• Journal of the Korean Society of Safety
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• v.21 no.6 s.78
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• pp.46-54
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• 2006

Fire extinguishing experiment was conducted with water mist nozzle in case of the pool fire, cascade fire and spray fire on flammable liquid of class B whether water mist system can be effective system for power transformer fire scenario. In the event of a pool fire, flow rate and time to extinguish was inclined to be increased according to the obstruction rate of ignition space. Furthermore, the performance of fire extinguishing depended upon the spraying angle of the nozzles. In case of cascade fire, the effect of extinguishment was began to show from a combustion pan filled with fuel and fuel flowing plate later on.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.218-221
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• 2008

The real scale fire suppression test inside a road tunnel were carried out for water spray systems. The dimension of the tunnel is 7.5m in height and 11.6m in width. 3 different water spray nozzle systems with low operating pressure less than 3.5 bar were used in the experiment. Two types of fires were tested. One is a $1.4m^2$ heptane pool fire and the other is a 2000CC passenger car fire. From the experiment, the spray densities of tested systems were about $6.0\;l/min/m^2$ which is currunt domestic guideline. Although all the systems cannot extinguish the tested fires, it was found that they can reduce the tunnel temperature and have a capability to control and suppress the tested fire.

• Journal of ILASS-Korea
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• v.15 no.3
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• pp.124-130
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• 2010

Numerical simulation has been performed to investigate the mist flow characteristics through the fire suppression nozzles for the design purposes. The commercial softwares, FLUENT and the fire dynamic simulator, FDS with the proper modelings were chosen as the numerical tools. In order to find optimal conditions in sense of the main performances of nozzles, the spray characteristics were analyzed both inside and outside of the nozzles. Geometric factors of the injecting orifices, i.e., diameter and chamfered angle were chosen as the simulation parameters for design application. From the present numerical results, 1.0c nozzles, whose orifice-diameter was 1 mm, having the chamfered angles were shown as the best performance of the fire suppression.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1591-1599
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• 2004

A series of experiments were conducted to study the effectiveness of the extinction of a liquid pool fire with two different water atomizing nozzles. Fire source is a small-scale circular stainless steel pan of 120mm in diameter with the fuels of hexane and ethanol. K-type thermocouples were used to measure the flame and fuel temperature along the pool centerline and under fuel surface. A digital camera was used to visualize the process of the fire suppression. The experimental results show that water mist droplet size is l15∼180${\mu}{\textrm}{m}$ with nozzle A and 130∼190${\mu}{\textrm}{m}$ with nozzle B. The extinguishing time of pool fire was reduced with the increase of pressure. When water droplets are small, they do not reach the flame base since they may be deflected or evaporated by the fire plume. However, influence of flow rate is more important than droplet size on fire extinction. Among the fire extinction mechanisms, drop of flame temperature is superior to suffocation of $O_2$ concentration.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1703-1708
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$ Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $120^{\circ}$, and $180^{\circ}$). The grobal mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhaced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.28-33
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• 2003

The present study investigates the effect of injection angle of water mist on fire suppression characteristics by numerical simulation. In order to validate the temperature field by numerical simulation, the predicted results are compared with experimental data. It shows that the temperature difference between measurements and predictions are within $10^{\circ}C$. Numerical simulations of fire suppression are performed for 4 different injection angle($60^{\circ}$, $90^{\circ}$, $^120{\circ}$, and $180^{\circ}$). The global mean temperature over the fire compartment decrease with increasing of spray angle. The result shows that the heat transfer between droplets and gas phase are enhanced with the increasing of spray angle. Near the fire source, temperature field by the wide spray angle is slightly higher than that of narrow injection angle because of direct cooling of fire source.

• Fire Science and Engineering
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• v.33 no.6
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• pp.1-8
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• 2019

In this study, the effects of the characteristics of droplets of water spray on suppression of fire were analyzed numerically using fire dynamics simulator (FDS) 6.5.2. Additionally, the fire suppression characteristics by the water spray nozzle, including the extinguishing coefficient (EC), droplet size distribution function (SDF), median volumetric diameter (MVD), and droplets per second (DPS), were evaluated in terms of the decreasing normalized heat release rate (HRR) curve and cooling time. It was observed that with increase in the EC, the normalized HRR curve decreased rapidly, and the changing MVD affected the suppression of fire. In case of mono-disperse, the normalized HRR curve decreased slowly with the increase in DPS. On the contrary, in case of multi-disperse, the normalized HRR curve decreased rapidly even with a small increase in DPS.

• Fire Science and Engineering
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• v.26 no.4
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• pp.10-17
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• 2012

This study classifies the fire suppression measures implemented by wooden temples into four types according to availability of the pump trucks (water tanks) at the fire sites. And this study outlines the strategies and methods based on each type of fire suppression measure. The results show that the fire suppression strategy applied in general buildings is also employed in temples where pump trucks (water tanks) and fire-fighting water are available. For temples where trucks and water are not available, the helicopter, water bag, fire suppression strategy focused on water supply link, automatic transmission system of a fire engine's level by using radio communication network, and water bladder are used. In addition, general four-wheel-drive vehicles equipped with fire fighting tools such as motor pump, hose, nozzle, and water bladder should be deployed in fire stations around the temples. A fire suppression strategy using A-type ladders is also required.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.56-61
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• 2006

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 for analyzing both the internal and external flow of the spray nozzles. Computations were made for the full cone nozzle in the operation range of the low pressure and high flow-rate. To validate the present computational procedure, numerical results are compared with measurements in terms of K-factor, SMD, axial spray velocity and spray angles. Numerical results suggested that the present numerical model can be used as an adequate tool for a design purpose of mist-spray nozzles.

• Fire Science and Engineering
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• v.22 no.3
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• pp.216-220
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• 2008

Water mist fire suppression system utilizes the fire suppression features such as cooling of fire source, dilution of ambient oxygen, and shielding of radiation heat with the evaporation of microscopic water droplets. The momentum of water mist is relatively lower than that of larger water droplet and the infiltration of water mist to the fire source is not effective. Contribution of evaporated water vapor is liable to decline to limited portion of fire source due to its light weight and sparse density. On the other hand, the cycling water mist pattern is expected to improve the penetration force of water mist as well as the air expelling capability with the stratified spray characteristics. At this paper, we present the analyzed fire suppression capability of intermittent water spray pattern by use of FDS which is computational fire dynamics fire model. We expect this analysis can support the basic concept to the development of the prototype of water mist nozzle.