• 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 information and communication convergence engineering
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• v.2 no.3
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• pp.172-176
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• 2004

In special effects industry there is a high demand to convincingly mimic the appearance and behavior of natural phenomena such as smoke, waterfall, rain, and fire. Particle systems are methods adequate for modeling fuzzy objects of natural phenomena. This paper presents particle system graphics library for generating special effects in video games and virtual reality applications. The library is a set of functions that allow c++ programs to simulate the dynamics of particles for special effects in interactive and non-interactive graphics applications, not for scientific simulation.

• Journal of computational fluids engineering
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• v.21 no.4
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• pp.1-10
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• 2016

The analysis of characteristics of turbulent flow and thermal boundary layer for natural convection caused by fire along vertical wall is performed. The 4m-high vertical copper plate is heated and kept at a uniform surface temperature of $60^{\circ}C$ and the surrounding fluid (air) is kept at $16.5^{\circ}C$. The flow and temperature is solved by large eddy simulation(LES) of FDS code(Ver.6), in which the viscous-sublayer flow is calculated by Werner-Wengle wall function. The whole analyzed domain is assumed as turbulent region to apply wall function even through the laminar flow is transient to the turbulent flow between $10^9$<$Gr_z$<$10^{10}$ in experiments. The various grids from $7{\times}7{\times}128$ to $18{\times}18{\times}128$ are applied to investigate the sensitivity of wall function to $x^+$ value in LES simulation. The mean velocity and temperature profiles in the turbulent boundary layer are compared with experimental data by Tsuji & Nagano and the results from other LES simulation in which the viscous-sublayer flow is directly solved with many grids. The relationship between heat transfer rate($Nu_z$) and $Gr_zPr$ is investigated and calculated heat transfer rates are compared with theoretical equation and experimental data.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.3
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• pp.266-272
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• 2017

In this study, it was simulated and analyzed the evacuation safety to identify the cadets' evacuation time by using maritimeEXODUS which is applied IMO MSC.1/Circ.1238 theory as well as the trim and heel which are the major factor of reducing the ship evacuation speed. In addition, this study carried out a simulation through the special program for fire analysis - FDS (Fire Dynamics Simulator) in order to find the effective evacuation time, i.e. life survival time. Particularly, this study did comparative analysis of the influence on the survival of cadets based on the collected simulation data by fire size and sort. As a result of the analysis, It was analyzed the Evacuation Allowable Limit Temperature $60^{\circ}C$ and resulted that there is no influence in evacuation by temperature. As a result of the analysis on visibility evacuation limit 5 m, it was found that the only one evacuation rallying point could not meet the evacuation safety. However, it derived the perfect evacuation safety under the condition of two rallying points available on wood fire. In case of Kerosene, it was satisfied the evacuation safety if the heeling was under $10^{\circ}$. Moreover, it could not meet the evacuation safety by evacuating through upper deck although there were two evacuation rallying points. When it was set by the lifeboat descending maximum angle-$20^{\circ}heel$ and $10^{\circ}trim$ which was described in SOLAS regulation, it was simulated that the wood fire having two evacuation rallying points in the center of the ship satisfied the evacuation safety.

• Journal of Hydrogen and New Energy
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• v.30 no.6
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• pp.499-504
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• 2019

Due to the rapid spread and low minimum ignition energy of hydrogen, rupture is highly likely to cause fire, explosion and major accidents. The self-ignition of high-pressure hydrogen is highly likely to ignite immediately when it leaks from an open space, resulting in jet fire. Results of the diffusion and leakage simulation show that jet effect occurs from the leakage source to a certain distance. And at the end of location, the vapor cloud explosion can be occurred due to the formation of hydrogen vapor clouds by built-up. In the result, it is important that depending on the time of ignition, a jet fire or a vapor cloud explosion may occur. Therefore, it is necessary to take into account jet effect by location of leakage source and establish a damage minimizing plan for the possible jet fire or vapor cloud explosion. And it is required to any kind of measurements such as an interlock system to prevent hydrogen leakage or minimize the amount of leakage when detecting leakage of gas.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.40-45
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• 2003

To evaluate the smoke control systems, the large eddy simulation turbulence model based Fire Dynamics Simulate was applied to a 2m $\times$ 2m $\times$ 2.4m room with an opening. The smoke removal rate was investigated for three different smoke control systems: ventilation, extraction and pressurization. When the opening was closed, the smoke removal rates of the smoke control systems were almost the same as expected. The pressurization system showed a lower smoke removal rate compared with the other two smoke control systems for the room with the opening, and hence the pressurization system might not be efficient for a place with large openings. It was shown that the lower extraction flowrate is, the longer time the ventilation system requires to remove smoke. From these results, the ventilation system is recommended for subway stations where several large openings exist.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.34-38
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• 2003

The large eddy simulation based Fire Dynamics Simulator was utilized to investigate the effects of the size of an opening on smoke removal performance for the three smoke control systems-ventilation purge, and extraction. Three different opening sizes, $r_A$=1, 2, and 3 were investigated while the flow rate remained 0.75 $m^3/s$ at the inlet or outlet depending on the systems. Increase of the opening size did not give a significant difference in the smoke removal rate for the three smoke control systems, though the increasing opening size slightly improved smoke removal. The extraction system was shown the best smoke control system, and the purge system yielded low performance compared to the other two systems for all the different opening sizes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.560-564
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• 2007

In order to reduce the level of recoil force, new recoil technology must be employed. The present study discusses a soft-recoil mechanism that can reduce dramatically the recoil force. The dynamics of the soft-recoil system with hydraulic dampers are described and simulated. The results of the simulation show that FOOB system can reduce the recoil force and the recoil stroke compared to conventional systems. However, the FOOB system is not able to perform well when the fault modes happen. Hence, this study uses the MR damper to achieving FOOB under fault modes.

• Journal of Advanced Marine Engineering and Technology
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• v.36 no.3
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• pp.368-377
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• 2012

Most tunnel simulations have been focused on the thermal field and the critical velocity for suppression of hot back-layering flow in case of fire and on the characteristics of a tunnel fire in terms of the flame propagation and the toxic gas generation. In this paper, a comparative study of the flow characteristics of polluted air with no heat source in a tunnel model opened and closed at both end sides is implemented into a recognized CFD simulation code. The model is used to investigate the flow characteristics depending on the three different Reynolds numbers of 640, 1270 and 2120, which have been chosen by the flow velocities of 0.3, 0.6 and 1.0 m/s through the inlet. The results of this study have shown that the CFD predictive and experimental approaches are available in qualitatively studying the correlation of flow behaviors for a better tunnel design.

• Fire Science and Engineering
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• v.31 no.4
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• pp.26-34
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• 2017

The purpose of this study is to identify and improve the performance of the adjacent room ventilation system in living room ventilation facilities, and compare and analyze the smoke control regulations of the NFPA code and the national fire safety standard (NFSC). The analysis method was fire dynamics simulation (FDS) and was used to analyze the, variations of the air supply amount, width of the boundary, change in indoor combustion and wind velocity of the incoming air. It was found to be advantageous to secure the clean layer when the amount of air supplied is less than the amount of discharged air in the fire room. However, in the supply room, it is more effective to secure the clean layer when the amount of supplied air is larger than the amount of discharged air, as a longer boundary width gives rise to better performance. In addition, it is necessary to consider the amount of air supplied and discharged as a function of the kind of flammable material. Moreover, decreasing the air inlet wind speed and amount of incoming air is advantageous for securing the clean layer of the fire room.