• Journal of the Korean Institute of Gas
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• v.14 no.6
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• pp.31-37
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• 2010

In this study, to propose the analysis method of heat and smoke behavior of fire using the CFD-based fire simulator FDS, comparison of the simulation results against the experimental results and the sensitivity of the results to the grid sizes have been investigated. For the wood fire, thermal images captured from the experiments were compared against the FDS simulations, and the maximum temperatures agreed in~4.3 % error, showing the applicability of FDS in the interpretation of the fire phenomena. In the aspect of the sensitivity to the grid size for the subway fire, FDS results of smoke temperature, CO concentration and visibility converged and showed no distinct changes for the grid size < $28(L){\times}28(W){\times}14(H)$, guaranteeing that the FDS fire model set in this research could interpret the fire phenomena successfully.

• Journal of the Korean Society of Visualization
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• v.4 no.1
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• pp.8-13
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• 2006

Fire simulation has been developed for decades to analyze fire cases and provide a tool to study fundamental fire dynamics and combustion. There are three way of fire simulation which are a full scale simulation, an experimental simulation and a computational simulation. In case of a full scale simulation, because a higher cost, a higher risk, more efforts are needed, a demand for it has been decreased. But recently a demand for an experimental simulation and a computational simulation has been increased. A computational simulation has several advantages; lower cost, short period, many case studies, more visual results, a quantitative result and etc. FDS(Fire Dynamics Simulator) which has been developed in BFRL(Building and Fire Research Laboratory), NIST(National Institute of Standards and Technology) is a popular world wide code for fire simulation. Lack of accurate predictions by the model could lead to erroneous conclusions with regard to fire safety. All results should be evaluated by the informed judgment of the qualified user.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.11
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• pp.1617-1624
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• 2013

This paper analyzes the relation between fire shutters and fire spread by conducting fire simulation on inner space with fire shutters. Using Fire Dynamics Simulator (FDS), a commercial fire simulation software, the simulation is done on an ideal inner robby, where fire size and the open/close of fire shutters are varied. Our simulation environment can derive significant fire parameters such as temperature variation of fire room walls and entrances of refuge stairs, variation of carbon dioxide, and soot spread. According to the simulation results, temperature and carbon dioxide distribution in refuge stairs have little dependence on vent open or close, but the part close of fire shutters blocks soot inflow to refuge stairs.

• Fire Science and Engineering
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• v.33 no.4
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• pp.50-58
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• 2019

The prediction performance of B-RISK was evaluated for the fire behaviors of combustibles in a compartment using Fire Dynamics Simulator (FDS). First of all, to predict the heat release rate (HRR) for two combustible sets, the HRR for one combustible set and the design fire curve were used as input values for B-RISK. Comparing results of B-RISK calculations with experimental data for two combustible sets, it was found that B-RISK results predicted insufficiently for fire growth rate of experimental data but there was good agreement for maximum HRR and total HRR with the experimental data. And the B-RISK results were used for input values of FDS to evaluate the fire behaviors of B-RISK results. Comparing results of FDS calculations with experimental data, the simulation results showed that the temperature and concentrations of O₂, CO₂ in the fire growth phase were different from the experimental data. However, when using the B-RISK result for percentile 70%, the simulation results sufficiently predicted the overall fire behaviors.

• Steel and Composite Structures
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• v.10 no.2
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• pp.129-149
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• 2010

The objective of this study is to formulate a general 3D material-structural analysis framework for the thermomechanical behavior of steel-concrete structures in a fire environment. The proposed analysis framework consists of three sequential modeling parts: fire dynamics simulation, heat transfer analysis, and a thermomechanical stress analysis of the structure. The first modeling part consists of applying the NIST (National Institute of Standards and Technology) Fire Dynamics Simulator (FDS) where coupled CFD (Computational Fluid Dynamics) with thermodynamics are combined to realistically model the fire progression within the steel-concrete structure. The goal is to generate the spatial-temporal (ST) solution variables (temperature, heat flux) on the surfaces of the structure. The FDS-ST solutions are generated in a discrete form. Continuous FDS-ST approximations are then developed to represent the temperature or heat-flux at any given time or point within the structure. An extensive numerical study is carried out to examine the best ST approximation functions that strike a balance between accuracy and simplicity. The second modeling part consists of a finite-element (FE) transient heat analysis of the structure using the continuous FDS-ST surface variables as prescribed thermal boundary conditions. The third modeling part is a thermomechanical FE structural analysis using both nonlinear material and geometry. The temperature history from the second modeling part is used at all nodal points. The ABAQUS (2003) FE code is used with external user subroutines for the second and third simulation parts in order to describe the specific heat temperature nonlinear dependency that drastically affects the transient thermal solution especially for concrete materials. User subroutines are also developed to apply the continuous FDS-ST surface nodal boundary conditions in the transient heat FE analysis. The proposed modeling framework is applied to predict the temperature and deflection of the well-documented third Cardington fire test.

• Journal of the Korean Institute of Gas
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• v.19 no.1
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• pp.38-44
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• 2015

FDS (Fire Dynamics Simulator) is the most widely used computational fluid dynamics software in the fire safety engineering community, and it is applicable to various evaluations of fire growth and its effects. This study made use of a range of outputs from FDS simulation to predict FED (Fractional Effective Concentration) and FEC (Fractional Effective Concentration) levels which are often adopted to evaluate toxicity of fire smoke. As it is not possible to calculate these values directly from outputs of FDS, it was necessary to produce them by means of additional calculation procedures incorporating results of evacuation simulation. In this study, the latest version of FDS, which was recently updated in November 2013, was utilized for the purpose of quantitative comparison with the old version of FDS. As a result, it was found that they make about 10 percent difference on average in predicting FED and FEC levels for the cable fire case study.

• Fire Science and Engineering
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• v.23 no.5
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• pp.133-137
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• 2009

The Fire Dynamics Simulator (FDS), a computational fluid dynamics model for fire simulation, was applied to propylene vertical wall fires, to confirm its accuracy in simulation of vertical wall fires. The temperature profiles at the center of the burner obtained for mass loss rates per unit area in the range of $7.0{\sim}29.29g/m^2-s$ were compared with those of experiment. Comparisons of the heat flux distributions along the vertical centerline on the wall surface were made with the measurements. It was shown that the computed temperature profiles were in good agreement with the experiment. It was also noted that the peak temperature near the wall was underpredicted, the heat flux was too high compared with the measurements, and hence improvements are required for FDS in simulation of the vertical wall fires.

• Fire Science and Engineering
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• v.33 no.2
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• pp.47-55
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• 2019

The prediction performance of design fire curves was evaluated using a Fire dynamics simulator (FDS) for a solid fuel fire in a building space by comparing the results with experimental data. EDC 2-step mixing controlled combustion model was used in the FDS simulations and the previously suggested 2-stage design fire (TDF), Quadratic and Exponential design fire curves were used as the FDS inputs. The simulation results showed that smoke propagation in the building space was significantly affected by the design fire curves. The predictions of simulations using design fire curves for the experimental temperatures in the building space were reasonable, but the TDF was found to be the most acceptable for predicting temperature. The predictions with each design fire curve of species concentrations showed insufficient agreement with the experiments. This suggests that the combustion model used in this study was not optimized for the simulation of a solid fuel fire, and additional studies will be needed to examine the combustion model on the FDS prediction of solid fires.

• Fire Science and Engineering
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• v.33 no.5
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• pp.7-12
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• 2019

To investigate the influence of the char layer formed during the combustion process on the pyrolysis of wood combustibles, ISO 5660-1 cone calorimetry experiments and Fire dynamics simulator (FDS) simulations were performed, and the results from these two methods were compared. The wood combustible selected as the fuel for this study, Douglas fir, has been widely used for the production of building materials, furniture, etc. The heat release rate (HRR) measured from the cone calorimetry experiment was in good agreement with the result predicted by the FDS simulation. However, the FDS simulation failed to predict the heat released by the smoldering combustion process, due to the absence of the char surface reaction in the model. The FDS simulation results clearly indicate that the char layer formed on the surface of combustibles produces a thermal barrier which prevents heat transfer to the interior, thickening the thermal depth and thus reducing the pyrolysis rate of combustibles.

• Fire Science and Engineering
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• v.32 no.3
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• pp.42-50
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• 2018

The effect of sub-grid turbulence and combustion models on the mean flame height in a heptane pool fire according to the Fire Dynamics Simulator (FDS) version (5 and 6) based on Large Eddy Simulation (LES) was examined. The heat release rate for the fire simulation was provided through experiments performed under identical conditions and the predictive performance of the mean flame height according to FDS version was evaluated by a comparison with the existing correlation. As a result, the Smagorinsky and Deardorff turbulence models applied to FDS 5 and 6, respectively, had no significant effects on the mean flow field, flame shape and flame height. On the other hand, the difference in pool fire characteristics including the mean flame height was due mainly to the difference in the mixture fraction and Eddy Dissipation Concept (EDC) combustion models applied to FDS 5 and 6, respectively. Finally, compared to FDS 6, FDS 5 provided the predictive result of a significantly longer flame height and more consistent mean flame height than the existing correlation.