• 한국생산제조학회지
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• 제25권6호
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• pp.434-439
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• 2016

Optical fiber splice closure serves to protect connection parts from external environment. Moreover, it functions as a connection, junction, and distribution in diverse surroundings such as aerial, underground, duct, and pole. In this research, first, the optical fiber splice closure, its configuration, and the design problem were briefly investigated. Second, the design and application for in-line cable closure were studied to satisfy its construction and technical features. The injection molding conditions and optimal design were conducted to save time and cost during the manufacturing process. Third, methods to minimize loss via of optical fiber cable while strongly fixing optical fiber cable with optical cable holder to prevent fracture were researched, and tests such as perfect air tightness and mechanical and environmental performance were conducted.

• 터널과지하공간
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• 제4권2호
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• pp.192-200
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• 1994

Underground offers many advantages for storing agricultural and marine products. Since it is confined by thick walls of rock it is easy to control temperature and humidity and to achieve air and water tightness. Also, damages by rodents and insects could be avoided. Flexibility in choosing the location is another advantage that underground could offer. Consequently the goods could be stored near the big city to meet the demand change. Because of these advantages, many underground food storage facilities were built and operated successfully in U.S. and many Euroupean countries. On the other hand, there is no underground food storage facilities in Korea despite the need is growing rapidly. This paper describes the case studies of foreigh food storage and technologies related to food storage were analyzed and evaluated. Also performed is analysis of domestic technologies for construction and operation of underground food storage facilities to deduce the fields of studies that have to be conducted.

• 설비공학논문집
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• 제20권4호
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• pp.274-279
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• 2008

In the perspective of saving energy in buildings, high performance of insulation and air tightness for improving the heating and the cooling efficiency has brought the positive effect in an economical view. However, these building energy saving technologies cause the lack of ventilation, which is the direct cause of increasing the indoor contaminants, and it is also very harmful to residents because they spend over 90% of their time in the indoor area. Therefore, the ventilation is important to keep indoor environment clean and it can also save energy consumption. In this study, a HEPA type breathing wall is designed as a passive ventilation system to collect airborne particles and to supply fresh outdoor air. To make fine porous structures, polymer nano fibers which were made by electro spinning method are used as a precursor. The nano fibers are coated with SiO2 nano particles and finally the HEPA type breathing wall is made by sintering in the electric furnace at $300\sim500^{\circ}C$. The pressure drops of nano ceramic structure are 8.2, 25.5 and 44.9 mmAq at the face velocity of 2.0, 5.9 and 8.8 cm/s, respectively. Also the water vapor permeability is $3.6g/m^2{\cdot}h{\cdot}mmHg$. In this research, the porous nano ceramic structures are obtained and the possibility for the usage of a material for HEPA type breathing wall can be obtained.

• 한국산학기술학회논문지
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• 제20권9호
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• pp.175-181
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• 2019

수소연료전지차(FCEV)의 수소연료 공급시스템에서 대용량 감압에 사용되는 기존의 1단 감압 구조 레귤레이터(Regulator)의 경우 높은 감압에 따른 맥동과 느린 응답, 수소 취성, 누설, 고중량, 고비용 등의 문제점이 있다. 이러한 문제점은 2번에 걸친 감압 메커니즘(2단 구조)을 가지는 2단 레귤레이터 개발을 통해 극복될 수 있으며, 2번째 감압시점에 전자식 솔레노이드 밸브를 적용한다면 폭넓은 출구압력의 제어가 가능하다. 이에 따라 2단 전자식 솔레노이드 밸브를 가지는 레귤레이터의 출구압력 정밀도 향상과 누설방지, 내구성, 경량화, 가격저감 등의 기술개발이 필요한 실정이다. 이중에서도 레귤레이터의 필수적인 성능인 출구압력 정밀도 향상과 누설 방지를 위해 감압 전과 감압 후의 구조부분을 나누어 각각의 초기 내압 적용 후 Valve part가 닫힌 상태(Open Ratio : 0 %)로 가정하여 해석 연구를 진행하였다. 1차감압부의 기밀성과 관련하여 Aluminum Alloy 소재의 사용은 부적절하다고 판단되었고, 서로 다른 금속으로 구성되었을 때는 응력의 변화와 함께 변위 또한 같이 증가하므로 이종 소재를 사용하는 접촉부 구성은 부적절하다고 판단되었다. 2차 감압부의 기밀성과 관련된 변위 측면에서는 Young's Modulus 값이 큰 TPU(Thermoplastic Polyurethane)를 사용하는 것이 비교적 변위량이 작으므로 적절하다고 판단하였고, 기밀성에 대한 기준으로 Case 분석을 진행한 결과 최적 형상을 설계할 수 있었다.

• 한국산학기술학회논문지
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• 제21권12호
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• pp.782-789
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• 2020

국내에서 제작되는 철도차량의 해외 시장 개척을 위하여 다양한 기후환경에서도 최고의 성능을 유지하기 위한 철도차량의 기술개발이 시급하다. 본 연구에서는 혹독한 기후환경시험 모사 시스템 구축에 필수적으로 적용되어야 할 국제·국내 규격을 조사 및 비교 분석하였으며, 국내 규격의 향상 방안을 고찰하였다. 기후환경시험 풍동내에서 풍속 및 온도 규정은 UIC, EN 및 IEC 규격에 규정되어 있으며, EN 50125-1에서 가장 큰 풍속인 180km/h까지 시험하도록 되어있다. 극저온 시험은 UIC 및 EN 규격에서 가장 낮은 온도 -45℃를 제시하고 있으며, IEC 62498-1에서 55℃까지의 고온시험을 규정하고 있다. 태양광 복사 시험은 UIC, EN, IEC 규격에서 최대 1200W/m2 복사 강도까지 규정되어 있다. 강우시험은 IEC, EN 및 KS R 9145 규격에서 규정하고 있으며 살수량, 살수 압력 및 살수방법 등에서 차이점이 있다. 강설시험의 경우는 국내외적으로 상세히 규정되어 있지 않다. 여압 시험은 KRTS-VE-Part31 국내 기준에서 규정되어 있다. 고속 철도차량 기밀시험은 UIC 660 및 779-11에서 객실내 압력 변화율 규정이 있으며 차량 기밀도가 규정되어 있다. 국내 규격에서는 풍속에 대한 규정은 매우 미비하며, 태양광 복사 시험 및 강설 시험 규격은 존재하지 않는다. 철저한 기후환경 시험을 위하여 국내 철도 완성차 관련 기술기준 및 시험 규격을 국제수준으로 향상시킬 필요가 있는 것으로 판단된다.

• KIEAE Journal
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• 제14권6호
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• pp.99-104
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• 2014

Recently supply of low energy house is increasing which can enhance energy efficiency and indoor environment comfort. Low energy house have to secure air tightness as well as thermal performance so house become high airtightness and inevitably need heat recovery ventilator to enhance indoor air quality. However, most of current ventilation systems are one-click, controlling the entire space so it causes increasing of heating load and fan power which makes it hard to save energy. Thus, Individual Control system is required which can achieve both enhancing indoor air quality and decreasing heating load and electric fan power. Thereby, in this study, we analyzed the correlation between ventilation and fan power through mock-up experiment and measured ventilation load under individual control system. As a result, under the condition of $24^{\circ}C$ of indoor temperature for 6 month(November to April) in Daejeon, ventilation load by fan speed was $10.9{\sim}19.6kWh/m^2{\cdot}a$ when operated 24 hours and $7.6{\sim}13.7kWh/m^2{\cdot}a$ when operated 12 hours in night time. In addition, it is possible to reduce at most 60% of ventilation load under the individual control system; measured ventilation load was $7.4kWh/m^2{\cdot}a$ when operated 24 hours, and $5.5kWh/m^2{\cdot}$ when operated 12 hours in night time.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.751-756
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• 2009

In the perspective of saving energy in buildings, the high performance of insulation and air tightness for improving the heating and the cooling efficiency, has brought economically positive effects. However, these building energy saving technologies cause the lack of ventilation, which is the direct cause of increasing the indoor contaminants, and is also very harmful to the residents, because they spend over 90% of their time indoors. Therefore, the ventilation is important to keep the indoor environment clean and it can also save the energy consumption. In this study, a HEPA type nano ceramic filter is designed as a passive ventilation system to collect airborne particles and to supply fresh outdoor air. The double layer filter, which has $30{\mu}m$ in diameter at the conditions of 10wt% of concentration and 3kV/cm of the electric intensity, is produced by electrospinning. The filtration coating technology is confirmed in the solution with $SiO_2$ nano particles using polymer nano fibers. Also double layer filters are coated with $SiO_2$ nano particles and finally the porous construction materials are made by sintering in the electric furnace at $200{\sim}1400^{\circ}C$. The efficiency is measured 96.67% at the particle size of $0.31{\mu}m$, which is slightly lower than HEPA filter. However the efficiency is turned out to be sufficient.

• 한국전산유체공학회지
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• 제20권3호
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• pp.62-69
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• 2015

Pressure change inside cabin as well as in tunnel has been calculated to assess the passenger pressure comfort of high-speed train. $C-STA^{TM}$, a CFD program based on axi-symmetric Navier-Stokes equation and Roe's FDS has been used to simulate the pressure change in tunnel during a high-speed train passing through it. To present the relative motion between the train and the tunnel, a modified patched grid scheme based on the structured grid system has been employed. The simulation program has been validated by comparing the simulation results with field measurements. Extensive parametric study has been conducted for various train speed, tunnel cross-sectional area and tunnel length to the pressure change in cabin. KTX-Sancheon(KTX2) high-speed train has been chosen for simulation and the train speed have been varied from 200 km/h to 375 km/h. The tunnel length has been varied from 300 m to 7.5 km and tunnel area from $50m^2$ to $120m^2$. Total 504 simulations have been conducted varying the parameters. Based on the database produced from the parametric simulations, minimum tunnel cross-sectional area has been surveyed for various train speeds based on Korean regulation on pressure change in cabin.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.2198-2199
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• 2011

The sliding door and plug door are the main types of door system in the EMU(Electric Multiple Unit). The sliding door is widely used in Korea but has weak point in the noise problem. In the low operation speed, the noise coming from outer side of the EMU is not an important factor. As the speed is higher than before, noise is increased and make an issue. The main cause of noise is the imperfect air tightness in the EMU. The plug door system has advantages for the noise reduction characteristic in the high speed area. Actually the noise level is an important factor for the passenger comfort. In this paper, we will describe the characteristic of electric plug door and functions of sub component.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.97-100
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• 2007

Fuel Cell Stack performance, which is influenced by the maintenance of a constant internal environment, requires high levels of air tightness. Used for analysis, gasket for fuel cell is made of elastic rubber materials and placed over separator, and shape of deformation of a gasket affects the transformation separator and airtightness while fastening structure. Separator as made of steel sheet isn't broken under pressure but can affect gas and cool water flow by the plastic deformation process. Therefore， it is understood that assembly process is well developed in case distribution of stress and shape of deformation is shown uniformly. This study is conducted on the assumption that a fuel cell maintenance is advantageous in that conditions. In this paper, analyses of unit cell and partial model were performed and distribution of stress and shape of deformation of Gasket and separator were analyzed to evaluate the airtightness while fastening structure.