (i.e., with closed windows).

Highlights

Fire is an irreversible process that involves the production of flame, heat, smoke and toxic gases, which can cause material losses, physical trauma, severe burns, respiratory and cardiovascular diseases, and death [1,2]
Despite presenting advantages in delaying the downward vertical displacement of the smoke layer and in reducing the internal temperature, the mechanical exhaust system reported in case 12, promotes very high speeds (3.00 m/s) in the occupation area of people inside the compartment, more than double the values obtained for cases 6 and 11
This work aimed to perform a numerical analysis, using the Fire Dynamics Simulator (FDS) software, to evaluate the flow rates adopted for mechanical exhaust systems are greater than the maximum value reached by thermo-fluid dynamic behavior of the smoke generated by a fire in an enclosed space

Summary

Introduction

Fire is an irreversible process that involves the production of flame, heat, smoke and toxic gases, which can cause material losses, physical trauma, severe burns, respiratory and cardiovascular diseases, and death [1,2]. According to Anseeuw et al [14], 60% to 80% of deaths at the fire scene are attributed to smoke inhalation. This is because, during a fire, the burning of solid fuels causes a reduction in the oxygen concentration in the environment and an incomplete combustion of gases, generating highly toxic products such as CO and HCN, contributing to the occurrence of death by asphyxiation at the fire scene [10]. In addition to the problem of inhalation, smoke can cause fear, panic, tearing and irritation of the eyes, and reduced visibility, factors in turn make it difficult to safely exit the building

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