• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.537-540
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• 2008

A numerical study has been carried out on the optimization of an air cleaning system which was installed in a heating, ventilation and air conditioning system (HVAC) system of subway station for particle removal. Required particle removal efficiencies of three different air cleaning systems were calculated from ventilation rate, and indoor/outdoor concentration of PM10. Mass balance equations of PM10 were used to solve the required particle removal efficiencies. Fibrous filter was considered as an air cleaning system. Calculations were carried out about two different places which were waiting area and platform of subway station, respectively. This study proposed optimized design and operation condition of each air cleaning system.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1307-1312
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• 2007

This experiments are performed to investigate the effect of ventilation velocity on a high pressure water mist fire suppression in subway train. The experiment is conducted in half scale modeled train of a steel-welled enclosure (8.0m*2.4m*2.1m). The ventilation velocity is controlled by the ventilation duct through an inverter in the range of 0 to 2 m/s. The coverage-radius and an injection angle of an high pressure water mist system are measured. The mist nozzle with 7-injection holes is operated with pressure 80 bar. The heptane pool fires are used. The fire extinguishment times and the temperatures are measured for the ventilation velocities. In conclusion, because the momentum of injected water mist is more dominant than that of ventilation air, the characteristics of water mist, the fire extinguishment times and the temperatures are affected very little by ventilation velocity.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.66-72
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• 2008

In this study, transient 3D numerical simulations were performed to analyze the characteristics of fire driven flow for smoke ventilation system operating conditions in the deeply underground subway station. The smoke flow patterns were compared and discussed under smoke fan operating mode and off mode in the platform. Soongsil Univ. station(line number 7)was chosen for simulation which was the one of the deepest underground subway stations in the each lines of Seoul. The geometry for model is 365m in length include railway, 23.5m for width, 47m for depth. Therefore 10,000,000 structured grids were used for fire simulation. The parallel computational method for fast calculation was employed to compute the heat and mass transfer eqn's with 6 CPUs(Intel 3.0GHz Dual CPU, 12Cores) of the linux clustering machine. The fire driven flow was simulated with using FDS code in which LES method was applied. The Heat release rate was 10MW and The Ultrafast model was applied for the growing model of the fire source.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.527-539
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• 2018

The subway used by many passengers is required to maintain a safe and comfortable environment and PSD (Platform Screen Door) must be installed in the platform after reinforcing the standard in 2003. In the previous research, in case of subway fire to control it, it is necessary to design the optimal ventilation and smoke exhaust system according to equipment capacity of the smoke exhaust system. Therefore, in this study, based on the results of previous research, three-dimensional numerical analysis was performed for the CO gas and smoke flow by the subway ventilation system in case of platform fire. As a result of this study, it was found that in case of emergency, if only the upper-level smoke exhaust system is activated, the risk of evacuation is high due to CO gas (653.8 ppm) and smoke concentration ($768.4mg/m^3$). And when all the smoke exhaust systems are activated and only the fire side PSD is opened, CO gas (36.0 ppm) and smoke concentration ($26.2mg/m^3$) are detected and the propagation range of smoke flow was reduced. When all the smoke exhaust systems are activated and only the fire side PSD is closed, it was analyzed as the most effective ventilation mode in the evacuation environment due to the absence of smoke-recirculation.

• Fire Science and Engineering
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• v.17 no.3
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• pp.7-12
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• 2003

A 50 kW polyurethane fire in a compartment of 4 m ${\times}$ 1 m ${\times}$ 1.5m with large openings similar to a subway station was simulated by a large eddy simulation to investigate the fire and smoke control. The NIST FDS, which employed a mixture fraction combustion model and a finite volume method for radiation, was utilized. Distribution of temperature and smoke particles was compared with in the lower and upper corridors for three different smoke control systems, ventilation, purge, and extraction, starting in 5 sec from the ignition of the fire. For the given geometries, the ventilation system showed the best smoke removal rate and lowest temperature distribution in the both corridors. It was confirmed that the purge system is not recommended for a subway station since the smoke removal rate of the purge system was worse than that without a smoke control system.

• 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.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.2195-2201
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• 2010

High concentration of carbon dioxide in subway cabin may cause various adverse effects on the passengers. Because carbon dioxide is produced by breathing of passengers, carbon dioxide concentration at rush-hours is extremely high. In most cases, the ventilation is not that easy for subway cars due to the high concentration of dust in tunnels. In this study, more practical way to control carbon dioxide in subway car was suggested. The decrease of carbon dioxide concentration was observed when the system was applied to a real subway car. The regenerative method for maintenance-free carbon dioxide control system was also suggested.

• Journal of Fisheries and Marine Sciences Education
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• v.22 no.4
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• pp.604-610
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• 2010

Busan subway transportation system has been established a key role in the society last 20 years. However many people are suffering from hot and humid environment at subway station and platform due to deteriorated ventilation system as well as insufficient air conditioning system in existing stations and platforms. As a result, these systems require revitalization. There is about 5400tons of low temperature underground water is generated from subway stations every day. By using this method and air washer we are trying to lower the temperature. Air washer is commonly used for removing humidity but in this experiment it will be used as air precooling. This research offers result of experiment using air washer system to lower the temperature in large spaces like subway station. The experiment result has shown when L/G was the same, at condition which water spray temperature at $18^{\circ}C$ resulting inlet and outlet temperature difference larger. Also, in the same water spray temperature conditions, larger L/G condition showed a greater temperature difference. LCC evaluation of both system were shown that air washer system of using underground water will save 53% of the initial cost than refrigeration system, and save 75% of operating cost.

• Fire Science and Engineering
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• v.22 no.1
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• pp.61-67
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• 2008

This study is focused on the numerical predictions of heat and smoke exhaust characteristics in an underground subway station stopping a fire train. Various ventilation operating modes with the fan equipped the platform and tunnels are considered. Distributions of temperature, carbon monoxide and visibility at a height of 1.7 m(breath height) above the platform are analysed for different ventilation fan operation mode. The numerical results show that smoke and heat is rapidly removed through tunnel by operating the tunnels fans. We suggested that during evacuation of passengers is not completed, the ventilation system in the platform is activated. After completion of passenger evacuation tunnel fans are activated but the fans in the platform are stopped.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.2
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• pp.153-161
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• 2008

The guidelines for indoor air quality of public transportations such as subway, train and bus was presented by Korean Ministry of Environment last end of year 2006 based on the great consequence of indoor air quality in daily life. Two main parameters, carbon dioxide($CO_2$) and particulate matters smaller than $10\;{\mu}m(PM_{10})$, were selected as index pollutants for the management of indoor air quality. The former pollutant, $CO_2$, is regarded as index of ventilation status and the major source of $CO_2$ in the train or subway is the exhalation of passengers. It is publically perceived that the high $CO_2$ concentration in a crowded subway will be reduced and ventilated with outdoor air by door-opening taken every 2 or 3 minutes when the train stops each station. However, there has not been any scientific proof and quantitative information on the effect of door-opening on the $CO_2$ reduction by ventilation with outdoor air. In this study, $CO_2$ concentration and number of passengers were measured at each station on the 3 lines of Korail metropolitan subway. In order to evaluate the effect of $CO_2$ reduction by door opening, the theoretical approach using the $CO_2$ balance equation was performed. By comparing the predicted data with monitoring one, the optimum $CO_2$ dilution factor was determined. For the first time, it was quantified that about 35% of $CO_2$ concentration in the subway indoor was removed by the door-opening at each station.