scholarly journals Numerical Investigations on the Propagation of Fire in a Railway Carriage

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4999
Author(s):  
Matthew Craig ◽  
Taimoor Asim
Keyword(s):  
Fire Spread ◽  
Ignition Energy ◽  
Fire Dynamics ◽  
Fire Propagation ◽  
Average Temperature ◽  
Smoke Density ◽  
Smoke Layer ◽  
Most Significant Change ◽  
Computational Fluid Dynamics Cfd ◽  
Safety Guidelines

In this study, advanced Computational Fluid Dynamics (CFD)-based numerical simulations have been performed in order to analyse fire propagation in a standard railway compartment. A Fire Dynamics Simulator (FDS) has been employed to mimic real world scenarios associated with fire propagation within railway carriages in order to develop safety guidelines for railway passengers. Comprehensive parametric investigations on the effects of ignition location, intensity and cabin upholstery have been carried out. It has been observed that a fire occurring near the exits of the carriage results in a lower smoke layer height, due to the local carriage geometry, than an identical fire igniting at the center of the carriage. This in turn causes the smoke density along the aisleway to vary by around 30%. Reducing the ignition energy by half has been found to restrict combustion, thus reducing smoke density and carbon exhaust gases, reducing the average temperature from 170 °C to 110 °C. Changing the material lining of the seating has been found to cause the most significant change in output parameters, despite its relative insignificance in bulk mass. A polyester sample produces a peak carbon monoxide concentration of 7500 ppm, which is 27× greater compared with nylon. This difference has been found to be due to the fire spread and propagation between fuels, signifying the polyester’s unsuitability for use in railway carriages.

scholarly journals A generic fuel moisture content attenuation factor for fire spread rate empirical models

2018 ◽  
Vol 27 (2) ◽  
pp. e009 ◽  
Author(s):  
Carlos G. Rossa
Keyword(s):  
Moisture Content ◽  
Attenuation Factor ◽  
A Priori ◽  
Fire Spread ◽  
Fuel Moisture ◽  
Ignition Energy ◽  
Spread Rate ◽  
Fire Propagation ◽  
Damping Effect ◽  
Fuel Moisture Content

Aim of study: To develop a fuel moisture content (FMC) attenuation factor for empirical forest fire spread rate (ROS) models in general fire propagation conditions.Methods: The development builds on the assumption that the main FMC-damping effect is a function of fuel ignition energy needs.Main results: The generic FMC attenuation factor was successfully used to derive ROS models from laboratory tests (n = 282) of fire spread in no-wind and no-slope, slope-, and wind-aided conditions. The ability to incorporate the FMC attenuation factor in existing field-based ROS models for shrubland fires and grassland wildfires (n = 123) was also positively assessed.Research highlights: Establishing a priori the FMC-effect in field fires benefits the proper assessment of the remaining variables influence, which is normally eluded by heterogeneity in fuel bed properties and correlated fuel descriptors.

scholarly journals Sustainable Smoke Extraction System for Atrium: A Numerical Study

2021 ◽  
Vol 13 (13) ◽  
pp. 7406
Author(s):  
Martin Lyubomirov Ivanov ◽  
Wei Peng ◽  
Qi Wang ◽  
Wan Ki Chow
Keyword(s):  
Mechanical Ventilation ◽  
Natural Ventilation ◽  
Numerical Study ◽  
Ventilation System ◽  
High Heat ◽  
Fire Dynamics ◽  
Sustainable Environment ◽  
Design Fire ◽  
Smoke Layer ◽  
Computational Fluid Dynamics Cfd

Smoke extraction systems, either static with natural ventilation, or dynamic with mechanical ventilation are required to keep smoke layer at high levels in many tall atria. It is observed that a design fire with high heat release rate (HRR) is commonly used for designing natural vents, but a low HRR is used for mechanical ventilation system. This will not produce a sustainable environment. There are no internationally agreed on design guides to determine the HRR in the design fire for different extraction systems and scenarios. This issue will be studied using a Computational Fluid Dynamics (CFD)-based software, the Fire Dynamics Simulator (FDS) version 6.7.1. Simulations on natural smoke filling, static and dynamic smoke extractions were carried out in a big example atrium. CFD-FDS predictions were compared with previous full-scale burning tests. Results confirmed that static smoke extraction is a good option for big fires, and a dynamic system is best for small fires. A sustainable new hybrid design combining the advantages of static and dynamic systems is proposed, which could result in a lower smoke temperature and higher smoke layer interface height, indicating a better extraction design.

Justification of Fire Field Models by Atrium Hot Smoke Tests

2009 ◽  
Author(s):  
W. K. Chow ◽  
S. S. Li ◽  
C. L. Chow
Keyword(s):  
Field Model ◽  
Field Tests ◽  
Design Tool ◽  
Fire Dynamics ◽  
Design Fire ◽  
Air Temperatures ◽  
Fire Environment ◽  
Measurement Results ◽  
Smoke Layer ◽  
Computational Fluid Dynamics Cfd

Computer thermal fire models are used in hazard assessment for performance-based fire design. Fire field model using Computational Fluid Dynamics (CFD) is now a popular design tool. The thermal fire environment can be predicted in a ‘microscopic’ picture with air flow pattern, pressure and temperature contours. However, most of the field models are only validated by some experiments not specially designed for such purpose. Whether those models are suitable for use is queried, leading to challenges. In this paper, prediction on smoke filling in a big atrium by the CFD tool Fire Dynamics Simulator developed at the National Institute of Standards and Technology in USA was justified by field tests. Smoke layer interface height and air temperatures inside the atrium were taken as the parameters. CFD results predicted were compared with the field measurement results.

Effects of curing on grassfires: II. Effect of grass senescence on the rate of fire spread

2015 ◽  
Vol 24 (6) ◽  
pp. 838 ◽  
Author(s):  
Miguel G. Cruz ◽  
Jim S. Gould ◽  
Susan Kidnie ◽  
Rachel Bessell ◽  
David Nichols ◽  
...  
Keyword(s):  
Fire Spread ◽  
Fire Behaviour ◽  
Fire Dynamics ◽  
Fire Propagation ◽  
Damping Effect ◽  
Study Results ◽  
Live Fuels ◽  
Degree Of Curing ◽  
Fuel Moisture Content ◽  
Fuel Components

The capacity to predict fire dynamics in fuel beds comprised of live and dead fuel components is constrained by our limited understanding of the effects of live fuels on fire propagation. A field-based experimental burning program was conducted to specifically address the effect of the degree of curing, the proportion of dead fuels in the fuel bed, on fire propagation in grasslands. Experimental fires were conducted at two sites characterised by structurally distinct fuels with curing levels varying between 20% and 100%. Fire sustainability experiments showed that fire propagation can occur down to curing levels as low as 20%. Rate of fire spread varied between 41.7 and 102 m min–1 in fully cured fuels and between 2.8 and 43.5 m min–1 in partially cured grasslands. The degree of curing was found to be the best variable describing the damping effect of live fuels in a natural, senescing grassland. Live fuel moisture content by itself was not found to be related to the damping effect of live fuels on the rate of fire spread. Existing models for the effect of grass curing on fire behaviour presently used in Australia were found to under-predict the rate of forward fire spread in partially cured grasslands. A new curing relationship for southern Australian grasslands derived from the study results is proposed.

Computer Simulation and Analysis on Fire Verification and Smoke Distribution of the Entertainment Areas

2012 ◽  
Vol 531-532 ◽  
pp. 716-719
Author(s):  
Te Chi Chen ◽  
Chia Chun Yu ◽  
Cherng Shing Lin
Keyword(s):  
Computer Simulation ◽  
Safety Management ◽  
Fire Department ◽  
Fire Spread ◽  
Fire Dynamics ◽  
Fire Dynamics Simulator ◽  
Smoke Layer ◽  
Co Concentration ◽  
Fire Scene ◽  
Fire Accident

Along with the economic growth, more crowded entertainment places are growing dramatically and the safety concerns are no longer contained as usual. The huge property damage and heavy casualties of fire caused by the owner ignorance of safety management or the fall short of the fire resistance specifications. These factors caused serious casualties after fire occurred. This research utilizes Fire Dynamics Simulator (FDS) software to analyze and simulate the fire accident that occurred in a public entertainment places on Po-Li bar, KeeLung City, Taiwan. The computer simulation calculates the fire spread and smoke distribution at the fire scene, and is in reasonable agreement with the post report provided by the fire department and photos. Simulation results of the various important parameters - such as temperature, CO concentration and smoke layer height during the fire time domain are obtained. This study will provide the improvement of fire parameters and suggestions to avoid future unfortunate events.

scholarly journals Reconstruction of Grenfell Tower fire. Part 3—Numerical simulation of the Grenfell Tower disaster: Contribution to the understanding of the fire propagation and behaviour during the vertical fire spread

2019 ◽  
Vol 44 (1) ◽  
pp. 35-57 ◽  
Author(s):  
Eric Guillaume ◽  
Virginie Dréan ◽  
Bertrand Girardin ◽  
Faiz Benameur ◽  
Maxime Koohkan ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fire Spread ◽  
Fire Propagation

Fine-Scale Fire Spread in Pine Straw

Fire ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 69
Author(s):  
Daryn Sagel ◽  
Kevin Speer ◽  
Scott Pokswinski ◽  
Bryan Quaife
Keyword(s):  
Fire Spread ◽  
Small Scale ◽  
Natural Setting ◽  
Fine Scale ◽  
Prescribed Burn ◽  
Fire Dynamics ◽  
Rate Of Spread ◽  
Scale Models ◽  
Fire Front ◽  
Visible Images

Most wildland and prescribed fire spread occurs through ground fuels, and the rate of spread (RoS) in such environments is often summarized with empirical models that assume uniform environmental conditions and produce a unique RoS. On the other hand, representing the effects of local, small-scale variations of fuel and wind experienced in the field is challenging and, for landscape-scale models, impractical. Moreover, the level of uncertainty associated with characterizing RoS and flame dynamics in the presence of turbulent flow demonstrates the need for further understanding of fire dynamics at small scales in realistic settings. This work describes adapted computer vision techniques used to form fine-scale measurements of the spatially and temporally varying RoS in a natural setting. These algorithms are applied to infrared and visible images of a small-scale prescribed burn of a quasi-homogeneous pine needle bed under stationary wind conditions. A large number of distinct fire front displacements are then used statistically to analyze the fire spread. We find that the fine-scale forward RoS is characterized by an exponential distribution, suggesting a model for fire spread as a random process at this scale.

scholarly journals A Numerical Analysis of the Fire Characteristics after Sprinkler Activation in the Compartment Fire

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3099 ◽  
Author(s):  
Ho Trong Khoat ◽  
Ji Tea Kim ◽  
Tran Dang Quoc ◽  
Ji Hyun Kwark ◽  
Hong Sun Ryou
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Fire Suppression ◽  
Compartment Fire ◽  
Fire Dynamics ◽  
Fire Dynamics Simulator ◽  
Safety Design ◽  
Smoke Layer ◽  
Fire Characteristics ◽  
Sprinkler Spray

Understanding fire characteristics under sprinkler spray is valuable for performance-based safety design. However, fire characteristics during fire suppression by sprinkler spray has seldom been studied in detail. In order to present a fire suppression model by sprinkler spray and determine the fire characteristics after sprinkler activation in a compartment, a numerical analysis was conducted using a fire dynamics simulator (FDS). A simple fire suppression model by sprinkler spray was calibrated by comparing ceiling temperatures from experimental data. An extinguishing coefficient of 3.0 was shown to be suitable for the fire suppression model. The effect of sprinkler spray on the smoke layer during fire suppression was explained, revealing a smoke logging phenomenon. In addition, the smoke, which spread under the influence of the sprinkler spray, was also investigated. The temperature, velocity, and mass flow rate of the smoke layer through the doorway was significantly reduced during fire suppression compared to a free burn case.

scholarly journals VERIFICATION OF NUMERICAL MODEL OF FIRE AND SMOKE DEVELOPMENT IN RAILWAY TUNNEL

2016 ◽  
Author(s):  
Kamila Horová ◽  
František Wald ◽  
Jiří Apeltauer
Keyword(s):  
Numerical Model ◽  
Prediction Models ◽  
Numerical Models ◽  
Fire Spread ◽  
Complex Problem ◽  
Gas Temperature ◽  
Tunnel Length ◽  
Fire Dynamics ◽  
Railway Tunnel ◽  
Mesh Density

Simulation of fire spread and development of toxic gases during a fire accident in a railway tunnel allows prepare and validate models of safe evacuation of people. Highly complex problem of fire dynamics in a tunnel can be solved by the aid of numerical models based on CFD method. In order to check the quality of prediction models the procedure of verification is used. A relatively simple model of a single track railway tunnel is solved in two independent codes - FDS and Smart Fire. Accuracy of the model prediction is verified by the aid of gas temperature resolution along the tunnel length. To estimate an error based on different mesh resolutions of numerical model, calculation of the same model is carried out using different mesh density.

Deterministic–stochastic approach to compartment fire modelling

2008 ◽  
Vol 465 (2104) ◽  
pp. 1029-1041 ◽  
Author(s):  
V Bertola ◽  
E Cafaro
Keyword(s):  
Deterministic Model ◽  
Random Noise ◽  
Stochastic Approach ◽  
Fire Dynamics ◽  
Arbitrary Degree ◽  
Compartment Fires ◽  
External Perturbations ◽  
Fire Modelling ◽  
Smoke Layer ◽  
Suitable Potential

A generalized Semenov model is proposed to describe the dynamics of compartment fires. It is shown that the transitions to flashover or to extinction can be described in the context of the catastrophe theory (or the theory of dynamical systems) by introducing a suitable potential function of the smoke layer temperature. The effect on the fire dynamics of random perturbations is then studied by introducing a random noise term accounting for internal and external perturbations with an arbitrary degree of correlation. While purely Gaussian perturbations (white noise) do not change the behaviour of the fire with respect to the deterministic model, perturbations depending on the model variable (‘coloured’ noise) may drive the system to different states. This suggests that the compartment fires can be controlled or driven to extinction by introducing appropriate external perturbations.

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