• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.233-239
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• 2005

In the present study, numerical simulation has been performed to investigate the characteristics of the mist flow through the fire suppression nozzles. The commercial CFD software, FLUENT with the proper modeling was applied in both the internal and external flow region of the spray nozzles. Applications were done to the full cone nozzle for the operation range of the low pressure and high flow-rate. Numerical validation was proved by the comparison of the experimental data. Parametric study of the key design factors was tried to improve the performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.5-8
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• 2006

High strength concrete has been increasingly used in high rue building and it is very obvious re consider fire resistance performance of that. Unlike the normal strength concrete, high strength concrete in sudden elevating temperature at fire is susceptible to spalling with severe explosion and surface split, due to high density of concrete. In order to endure the spalling, inner space temperature of concrete should be control less than certain point. Therefore this study investigated the influence of covering materials on high strength concrete finishing spray-on materials of fiber composite spray mortar(FCSM). Both polypropylene(PP) and polyvinyl alcohol(PVA) fiber were used in this test. Test showed that concrete, covering 18mm mortar containing PVA fiber and confining metal lath 2.3mm thickness, decreased 50% of main bar ambient temperature. compared with control concrete. In addition, concrete covering 18mm mortar without fiber caused falling of covering materials and then it was exposed in elevating temperature. As a result, spatting of the concrete occurred same as control concrete. However, concrete covering spray-on mortar containing PVA or PP fiber resisted spatting occurrence.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.04a
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• pp.157-162
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• 2003

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2003.10a
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• pp.135-141
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• 2003

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.120-127
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• 2021

Purpose: In this study, the effect of changes in the variables related to water droplets on the spray density on the floor in the analysis of the water mist fire protection system using FDS was analyzed. Method: When the spray of the water mist nozzle was analyzed in FDS, Particles Per Seconds, Particle Velocity, Size Distribution, and Spray Pattern Shape that can be set in relation to droplets were input to review the analyzed results. Result: In the analysis results, when the number of particles per second was set above a certain value, the spray density of the floor was similar. In the case of Particle Velocity, as the velocity decreases, the spray density of the central portion increases but decreases at a distance of 0.15m or more. From the analysis of the change in the size distribution function, it was found that an increase in the 𝛾 value increases the spray density of the central part, but the value at a remote location decreases. Compared to the result of applying the Gaussian distribution, the median value decreases dramatically when the uniform distribution is applied, but the value at the adjacent position increases. Conclusion: Variables related to the droplet properties of the FDS affect the spray density of the floor. Therefore, in order to increase the reliability of results before performing analyses such as fire suppression or cooling, a sufficient review of input variables is required.

• Fire Science and Engineering
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• v.33 no.5
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• pp.28-36
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• 2019

In the present study, the effects of supply gas and water mist on the heptane pool fire extinguishing performance were investigated using the full cone and hollow cone twin-fluid atomizers. Air or nitrogen of 30 lpm (Liter per minute; L/min) was used as the supply gas, and the experiments were conducted under the water flow rate conditions of 0 lpm (i.e., discharge of air or nitrogen only) and 0.085 lpm (i.e., discharge of water mist with supply gas). Experimental results confirmed that the use of water mist discharge with the supply gas and full cone spray pattern reduced the fire extinguishing time as compared to that of only supply gas discharge and hollow cone spray pattern. In addition, for the discharge of water mist using the full cone twin-fluid atomizer, water mist significantly affected fire extinguishing performance, whereas the effect of the supply gas was less pronounced. On the other hand, for the discharge of water mist using the hollow cone twin-fluid atomizer, the fire extinguishing time was remarkably reduced by the supply of nitrogen, as compared with that of air, indicating that the supply gas as well as water mist can significantly affect fire extinguishing performance.

• Journal of Power System Engineering
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• v.13 no.5
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• pp.25-33
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• 2009

In the present study, the numerical investigation has been carried out to see the effects of water mist sprays on the fire suppression mechanism. The special-purposed program named as FDS was used to simulate the interaction of fire plume and water mists. This program solves the fire-driven flows using LES turbulence model, the mixture fraction combustion model, the finite volume method of radiation transport for a non-scattering gray gas, and conjugate heat transfer between wall and gas flow. The computational domain was composed of a rectangular space dimensioned as $L{\times}W{\times}H=4.0{\times}4.0{\times}2.5\;m^3$ with a mist-injecting nozzle installed 1.0 m high from the fire pool. In this paper, two types of nozzles were chosen to compare the performance of the fire suppression. Numerical results showed that the nozzle, type A, with more orifices having smaller diameters had poorer performance than the other one, type B because the flow injected through side holes deteriorated the primary flow. The fire-extinguishing time of type A was 2.6 times bigger than that of type B.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2002.05a
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• pp.154-162
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• 2002

• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.113-122
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• 2006

The purpose of this paper is to evaluate the fire resistance of the TSC beam, a composite beam composed of a concrete beam enclosed by steel plates. Since a discrepancy was observed between the structural mechanisms of TSC and typical composite beams, the fire performances of the two beams are likewise believed to be partially dissimilar. In this experiment, small and medium-sized TSC beams were tested under given conditions in the laboratory, with/without one of the most widely used spray-on fire protections in Korea. Furthermore, based on the steel and concrete properties under elevated temperatures that were obtained from Eurocode, temperature development across the section was suggested, analyses. To determine the capacity of a modified plastic section, th e fire performance of the model was also examined.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.37-40
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• 2005

High Performance Concrete(HPC) has been widely used in high-rise building. The HPC has several benefits including high strength, high fluidity and high durability. However. spatting is susceptible to occur in HPC and HPC also tends to be deteriorated in the side of fire resistance performance at fire. This paper focuses on the analysis of the temperature history and residual compressive strength with finishing material, in order to protect HPC from sudden-high-temperature, which is one of the main reason spatting occurs. Test results show that spalling occurs in all specimens. The most serious spalling took placed in HPC covering fire enduring spray-on material, whose covering thickness is 20mm but temperature history indicates that fire enduring spray effectively protected HPC from fire for more than 2hours. In addition, residual compressive strength ratio of HPC using fire enduring paint was more than $90\%$ of original strength, thus minimizing spatting and indicating significant fire resistance performance.