• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.144-150
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• 2013

This paper presents an analysis of door design for the Ui LRT based on experiments to predict doorway flow-time and their analyses results. A similar railway vehicle (from Gimhae LRT) and operational conditions are utilized to assess the doorway flow-time through repetitive experiments. Design of the experiments consists of four scenarios, and the experiments are repeated 39 times in total. We use the results of the experiments to verify the design of doors of Ui LRT (e.g. the required number of doors and their width). Various statistical analyses are carried out for the flow-time with respect to the number of boarding/alighting passengers. We make three category levels of boarding/alighting passengers, and analyze the mean and variance for each category, and then carry out One-Way ANOVA to analyze how the number of boarding/alighting and onboard passengers impact flow-time. The results of this paper can be used for making decisions about doors of the LRT vehicle.

• Fire Science and Engineering
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• v.27 no.2
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• pp.75-79
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• 2013

The present study measured the light transmission to quantify the smoke density(smoke mass concentration) through the doorway in a compartment fire and performed the uncertainty analysis to evaluate the reliability of the measurement technique. The optical light extinction method based on Bourguer's law was applied to estimate the smoke density of doorway exhausting smoke flow in upper layer of a compartment for methane gas fires. The measurement uncertainty of the light extinction measurement was evaluated for the light transmittance, path length, and specific mass extinction coefficient and the expanded uncertainty was estimated about 20% with confidence level of 95%. The mean smoke density through the doorway for the methane fire was calculated for quasi-steady fire and the smoke density linearly increased as the GER increased.

• 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.

• Journal of the Korean Society of Combustion
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• v.15 no.3
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• pp.32-39
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• 2010

An experimental study was conducted to investigate the relationship between global equivalence ratio(GER) and fire characteristics in an ISO 9705 room. Heptane fuel was burned with different fuel flow rates and doorway widths in order to force the room to be placed in different GER conditions. It was observed that after the onset of under-ventilated fire conditions, temperature and unburned fuel components such as CO and soot increased with increasing heat release rate (HRR), regardless of the doorway width. From the analysis of local mixture fraction, it was reconfirmed that the inclusion of soot production in the product composition was very important to predict accurately the chemical conditions inside the compartment, particularly for the under-ventilated fire conditions. In addition, the local equivalence ratio (LER) was directly proportional to the GER with a unit gradient regardless of doorway width when the soot production was included in the chemical products. This finding provided an important potential that the GER could be used to correlate the local thermal and chemical environment measured at the upper layer of a full-scale enclosure when soot was included.

• Journal of Mechanical Science and Technology
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• v.16 no.11
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• pp.1485-1496
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• 2002

In order to investigate the fire-induced smoke movement in a three-dimensional room with an open door, numerical and experimental study was performed. The center, wall, and corner fire plumes for various sized fires were studied experimentally in a rectangular pool fire using methanol as a fuel. The numerical results from a self-developed SMEP (Smoke Movement Estimating Program) field model were compared with experimental results obtained in this and from literature. Comparisons of SMEP and experimental results have shown reasonable agreement. As the fire strength became larger for the center fires, the air mass flow rate in the door, average hot layer temperature, flame angle and mean flame height were observed to increase but the doorway-neutral-planeheight and the steady-state time were observed to decrease. Also as the wall effect became larger in room fires, the hot layer temperature, mean flame height, doorway-neutral-planeheight and steady-state time were observed to increase. In the egress point of view considering the smoke filling time and the early spread of plume in the room space, the results of the center fire appeared to be more dangerous as compared with the wall and the corner fire. Thus it is necessary to consider the wall effect as an important factor in designing efficient fire protection systems.

• Fire Science and Engineering
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• v.28 no.6
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• pp.35-40
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• 2014

Bottleneck occurs as many people crowd into narrow doorway or corridor. Delaying egress time is occurred by bottleneck effect, and it is very important phenomenon on the egress analysis for building fire. An analysis of egress time should includes flow rate for considering bottleneck. Flow rate is numbers of people who pass the narrow gate as door or start point of corridor per unit length and unit time. The flow rate resulted from egress modeling should be approached to the result of experiments. In this study, flow rates from modeling by 'Pathfinder' and experiments was compared. The difference between the result from egress modeling and the one from experiments was verified. The average value of experiments is $4.25N/m{\cdot}s$, and the maximum average value of modeling is $1.55N/m{\cdot}s$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.11
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• pp.806-812
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• 2012

Air curtains are widely used in commercial and public buildings to replace solid doors where traffic of people is predicted. At doorways where the solid door is open continuously or intermittently, an air curtain may be installed in order to reduce the flow of heat and moisture from the enclosed space to the outside. The purpose of this paper is to predict isolation performance of the single-sided air curtain when the wind is blowing. For the study, a numerical simulation is used to find the influence of various jet velocities on the efficiency of the single-sided air curtain device which is mounted at the side of the doorway. The isolation performance of the single-sided air curtain is evaluated by sealing efficiency which provides the assessment of the infiltration air ratio. According to the result of this study, the single-sided air curtain has lower sealing efficiency than downward-blowing air curtain. Therefore, for energy conservation in heating space, the single-sided air curtain is not recommended because of its low effectiveness.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.1
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• pp.41-48
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• 2009

The present study has been performed to investigate the thermal characteristics of under-ventilated compartment fire which is a typical fire condition in structures. A series of fire experiments was conducted to characterize the thermally driven flow in a 2/5 scale ISO 9705 fire compartment. Three different fuels were used in this test series, methane gas, heptane pool, and polystyrene pellets fire. In order to measure accurate temperature, double shield aspirated thermocouples reducing the effect of radiative energy exchange on temperature measurement were used in addition to bare bead thermocouples. The upper layer temperature for well ventilated fire was increased with increasing heat release rate, but it was slightly decreased for under-ventilated fire. The measured temperatures in the upper layer at the front sampling location were higher than at the rear. Thermal characteristics through the doorway were also analysed for a wide range of heat release rates. This study provides a comprehensive and quantitative assessment of fire behavior for under-ventilation condition of fire.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.5
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• pp.703-709
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• 2002

In order to investigate the smoke movement in three dimensional room fires, the center fire, wall fire and corner fire plume in different sized fires were studied experimentally by rectangular pool fire using methanol as a fuel. As the fire size became larger for the center fires placed at the center of the floor, the air flow rate entrained through the opening, average hot layer temperature, flame angle deflected backwards and mean flame height was observed to increase. On the other hand, as the fire size became smaller, the neutral plane height in the door and time reached steady-state was observed to decrease. The average hot layer temperature, mean flame height and doorway neutral plane height obtained from comer fire were higher than those produced by wall fires and center fires. The simple model for describing the effect of walls on the mean flame height was presented. It was shown that the model provides a good description of the present measurements, when used with the assumption by Hansell(1993), that the increase of the average flame height is equal to the ratio of the open to the total perimeters of the trays. Also the two models for predicting the effects of walls on the mean flame height were presented. These models overestimated the measured values of the mean flame height above fuel trays close to a wall and in a corner by approximately 19-26%, respectively.

• Fire Science and Engineering
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• v.24 no.5
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• pp.32-38
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• 2010

Multi-dimensional fire dynamics were studied numerically with the change in ventilation conditions in a full-scale ISO 9705 room. Fire Dynamic Simulator (FDS) was used for the identical conditions conducted in previous experiments. Flow rate and doorway width were changed to create over-ventilated fire (OVF) and under-ventilated fire (UVF). From the numerical simulation, it was found that the internal flow pattern rotated in the opposite direction for the UVF relative to the OVF so that a portion of products recirculated to the inside of compartment. Significant change in flow pattern with ventilation conditions may affect changes in the complex process of CO and soot formation inside the compartment due to increase in the residence time of high-temperature products. The fire behavior in the UVF created complex 3D characteristics of species distribution as well as thermal and flow structures. In particular, additional burning near the side wall inside the compartment significantly affected the flow pattern and CO production. The distribution of CO inside the compartment was explained with 3D $O_2$ distribution and flow patterns. It was observed that gas sampling at local positions in the upper layer were insufficient to completely characterize the internal structure of the compartment fire.