• Journal of Korean Tunnelling and Underground Space Association
• /
• v.12 no.1
• /
• pp.43-49
• /
• 2010

The escape connecting gallery in a tunnel on a road is one of emergency equipment to ensure safety for passer in the tunnel against the tunnel fire. Government stipulate over 500m tunnel has the cross passage at intervals of less then 250 m. However, this lump estimated interval is generated the concerns of exaggeration and under construction because peculiarity of the tunnel ex. The velocity of the tunnel airflow, an incline, degree of a fire, and innering area are not considered. The study indicate the way to estimate of the cross passage considered an incline and the velocity of the tunnel airflow for efficient application of cross passage on the tunnel design. As a result, in 0.0 m/s and 1.0 m/s of the velocity of the tunnel airflow case, the movement of smoke is influenced by the incline however, in 20 m/s case, it isn't influenced by incline much. According to the velocity of tunnel airflow and the incline, optimum interval of cross passage is not corresponded. Therefore established lump estimate that has 250 m intervals would be changed to estimate of optimum interval of cross passage that considered about the properties of tunnel, the velocity of the tunnel airflow, incline, degree of a fire and innering area of the tunnel.

• Journal of the Korean Geographical Society
• /
• v.51 no.1
• /
• pp.23-40
• /
• 2016

In this study, long-term changes in means and extreme events of precipitation during summer rainy period called Changma (late June~early September) are examined based on rainfall data observed by Chukwooki during Joseon Dynasty (1777~1907) and by modern rain-gauge onward (1908~2015) in Seoul, Korea. Also, characterizations of the relevant changes in synoptic climate fields in East Asia are made by the examination of the NCEP-NCAR reanalysis I data. Analyses of 239-year time series of precipitation data demonstrate that the total precipitation as well as their inter-annual variability during the entire Changma period (late June~early September) has increased in the late 20th century and onward. Notably, since the early 1990s the means and extreme events during the summer Changma period (late June~mid-July) and Changma break period (late July~early August) has significantly increased, resulting in less clear demarcations of sub-Changma periods. In this regard, comparisons of synoptic climate fields before and after the early 1990s reveal that in recent decades the subtropical high pressure has expanded in the warmer Pacific as the advection of high-latitude air masses toward East Asia was enhanced due to more active northerly wind vector around the high pressure departure core over Mongolia. Consequently, it is suggested that the enhancement of rising motions due to more active confluence of the two different air masses along the northwestern borders of the Pacific might lead to the increases of the means and extreme events of Changma precipitation in Seoul in recent decades.

• Journal of Korea Multimedia Society
• /
• v.15 no.5
• /
• pp.672-676
• /
• 2012

This investigation relates generally to windows and doors for traditional Korean houses(Hanok) and, more particularly, to windows and doors for traditional Korean houses which have a lattice structure that can minimize heat loss in the winter. In order to accomplish the above objective, the present invention provides a door for traditional Korean houses, including a structure of a lattice door framed with vertical lattice frames and horizontal lattice frames which are arranged in a regular periodic pattern.

• Journal of the Semiconductor & Display Technology
• /
• v.10 no.1
• /
• pp.1-6
• /
• 2011

In this paper, the air flow induced by the rotating flat disk is numerically investigated in a hope to better understand the air flow structures inside the wax spin coater for a silicon wafer polishing station. Due to the complex inner geometry of actual spin coater such as the casing around the rotating ceramic block and servo motor, recirculation of air flow is inevitably found on the coating target if the internal space of spin coater is closed at the bottom and it could be the possible source of contamination on the wax coating. By numerical flow simulation, we found that it is necessary to install the air vent at the bottom and to apply the sufficient air suction in order to control the path of air flow and to eliminate the air recirculation zone above the spinning surface of coating target.

• Solar Energy
• /
• v.19 no.4
• /
• pp.71-80
• /
• 1999

For developing a new measuring device which enables the thermal resistance at comers of the building envelope in addition to the plate wall measuring device, computer simulations were performed to clarify the problems produced during previous tests. For the optimum design to reduce the temperature deviation in measuring device, the specifications of the measuring devices are to be as follows : Dimension of the device is $500{\times}500{\times}100mm$ in size, heating plate is seperated to some degree from the inner surface of the measuring device, lower temperature of heating plate is as effective as possible, fans should be located at the upper part in the measuring device and face to downward.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.1
• /
• pp.6-11
• /
• 2009

Flow field in a roller conveyor system, induced from the movement of a cassette in which glasses for flat panel display are loaded, is numerically studied in this paper. Contamination on the glass surface by dust particles produced from mechanical friction between roller and cassette is predicted from the analysis results of flow fields. Results show that a large swirl flow is formed under the moving cassette with constant speed. This swirl flow is confined only under the cassette because two main streams from the backward and the fan filter unit on the top ceiling are sufficiently strong. Therefore, it can be said that possibility of the contamination by the particles originated from the friction is relatively low. It is also revealed that flow direction between glass plates is changed according to the speed of the cassette movement due to the shear force of glass plates.

• Fire Science and Engineering
• /
• v.32 no.5
• /
• pp.34-39
• /
• 2018

In this study, the experiment conditions for the variation of heat release rate in compartment space were constructed to analyze the effects of fire spread and the operation time of sprinkler in accordance with the heat loss of the sprinkler's heat element. The compartment composed of fire board (width = 0.3 m, height = 0.5 m, length = 3.0 m), are manufactured to measure the temperature distributions in the inner space, the mass loss rate and heat release rate during the experiment of N-heptane pool fire test. Also, the operation time of sprinkler is analyzed with the installation of sprinkler and C-factor using Fire Dynamics Simulator Ver.6 under the experiment conditions. The results show that the operation time of sprinkler, which has RTI $100(m{\cdot}s)^{0.5}$ operating temperature $70^{\circ}C$, is 30 s~60 s for C-factor = 0 and 1, 62 s~92 s for C-factor = 3, and 120 s over for C-factor = 5, respectively.

• Journal of Korean Society of societal Security
• /
• v.4 no.1
• /
• pp.29-37
• /
• 2011

Recently, Inhabitants nearby the high embankment road have requested a civil complaint on the environmental deteriorations and economic harms. This study was carried out numerical simulation using the 3-D microclimate model 'Envi-met' in order to investigate the variations of a flow field and a temperature field at the road sections with a high embankment and a bridge. About the simulation of flow field, the wind field has changed due to the disturbance of airflow by a high embankment road considerably. And the wind velocity decreased in the whole of simulation space widely. But, the wind velocity and wind direction sited loose to the section of a bridge, relatively. In the results of a temperature field, the slight variations of temperature field were discovered by the disturb of the mixing flow from a high embankment road. These results indicate that the numerical simulation can provide useful information to minimize the disasters, such as traffic accidents and various microclimatic environments in the transportation projects.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.11
• /
• pp.5384-5391
• /
• 2011

The computational fluid dynamics was analyzed for the pressure distribution, stream velocity distribution, stream line field, retention time and temperature distribution which are applied to the catalyst layer in the RCO reactor to derive the optimum operating condition of the heat condensing type catalytic oxidation (RCO) reactor. The results from the computational analysis revealed that the pressure loss due to the ceramic honeycomb in the catalytic bed of the reactor which is operating currently is not significant and the stream velocity (1.8~2.7 m/s) after the ceramic filter is working in stability without big channeling. To improve the stream velocity distribution of the air stream, it is necessary to extension of the connecting range between the plenum and catalytic bed inside the facility. However, the method of attaching the air stream guide vane or the perforated plate inside the reactor was not so effective.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2003.07a
• /
• pp.402-406
• /
• 2003

묘생산 시스템은 크게 개방형과 폐쇄형으로 구분된다. 개방형 묘생산 시스템은 시스템 내부와 외부의 공기ㆍ물ㆍ열 등의 교환이 가능한 시스템을 의미한다. 현재 실생묘, 삽목묘, 접목묘 등은 일사가 투과되는 온실 또는 묘포장에서 생산된다. 그러므로 온실 또는 묘포장을 이용한 묘생산 시스템은 개방형 묘생산 시스템에 해당한다. 개방형 묘생산 시스템에서는 외부기상의 변동에 따라 시스템 내의 기온, 상대습도, 광량, 기류속도, $CO_2$ 농도 등의 물리적 환경요인이 변화하므로 이들 환경 요인을 일정한 수준으로 제어하기가 쉽지 않다. 때문에 균일한 묘소질을 지닌 묘의 계획적 생산이 근본적으로 불가능하다. (중략)