• Title, Summary, Keyword: 입구 부

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이안제 배치에 따른 항내로의 파랑전파특성에 관한 수치해석

  • Kim, Tak-Gyeom;Yu, Ha-Sang;Lee, Gwang-Ho
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • pp.73-75
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    • 2018
  • 항만시설 및 배후지를 파랑으로부터 방호하는 기능을 가지는 외곽시설 중 항내 정온을 유지하여 하역효율을 높이고, 항내 항행 및 정박 중인 선박의 안전을 확보하고, 항내시설을 보전하기 위하여 설치하는 것으로는 방파제가 있으며, 배치형태로는 항의 외곽에 설치되는 경우와 연안으로 이격되어 설치되는 경우가 있다. 연안으로 이격되어 설치되는 이안제는 필연적으로 방파제 양단으로 회절파랑이 발생하게 되며 이안제 좌 우측으로 각각 분기되어 진행하는 파랑은 회절에 의해 방파제 배후 안쪽으로 휘어져 위상간 간섭을 일으키며 중첩되면서 전파된다. 지형적인 여건으로 진행방향이 같아지게 되고 항 입구부로 향한다면 파랑의 에너지 중첩에 의한 영향이 항내로 나타날 수 있다. 본 연구에서는 항 입구부에 이안제가 설치되는 경우, 이안제 길이에 따라 발생하는 좌 우측 회절 파랑의 위상차가 항내 파고에 미치는 영향을 수치실험을 통해 검토하였다. 이로부터 항내에서의 파고는 이안제의 길이에 따른 좌 우측 회절 파랑의 위상차에 의한 중첩의 영향으로 증폭 혹은 상쇄되어 나타남을 확인하였다.

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Effect of Inlet Humidity Condition at Cathode Side on Performance of a Polymer Exchange Membrane Fuel Cell (캐소드극 입구 가습 조건이 고분자 전해질 연료전지의 성능에 미치는 영향)

  • Moon, Cheor-Eon;Lee, Seo-Hee;Ko, Dong-Soo;Yang, Jang-Sik;Choi, Gyung-Min;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • pp.3423-3428
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    • 2007
  • This paper shows that inlet humidity condition at cathode side is one of dominant parameters affecting the performance of PEMFC. To investigate effects of inlet humidity condition, the performance measurements were conducted for a single PEMFC with two operating variables : cathode relative humidity and dry condition in anode dry. The fuel cell employed for the experiments is a unit PEMFC with a 25$Cm^2$, Nafion$^(R)$112 membrane. As a result of this study, the cell performance is getting higher by increasing inlet humidity condition at cathode side. The cell performance is different from each operating temperature an it has maximum30% higher than dry condition at 60$^{\circ}C$ operating temperature with 80% relative humidity.

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An Analysis of Flashing Jet Behavior of Pressurized Water (물제트의 노즐 입구온도변화에 따른 증발특성 해석)

  • KIM, BOOSANG;KIM, HAKDEOK;LIM, HEECHANG;SONG, JUHUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.30 no.6
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    • pp.585-592
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    • 2019
  • In this study, a flashing boiling phenomenon of pressurized water jet was numerically studied and validated against an experimental data in the literatures. The volume of fluid (VOF) technique was used to consider two-phase behavior of water, while the homogeneous relaxation model (HRM) model was used to provide the velocity of phase change. During the flashing boiling through a nozzle, a mach disk was observed near nozzle exit because of pressure drop resulting from two-phase under-expansion. The flashing jet structure, local distributions of temperature/vapor volume fraction/velocity, and position of the mach disk were examined as nozzle inlet temperature changed.

탐방 - "공무원연금관리공단 광주사무소"

  • Lee, Mi-Suk
    • 방재와보험
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    • pp.72-74
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    • 2005
  • 입구 도로 양 편에 늘어선 아름드리 벚꽃나무들이 운치 있는 분위기를 자아내고 있는 "공무원연금관리공단 광주사모소"는 화재 등의 재해로부터 인명과 재산을 보호함은 물론 이곳을 방문한 광주시민들의 안전을 목적으로 건물 내에서 일어나는 사소한 일까지도 세심하게 관리하고 있다.

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Transtibial Double Bundle PCL Reconstruction using TransFix Tibial Fixation - Technical Note - (TransFix 경골부 고정을 이용한 경 경골 두 다발 후방십자인대 재건술 - 수술 술기 -)

  • Lee, Yong-Seuk;Jung, Young-Bok;Ahn, Jin-Hwan;Kang, Bun-Jung;Shin, Yun-Chang;Kong, Chae-Gwan
    • Journal of the Korean Arthroscopy Society
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    • v.10 no.2
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    • pp.203-208
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    • 2006
  • Purpose: Previous transtibial double bundle posterior cruciate ligament (PCL) reconstruction methods have several problems in graft length and tibial fixation. We introduce new surgical method that is less restrictive by graft length and is more stable with single tibial fixation. Operative technique: After diagnostic arthroscopy, we prepare the graft, ream the tibial tunnel and perform the procedure for TransFix tibial fixation. Femoral 2 tunnel is made and graft is passed via anteromedial (AM) portal. Tibial fixation is done and femoral 2 graft is fixed sequentially at each knee position. Conclusion: TtransFix tibial single fixation method in double bundle PCL reconstruction provides more stable fixation, more free graft selection and prevents graft damage by passing the graft via AM portal.

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Scattering of Obliquely Incident Waves by a Semi-infinite Breakwater or a Breakwater Gap of Partial Reflection (부분 반사 반무한 방파제 또는 방파제 개구부에 사각으로 입사하는 파의 산란)

  • Kim, Han-Na;Suh, Kyung-Duck
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.4
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    • pp.334-344
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    • 2009
  • In the present paper, analytic solutions are derived for scattering of obliquely incident waves by a semi-infinite breakwater or a breakwater gap of partial reflection. In order to examine the appropriateness of the derived solutions, they are compared with the solutions derived by McIver in 1999 and Bowen and McIver in 2002 for a semi-infinite breakwater and a breakwater gap, respectively, in the case of perfect reflection. The derived analytic solutions are used to investigate the effect of reflection coefficient of the breakwater and wave incident angle upon the tranquility at harbor entrance. The tranquility is deteriorated by the reflected waves as the reflection coefficient increases and as the waves are incident more obliquely.

An Experimental Study on the Characteristics of the Vitiated Air Heater in the Ramjet Engine Ground-Testing (램제트 엔진의 지상시험용 Vitiated Air Heater의 특성에 관한 실험적 연구)

  • 윤현진;손창현;이충원
    • Journal of the Korean Society of Propulsion Engineers
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    • v.3 no.4
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    • pp.51-57
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    • 1999
  • Temperature and velocity controlling of air at inlet position of Ramjet combustor is important under Ramjet engine grounding-test condition since temperature of inlet air increases due to compression process by supersonic flow at inlet position of Ramjet combustor. In this study, Vitiated Air Heater methodology was used to control temperature of air that is inducted into Ramjet combustor. Temperature and velocity of air at Vitiated air heater exit, which is inducted into Ramjet combustor, were measured to evaluate Vitiated air heater system developed in this study. It is shown that temperature and velocity of inducted air can be well controlled using Vitiated air heater system developed in this study, and we could make a Vitiated Air which is almost same with real air.

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