• 제목/요약/키워드: Air-tightness Performance

검색결과 46건 처리시간 0.019초

5 kW급 건물용 연료전지 시스템 연료승압 블로워 안전 성능 평가에 관한 연구 (A Study on Safety Performance Evaluation of NG Blower for 5 kW Class Stationary Fuel Cell Systems)

  • 백재훈;이은경;이정운;이승국;문종삼;김규형;박한우;김동철;이진희
    • 한국수소및신에너지학회논문집
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    • 제28권6호
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    • pp.675-682
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    • 2017
  • New government, the market for stationary fuel cell systems in domestic is expected to expand in line with the policy for expanding new and renewable energy. In order to promote and expand the domestic market for stationary fuel cell systems, it is required to do research and develop for cost reduction and efficiency improvement technologies through the localization of BOP. In this study, the safety performance including the power consumption, flow rate, noise and air-tightness of the domestic fuel booster blower and the foreign fuel booster blower was evaluated and the performance improvement of the domestic blower was confirmed. As a result of the power consumption measurement and the flow rate according to the back pressure of the A company 2nd prototype and B company, the values were 73 W, 27 LPM, and 55 W, 25 LPM. These results are attributed to the improvement of performance through design changes such as CAM angle and diaphragm material.

철도차량 기후환경시험을 위한 국제 규격(UIC, EN, IEC) 및 국내 규격(시험방법) 분석 및 고찰 (Analysis and Investigation of International(UIC, EN, IEC) and Domestic Standards(Test Methods) for Climatic Wind Tunnel Test of Rolling Stock)

  • 장용준;정종덕;이재천
    • 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.

수상함 격실기밀시험 결과의 신뢰성 확보를 위한 압력 보정 시스템 개발 (Development of Pressure Correction System for Surface Vessel to Ensure Reliability of Compartment Test Result)

  • 민일홍;김준우;손기중
    • 한국산학기술학회논문지
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    • 제22권1호
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    • pp.409-414
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    • 2021
  • 수상함이 전투 환경에서 우수한 임무수행능력과 생존성을 구현하기 위해서는 구획을 차단하는 수밀/기밀 성능이 중요하다. 위와 같은 요구사항을 충족을 위해 함정 건조 후 시운전에서 구조요소(격실 및 탱크)에 대한 밀폐성과 특정부위에 대한 강도의 적합성을 검사하며, 특히 수선에 인접한 격실들의 격실기밀시험(Air test)을 수행한다. 격실기밀시험은 대상 격실에 공기를 주입하여 시운전 평가서 상의 요구압력까지 압을 적용하고, 일정 시간동안 압력강하 값을 확인하여 해당 구역의 요구조건 충족여부를 판단한다. 검사 기준은 10분 동안 감소된 압력이 시운전 평가서의 압력강하 허용치 이내이어야 한다. 하지만 외기온도의 영향이 큰 여름철에 격실기밀시험 진행 간 유입되는 열이 내부 공기의 온도를 상승시키고, 이로 인해 공기가 팽창하여 격실 내 압력이 증가하는 현상이 식별되었다. 이러한 현상은 격실기밀시험에서 최종 압력강하 값을 정확히 판단할 수 없게 하고 평가결과에 대한 신뢰성을 결여시킬 수 있다. 본 연구를 통해 격실 내 온도변화 영향을 보정하기 위한 시스템을 고안하였다. 개발된 시스템은 격실 내 온도변화에 의한 압력 변화량을 계산하여 보정값을 출력한다. 이상기체 방정식을 통해 압력변화량을 계산하며, 격실기밀시험 간 온도유지 및 증가/감소를 반영할 수 있도록 개발되었다. 계산된 압력 보정값을 NIST REFPROP의 데이터 베이스와 비교하였을 때, 최소 0.126 %에서 최대 0.253 %의 차이를 보였다.

겨울철 공동주택에서 붙박이장 내 보조난방장치를 활용한 결로 저감 효과 평가 (Assessment of Utilization of Auxiliary Heating Device for Prevention of Condensation in Built-in Furniture in Winter)

  • 이현화;임재한;송승영
    • 대한건축학회논문집:구조계
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    • 제33권12호
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    • pp.99-106
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    • 2017
  • Recently, the condensation and mold problems of apartment buildings has been growing due to high insulation and high air-tightness performance for energy saving. Most of all, occupants in residential buildings has suffered from property damages due to the condensation and mold of built-in furniture. Condensation at built-in furniture were generally found in winter at the of furniture's back panels, adjacent surfaces of wall, floor and ceiling. The aim of paper is to analyze the characteristics of adjacent area around built-in furniture's condensation problem and the thermal environment around the built-in furniture in winter through the field measurements at apartment buildings. In this research, the thermal conditions and surface temperature around the built-in furniture were measured during winter season. In this research, we analyzed thermal conditions for built-in furniture which were applied and not applied auxiliary heating device. In results, it is important to consider increasing surface temperature for using heater and decreasing absolute humidity due to the occupants' behavior around built-in furniture for preventing condensation.

Deformation Characteristics and Sealing Performance of Metallic O-rings for a Reactor Pressure Vessel

  • Shen, Mingxue;Peng, Xudong;Xie, Linjun;Meng, Xiangkai;Li, Xinggen
    • Nuclear Engineering and Technology
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    • 제48권2호
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    • pp.533-544
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    • 2016
  • This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap) have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제29권6호
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.