• 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.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.50-55
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• 2008

The comparative analysis of fire-driven flow simulation for Dae-Gu subway station was performed using FDS and Fluent. The boundary condition was obtained from analyzed data for Dae-Gu subway fire accident which had been outbreaked in 2003 year. The smoke flow in the second and third basement has been analyzed. The CO and temperature distribution in the train units and station platform have been obtained with FDS and FLUENT and compared with each other. Total simulation time is 600s and the results are compared of each 10sec The analyzed data will be applied to the passenger evacuation simulation for Dae-Gu subway station and used to optimal design method.

• Fire Science and Engineering
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• v.23 no.5
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• pp.103-109
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• 2009

In this study, fire simulations on the under-ventilated compartment fires have been conducted using the Fire Dynamics Simulator (FDS Ver. 5.2) and its prediction performance on the thermal and combustion chemical characteristics has been discussed. The temperature and chemical species concentrations in the upper layer of methane, heptane, and toluene fires located in a 2/5 scale compartment based on the ISO-9705 standard room are predicted and compared with the previously published experimental data. The results showed that the FDS simulations reproduced well the temperature of the ceiling and the mixture fraction in the upper layer under the well-ventilation conditions. For the under-ventilated fires, which were taken place due to the insufficient oxygen entrainment, the prediction by the FDS significantly under-estimated the production of carbon monoxide and soot compared to the experimental data.

• Fire Science and Engineering
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• v.32 no.1
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• pp.7-15
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• 2018

The prediction performance of combustion models in the Fire Dynamics Simulator (FDS) were evaluated by comparing with experiment for compartment propane gas fires. The mixture fraction model in the FDS v5.5.3 and Eddy Dissipation Concept (EDC) model in the FDS v6.6.3 were adopted in the simulations. Four chemical reaction mechanisms, such as 1-step Mixing Controlled, 2-step Mixing Controlled, 3-step Mixing Controlled and 3-step Mixed (Mixing Controlled + finite chemical reactions) reactions, were implemented in the EDC model. The simulation results with each combustion model showed similar level for the temperature inside the compartment. The prediction performance of FDS with each combustion model showed significant differences for the CO concentration while no distinguished differences were identified for the $O_2$ and $CO_2$ concentrations. The EDC 3-step Mixing Controlled largely over-predicted the CO concentration obtained by experiment and the mixture fraction model under-predicted the experiment slightly. The EDC 3-step Mixed showed the best prediction performance for the CO concentration and the EDC 2-step Mixing Controlled also predicted the CO concentration reasonably. The EDC 1-step Mixing Controlled significantly under-predict the experimental CO concentration when the previously suggested CO yield was adopted. The FDS simulation with the EDC 1-step Mixing Controlled showed difficulties in predicting the $CO_2$ concentration when the CO yield was modified to predict the CO concentration reasonably.

• Fire Science and Engineering
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• v.31 no.2
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• pp.44-51
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• 2017

Accurate predictions of the activation time for smoke detectors using a fire simulation is are required to ensure the reliability of the RSET (Required Safe Egress Time) calculation in the process of PBD (Performance-Based Design). The objective of this study was to enhance the accuracy of input parameters for the numerical models of smoke detector based on the FDS. To this end, a Fire Detector Evaluator (FDE) developed in previous studies was improved. The uniformities of flow and smoke inside the FDE were improved and accurate measurements of the obscuration per meter (OPM) related to detector operation were also performed through a decrease in the forward scattering of smoke particles. The input parameters using the improved FDE showed a significant difference from the previous FDE quantitatively. In particular, a larger difference was found in a photoelectric detector compared to an ionization detector. Considering that the operating conditions of smoke detectors are affected by the detector type, combustibles, smoke particulars, and color, the database (DB) on the input parameters for various detectors and combustibles should be built to improve the reliability of PBD in future studies.

• Fire Science and Engineering
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• v.26 no.2
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• pp.40-52
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• 2012

This paper presents the uncertainty analysis results of fire modeling input parameters for motor control center in switchgear room of nuclear power plants. FDS (Fire Dynamics simulator) 5.5 was used to simulate the fire scenario and Latin Hyper Cube Monte Carlo simulations were employed to generate random samples for FDS input parameters. The uncertainty analysis results of input parameters are compared with those of the model uncertainty analysis and sensitivity analysis approaches of NUREG-1934. The study results show that the input parameter uncertainty analysis approach may lead to more conservative results than the uncertainty analysis and sensitivity analysis methods of NUREG-1934.

• Fire Science and Engineering
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• v.28 no.1
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• pp.1-11
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• 2014

This study aims to address the fire characteristics of Double-skin facade using the Fire Dynamics Simulator (FDS). To end this, Double-skin facade was classified into the four structures, that is Box, Shaft-box, Corridor, Multistory, through PyroSim program which was based on FDS, and further each structure of fire characteristics were analyzed numerically as well as comparatively in the current study. This study also examined smoke movement, smoke density, smoke detectors, and visibility in order to closely identify the each structure of fire characteristics. The results of the study discovered that the Box structure did not significantly affect smoke which was rising in the other rooms, except for the fire room whereas the Corridor structure had positive effects on Double-skin facade horizontally. In addition, the Shaft-box structure showed the fastest vertical movement by means of the shaft, on the other hand, rising smoke influenced the other rooms as well. The Multistory structure along with rising smoke had a great impact on the other divided rooms in a vertical way.

• Journal of the Korean Society of Safety
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• v.23 no.4
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• pp.30-35
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• 2008

The present study has been conducted to examine the effect of grid resolution on the predicted results for electric cable fire using pyrolysis model in FDS(Fire Dynamics Simulator, version 5). The grid independent test for different grid resolutions has been performed for a PE coating cable and the grid resolution is defined by the non-dimensional characteristic length of fire and mean grid size. The calculated maximum heat release rate and mean flame spread rate were almost constant for higher grid resolution of 20${\sim}$25 and the computing time for the grid resolution takes approximately 20hours to solve flame propagation with pyrolysis model. The geometrical simplification of a electric cable dose not greatly affect on the maximum heat release rate and flame spread rate and the rectangular approximation of cable shape gives acceptable result comparing with the round cable with stepwise grid.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.32-40
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• 2017

The current status of Performance-Based Design (PBD) implemented in 4 wide areas (Seoul, Gyeonggi, Incheon and Busan) over the past 5 years was reviewed with regard to the number of PBD implementation and target buildings. Then, detailed status related to fire scenarios, input information for fire simulation, and grid size were analyzed with the pre-review for the PBD. As a result, the domestic PBD was mainly applied to the mixed occupancy. In the fire simulations performed on the identical fire scenario and fire space, the maximum heat release rate (HRR) varied significantly depending on the PBD designer. Various combustibles were also considered for the identical fire source, and their combustion properties also showed considerable uncertainty. In addition, the applicability of accurate input information for predictive models of heat and smoke detectors was examined. Finally, the average grid size for the fire simulation using Fire Dynamics Simulator (FDS) was analyzed, and the improvement of PBD to minimize designer dependency was proposed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.663-673
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• 2011

In this study, we analysed the effect of the fire source in the warehouse under the bridge and the height of the bridge using FDS code. To compare accuracy of simulation results, we simulated the experimental result with unit combustibles which is heptane as well as the mock-up test. Using this method, we evaluated the fire safety of the bridge which contains spalling and strength damage of concrete as well as damage of reinforcements according to the fire source and the height of the bridge. Most of the bridges are vulnerable to spalling of concrete. The book combustion has the strongest fire intensity which is expected to damage the bridge less than 30m height in the three types of the fire sources. The bridge over the 30m height can ensure the fire safety in the case of the rubber combustion.