• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.135-141
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• 2004

The present paper concerns a smoke movement in a tunnel fire with a vertical shaft. The model tunnel measured 13.4m long, 0.4m wide and 0.4m high. The cross section is 1： 20 of a full scale tunnel. Ethanol was used as a fuel. The fire size in model tests varied from 1.35 kW to 13.37 kW, which corresponds to full scale fires of 2.41 to 23.91 MW. Smoke front velocity and temperatrue were decreased due to the vertical shaft install. Temperature was reduced maximum about 2$0^{\circ}C$ at ceiling and about 23$^{\circ}C$ at vertical position. CO concentration was reduced as the vent width widened. When vent width was more than 15 cm, CO concentration was not reached 100 ppm. Descent degree of the smoke layer was confirmed through the visualization.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.3
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• pp.216-222
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• 2011

Recently, hybrid air-conditioning system has been proposed and applied to achieve building energy saving. One example is a system combining radiation panel with natural wind-induced cross-ventilation. However, few research works have been conducted on the non-uniformity of thermal comfort in such hybrid air-conditioning system. In this paper, both thermal environment and non-uniform thermal comfort of human thermal model under various air-conditioning system, including hybrid system, were evaluated in a typical office room using coupled simulation of computation fluid dynamics, radiation model and a human thermal model. The non-uniformity of thermal comfort was evaluated from the deviation of surface temperature of human thermal model. Flow fields and temperature distribution in each case were represented.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2001.05a
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• pp.63-68
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• 2001

In wide angle diffuser, the cross-sectional area increases so rapidly that separation can be avoided only by using boundary layer control. In this study, an experimental and numerical study is performed on performance of a diffuser with guide damper. A series of measurements were carried out to investigate the characteristics of diffuser for different divergence angle(${\phi}=7^{\circ}, \;10.5^{\circ}\;and\; 14^{\circ}$) of guide damper and angle of ${\phi}=10.5^{\circ}$ was through to be the best among three cases. Judging from the results, guide damper can be used as an effective means of improvement for diffuser performance.

• Korean Journal of Veterinary Service
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• v.38 no.3
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• pp.195-198
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• 2015

Mannheimia haemolytica is an opportunistic bacterium that is widely recognized among the bovine respiratory disease (BRD) complex in cattle. Five Hanwoo with a history of fever, anorexia and dyspnea were died within 2 days in a the middle of summer. Four cattle were pregnant. The cattle house were located in mountainous area but the window for air ventilation was open only one side. In addition, the fecal material for fermentation was located indoor. Air ceiling fan did not work. The indoor temperature was $40^{\circ}C$. After working on air fan, the indoor temperature was still $36^{\circ}C$. On necropsy, there was fibrinous pleuritis with a rich yellowish pleural fluids in the thorax. The cross-section of the lung showed lobar fibrinonecrotic pneumonia with expanded interlobular septa by edema and fibrin. Microscopically, parenchymal necrosis with dense layer of inflammatory cells were observed surrounding interlobular septum. Fibrin and inflammatory cells were filled in the alveoli. Bacteriological cultures of pulmonary tissue showed growth of M. haemolytica. This pneumonia case in Hanwoo suggests that environmental stressors such as high temperature, insufficient air ventilation, and pregnancy be the cause of mannheimoisis. Control of environmental stressor, such as temperature indoor is necessary to prevent BRD caused by M. haemolytica.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.100-107
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• 1997

In case of a fire outbreak in a uni-directional road tunnel, the flow of traffic immediately behind the fire disaster will be stalled all the way back to the entrance of the tunnel. Furthermore, when the vehicle passengers try to flee away from the fire toward the entrance of the tunnel, the extremely hot fume that propagates in the same direction will be fatal to the multitudes evacuating, but may also cause damage to the ventilation equipments and the vehicles, compounding the evacuation process. This paper will present the 3-dimensional modelling analysis of the preventive measures of such a fume propagation in the same direction as the evacuating passengers. For the analysis, the fire hazard was assumed to be a perfect combustion of methane gas injected through the 1 m X 2 m nozzle in the middle of the tunnel, and the product of $CO_2$ as the indicator of the fume propagation. From the research results, when the fire hazard occurred in middle of the 400 m road tunnel, the air density decreased around the fire point, and the maximum temperatures were 996 K and 499 K at 210 m and 350 m locations, respectively, 60 seconds after fire disaster occurred, when the fumes were driven out only towards the exit-direction of the tunnel. By tracing the increase of $CO_2$ level over 1% mole fraction, the minimum longitudinal ventilation velocity was found to be 2.40 m/sec. Furthermore, through Analysis of the temperature distribution graphs, and observation of the cross-sectional distribution of $CO_2$ over 1% mole fraction, it was found that the fume did not mix with the air, but rather moved far in a laminar flow towards exit of the tunnel.

• Korean Institute of Interior Design Journal
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• v.18 no.6
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• pp.104-114
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• 2009

The purpose of study was understanding necessity of environment design for underground parking lot in residential design plan and grasping design plans of 'Activity Support' that considerate women, exclude women's unsecured feeling at underground parking lot. The inquiry analyzed 6 design plan in design competition that considerate women according to precede studies, a theory of CPTED, a design guide for wayfinding, and survey. A ramp, circulation, entrance, lighting, ventilation, and space design plan are proceed on this study The result are as below. First, a rectilinear figure ramp suits entrance plan on the circulation, but if it is not possible, cross-using of rectilinear and curvilinear figure ramp plan is desirable. Second, on the circulation plan, vehicles circulation plan and equality parking distribution plan got accomplished generally, and help senses of direction because it is planed network systemize. On a large scale underground parking lot, simplify parking circulation to convenience entrance and exit for weak in sense of direction. Third, the shape and material that‘s environmentally conscious will be in use to the entrance plan. As the first stage to the underground, artwork that women prefer can modulate the rejection of underground space. Forth, natural lighting system and ventilation can make the environment-friendly space, decrease the women’s rejection to the underground, it can also keep a natural watch on the space. Fifth, on the space design plan, it can use bright and comfortable design of wall and ground to decrease the women‘s rejection, also it is useful to the sense of direction. LED indirect lighting plan that 58.7% of women prefers on survey reflects women’s state of desire that bright and atmosphere. In addition, proper use of plans that subsidiary facilities, rest area with Sunken, and nature-friendly material can minimize differences of underground and ground parking lot.

• Journal of Oral Medicine and Pain
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• v.35 no.3
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• pp.193-202
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• 2010

The purpose of this study was to determine the sites of narrowing/obstruction and to measure the regional severity of narrowing through the evaluation of dynamic changes in upper-airway of healthy subjects. The selected 9 subjects were proved not to have any sleep-related disorder such as snoring or obstructive sleep apnea through clinical examination, radiological examination, sleep study with a portable recording system. Afterward, the Electron Beam Tomography was performed during the waking and sleeping state of subjects, with their mandible in resting and protruded position. Intravenous injection of Dormicum$^{(R)}$ was used for the induction of sleep. The maximum and minimum cross-sectional areas at each airway level during tidal ventilation were measured and the Collapsibility Index for each level of cross-section was also computed. In a comparison with results under variable conditions, the result was showed that the significant difference between each airway level divided with upper, middle, lower region of upper airway is not observed in the average minimum cross-sectional areas and Collapsibility Index. The significant difference only between in wake and sleep state was observed in the average minimum cross-sectional area at the lower region. Also, in wake state, the significant difference between resting and protrusive position of mandible for the average minimum was also observed in cross-sectional area at middle region. In sleep state, no significant difference between resting and protrusive position of mandible was observed in cross-sectional area and the Collapsibility Index.

• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.5
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• pp.563-574
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• 2020

Currently, road tunnels and railroad tunnels are building smoke control systems to emit toxic gases and smoke from fires. Among the various smoke control systems, the transverse smoke control system has the disadvantage that air supply or exhaust is performed on only half of the cross-section, rather than air supply or exhaust on the entire cross-section of the tunnel as air is supplied or exhausted by partitioning the wind path. Therefore, this study analyzed the effect of exhaustion through numerical analysis and scaled model tests on the zoning smoke control system, which improved the limitations of the transverse smoke control system. As a result of the scaled model test, the transverse ventilation system exhibited a 25.6% smoke control rate based on the state where no smoke was controled, and zoning smoke control system showed a smoke control rate of 40.8%. In addition, as a result of numerical analysis, it was found that transverse ventilation system did not control fire smoke spreading from the tunnel and continued to spread. On the other hand, zoning smoke control system was found to be smoke controled within a certain section due to the air curtain effect and the flue gas effect.

• Tunnel and Underground Space
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• v.28 no.1
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• pp.111-124
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• 2018

The purpose of this study is to analyze ventilation design factor for network-type double-deck road tunnel that have been developed actively around the world. A numerical analysis was carried out through computational fluid dynamics (CFD) to derive shock loss coefficient that occurs due to the change in cross sectional area at both merging section and diverging section. The model used for the numerical analysis is real-scale model and the reliability of the result is secured by comparing with the coefficient of the previous studies. As a result of this study, shock loss coefficient was calculated depending on the change in cross-sectional area ratio and was higher than the result of previous studies in case of both merging section and diverging section. It is considered that the characteristics of the geometrical structure of network-type double-deck road tunnel have a great impact on shock loss coefficient. Therefore, the result of this study is expected to be helpful for more accurate ventilation design of network-type double-deck road tunnel.

• Korean Institute of Interior Design Journal
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• v.23 no.3
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• pp.173-180
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• 2014

Dwelling connotes characteristics like social and cultural and technical climatic conditions, lifestyles and demands of regions, and especially, apartment, as one of dwelling types, shows various aspects of modern society. With the economic development centering on large cities, apartments have been established as universal housing forms in Seoul and Shanghai. The deepening of economic development in cities has increased small households consisting of one or two persons by affecting the population and household structure, and they've become information consumer groups. This has also influenced the size of apartment and increased the demand for small-sized housing. If the floor area is small, it is possible to use space widely according to the plan composition, so there is a need for floor planning to understand natural environment, physical environment and residents.This study compared and analyzed plan compositions of small-sized apartments which have been parceled out for the recent three years in Seoul and Shanghai. This study aims to understand housing cultures and users in the two countries depending on natural environments, living habits and spatial functions by analyzing common points and differences of public spaces like living room, dining room and kitchen, and private spaces like bedroom which have absolute effects on room arrangement and traffic line. The study results are as follows. From the perspective of natural environments, in Seoul, two-sided open cross-ventilation structure where is favorable to lighting and ventilation, occupied the biggest proportion of public space, while in Shanghai, most public spaces had lighting and ventilation structures through windows in each room. In Seoul, 3R type occupied the largest proportion of private space(87.7%), and privacy was maintained and space scale was adjusted using spaces with diverse functions such as bathroom in the couple bedroom, dress room and powder room and variable walls. But 2R type occupied the largest proportion of private space(60.2%) in Shanghai, and they emphasized private space and privacy of each room depending on major living habits. In conclusion, this study for comparing and analyzing common points and differences of small-sized apartment plan compositions in Seoul and Shanghai will provide proper guidelines for small-sized apartments to be built in Seoul and Shanghai in the future, if strong points and weak points of plan compositions in the two countries will be additionally analyzed and remedied.