• Journal of Korean Neurosurgical Society
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• v.63 no.2
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• pp.137-152
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• 2020

In spite of the developing endovascular era, large (15-25 mm) and giant (>25 mm) wide-neck cerebral aneurysms remained technically challenging. Intracranial flow-diverting stents (FDS) were developed to address these challenges by targeting aneurysm hemodynamics to promote aneurysm occlusion. In 2011, the first FDS approved for use in the United States market. Shortly thereafter, the Pipeline of Uncoilable or Failed Aneurysms (PUFS) study was published demonstrating high efficacy and a similar complication profile to other intracranial stents. The initial FDA instructions for use (IFU) limited its use to patients 22 years old or older with wide-necked large or giant aneurysms of the internal carotid artery (ICA) from the petrous segment to superior hypophyseal artery/ophthalmic segment. Expanded IFU was tested in the Prospective Study on Embolization of Intracranial Aneurysms with PipelineTM Embolization Device (PREMIER) trial. With further post-approval clinical data, the United States FDA expanded the IFU to include patients with small or medium, wide-necked saccular or fusiform aneurysms from the petrous ICA to the ICA terminus. However, IFU is more restrictive in South Korea than in United States. Several systematic reviews and meta-analyses have sought to evaluate the overall efficacy of FDS for the treatment of cerebral aneurysms and consistently identify FDS as an effective technique for the treatment of aneurysms broadly with complication rates similar to other traditional techniques. A growing body of literature has demonstrated high efficacy of FDS for small aneurysms; distal artery aneurysms; non-saccular aneurysms posterior circulation aneurysms and complication rates similar to traditional techniques. In the short interval since the Pipeline Embolization Device was first introduced, FDS has been firmly entrenched as a powerful tool in the endovascular armamentarium. As new FDS are developed, established FDS are refined, and delivery systems are improved the uses for FDS will only expand further. Researchers continue to work to optimize the mechanical characteristics of the FDS themselves, aiming to optimize deploy ability and efficacy. With expanded use for small to medium aneurysms and posterior circulation aneurysms, FDS technology is firmly entrenched as a powerful tool to treat challenging aneurysms, both primarily and as an adjunct to coil embolization. With the aforementioned advances, the ease of FDS deployment will improve and complication rates will be further minimized. This will only further establish FDS deployment as a key strategy in the treatment of cerebral aneurysms.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.93-99
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• 2009

본 연구는 ISO-9705 표준화재실의 40% 축소모형실험 결과와 FDS 화재해석 결과의 비교분석을 통하여 FDS 화재해석 모델에 적용된 CO 와 soot의 생성율(yield rate)에 기초한 접근방식의 타당성을 검토한다. 일반적으로 생성율은 연료적인 특성인 동시에 공간의 환기조건이나 열적조건등에 영향을 받게 된다. 그러나 FDS 해석에 적용되는 연료의 생성율은 환기량이 충분한 상태(well ventilated condition)에서 측정되어진 물성으로써 공간내부의 CO와 soot 농도는 연료의 종류와 화원의 크기에 의해서만 결정된다. 따라서 환기조건과 연료특성에 따른 화재공간 내부에서의 CO와 soot 농도를 측정하여 이 결과를 FDS 시뮬레이션 결과와 직접 비교함으로써 환기조건 및 연료종류에 따른 CO 와 soot의 생성율 개념의 타당성을 고찰해보고자 한다.

• Fire Science and Engineering
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• v.25 no.5
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• pp.93-99
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• 2011

In the present study, a numerical simulation was conducted to estimate the prediction performance of FDS on the carbon monoxide production in the under-ventilated compartment fires. Methane and heptane fires located in the a 2/5 scale compartment based on the ISO-9705 standard room was simulated using FDS Ver. 5.5. Through the comparison between the computed results and the earlier published experimental data, the performance of FDS was estimated on the predictions of the combustion gases concentration in the hot upper layer of the compartment and the effects of CO yield rate on the estimation of CO production at local points were analyzed. From the results, it was known that FDS Ver. 5.5, in which the two-step reaction mixture fraction model implemented, was more effective on the prediction of CO concentration compared to the previous FDS version. In addition, controlling CO yield rate made the predicted CO concentration get closer to the experimental data for the fires of the under-ventilated condition.

• 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.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.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.9-15
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• 2011

This study aims to validate predictive capabilities of FDS for the pool fire in three rooms connected to ventilation network. The three rooms in real scale fire test facility are configured to be similar to that of nuclear power plant in size, ventilation condition, construction material, etc. Basically three rooms are confined to the other area except two open doors and two ventilation duct in each room. The real scale fire test was conducted with these conditions and the predictive capabilities of FDS will be validated by comparing FDS simulation results with experimental data from the temperature, heat flux, and concentration point of view. This study concludes that temperature from FDS is about 25 % lower deviation from the experiment, and heat flux from FDS is about 5% deviation.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.288-289
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• 2022

본 연구에서는 FDS(Fire dynamic simulation)를 이용하여 대형물류창고 화재에 대한 국내 스프링클러 설비 설치기준(NFSC)과 미국 방화협회규정(NFPA)의 스프링클러 설비 설치기준을 각각 시뮬레이션하여 발열량 및 반응물질, 초기 화재진화 정도 등의 데이터를 비교 분석하여 대형물류창고에 대한 스프링클러설비 설치기준 개선방안을 제시하고자 한다.

• 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.27 no.2
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• pp.80-88
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• 2013

The validation of Fire Dynamics Simulator (FDS) was conducted for the under-ventilated fire in well-confined multi-compartments representative of nuclear power plant. Numerical results were compared with experimental data obtained by the OECD/NEA PRISME project. The effects of the numerical boundary conditions (B.C.) in ventilated system and the flame suppression model applied within FDS on the thermal and chemical environments inside the compartment were discussed in details. It was found that numerical B.C. on the vent flow resulting from over-pressure at ignition and under-pressure at extinction should be considered carefully in order to predict accurately the species concentrations rather than temperatures and heat fluxes inside the multi-compartment. The default information of suppression model applied within FDS resulted in artificial phenomena such as flame extinction and re-ignition, and thus the FDS results on the under-ventilated fire showed good agreement with the experimental results as the modified suppression criteria of the fuel used was adopted.

• Fire Science and Engineering
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• v.26 no.5
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• pp.105-110
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• 2012

The present study investigates the effects of sprinkler spray on fire driven flow characteristics in a compartment based on numerical approach. The FDS (Fire Dynamics Simulator), a widely used fire field model, was used to simulate the fire induced flow and sprinkler spray and a series of grid independence tests have been performed to obtain the optimal grid size. In order to validate the result predicted by FDS model, the calculated results were compared with experimental results of Magnone et al.. The FDS model matches quite well to experiments in temperature profile and mass flux through doorway, however, the discrepancy between the FDS model and experiments increases with increasing water discharge rate. As with previous study, the FDS calculation also shows a decrease of mass flow rate of combustion products through doorway due to the sprinkler spray. This study can contribute to optimize the sprinkler system design and verify the validity of the fire field model with sprinkler spray.