• Title/Summary/Keyword: 보조공기

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Analysis of Loss of HVAC for Nuclear Power Plant (원전의 공기조화설비(HVAC) 상실사고 분석방법)

  • Song, Dong-Soo
    • Journal of Energy Engineering
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    • v.23 no.1
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    • pp.90-94
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    • 2014
  • Environmental qualification (EQ) for safety-related equipment is required to ensure that those equipment will perform their required function even under the harsh environment conditions arising from design basis accident in the nuclear power plant. As a part of EQ program, the room temperature analysis in case of a loss of Heating, Ventilation, and Air Conditioning(HVAC) system was carried out to ensure the operability of the safety-related equipment of a nuclear power plant randomly chosen among the Korean nuclear power plants. In this paper, this analysis was performed in the conservative perspective using GOTHIC code. The room temperature analysis includes selecting the rooms in which the safety related equipment are located but not supported by safety related HVAC and determining the temperature of the selected rooms. Target rooms for the analysis consist of W229/W237 (Aux. feedwater pump room), W232 (Aux. feedwater tank room) and W230 (Equipment passageway). The results showed the temperature range from $43^{\circ}C$ to $83^{\circ}C$, in 72 hours after a loss of HVAC. Those values are far below of generic EQ temperature($171^{\circ}C$). Therefore, it is satisfied with EQ requirement of temperature limits on safety related equipment.

A Study on the Spontaneous Ignition of the Fuel Injected into a Hot Air Stream - Additional Report: Utilization of Diesel Oil and Emulsified Fuel- (高溫空氣流 에 噴射한 噴霧 의 自然燃燒 에 관한 硏究 -속보 : 경유 및 유화핵연료 사용-)

  • 방중철;태전간랑
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.9 no.5
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    • pp.627-637
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    • 1985
  • The combustion process and the performance of a diesel engine are seriously affected by the ignition delay period of the fuel used. Some methods for improving the combustion process in the engine cylinder are to well match the strength of air swirl with the space of sprays in the cylinder, to blend an ignition improver in the fuel, to inject a small amount of auxiliary fuel prior to main injection and so on. Recently, the improvement of fuel economy and the reduction of exhaust smoke and NO have been successfully achieved by supplying diesel engines with emulsified fuel. However, it is very difficult to know real combustion mechanism under such special conditions, because of many factors affecting on the combustion process in practical reciprocating engine. In the present paper, the combustion processes of diesel fuel and emulsion fuel were tried to improve and to observe by making contact with various lean pre-mixtures in the hot air stream duct. This hot air stream method has an advantage that the spontaneous combustion process can be observed under a simplified condition.

Effect on Flow Distortion of S-Duct by Boundary Layer Suction (경계층 흡입이 S-Duct의 유동 왜곡에 미치는 영향성 연구)

  • Baeg, Seungyong;Lee, Jihyeong;Cho, Jinsoo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.47 no.1
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    • pp.17-25
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    • 2019
  • An intake of Aircraft becomes S-shaped geometry due to spatial limitation or procuring survivability. But curvature of the S-shaped geometry makes secondary flow or flow separation which is the cause of non-uniform pressure distribution. In this study, boundary layer suction is applied to RAE M 2129 S-Duct by attaching sub duct. Design variable is suction location and angle. A mass flow rate drawn out by suction at the sub duct outlet is constant over every model. A grid dependency test was conducted to verify validity of computation. The comparison among the CFD (Computation Fluid Dynamics), ARA experimental result, and ARA computation result of non-dimensional pressure distribution on the Port side and Starboard Side confirmed the validity of CFD. In this study, Distortion Coefficient was used for evaluating aerodynamic performance of S-Duct. The analysis, which was about flow separation, vortex, mass flow rate distribution, and pressure distribution were also investigated. Maximum 26.14% reduction in Distortion Coefficient was verified.

Production of air purification verification system using moss (이끼를 활용한 공기정화 검증 시스템 제작)

  • Ahn, Dohyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.587-591
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    • 2019
  • Fine dust aerated in the atomsphere penetrates our lungs and blood lines through respiratory. Recent fine dust problems in Korea leads to development of various air purifiers. The researchers used this to study systems that could replace chemical filters. In order to compare the effect of the reduction of moss and conventional chemical filter(Hepa), a 1 cubic meter cube was prepared and the amount of the concentration of fine dust reduction was compared under controlled environment. Under the high concentration of fine dust, a test was done to figure out the reduction rate of the fine dust concentration by using air purification system with moss, hepa, and no filter. The air purification system(moss, hepa, and no filter) were operated 90 times in total, 30 times each. The test explains that the reduction of the fine dust amount and the rate of fine dust concentration. The results illustrate that the reduction of the amount fine dust was 138.93 after using air purification system with moss filter. In contrast, the usage of air purification system with hepa filter reduced the amount of fine dust to 76.57. And the air purification with no filter shows that the slight reduction of fine dust amount at 0.10. In the rate of fine dust concentration, moss filter was significantly higher than that of hepa, no filter (0.2379, 0.1298 and 0.0063 each). The results have confirmed that moss is effective in reducing fine dust concentration, and it is expected that with further improvement it can be used as a means to replace or supplement existing chemical filters in air purifier.

CERVICOFACIAL NECROTIZING FASCIITIS;CASE REPORT (경안면 괴사성 근막염;증례보고)

  • Park, Kwan-Soo;Jeong, Ki-Hoon;Kim, Hyo-Eon;Jeong, Jeong-Kwon;Yoon, Kyu-Ho;Jeon, In-Seong
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.23 no.1
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    • pp.77-81
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    • 2001
  • Necrotizing fasciitis is defined as infectious disease showing extensive necrosis of the superficial fascia with widespread involvement of the surrounding tissues and concurrent systemic toxicity. It is found commonly in the extremities, the trunk and the perineum, but shows extremely rare occurrence in the well vascularized area such as head and neck area. Occurred in the head and neck area, it is called "cervicofacial necrotizing fasciitis" (CFNF). It is a fatal disease which carries a mortality rate up to 60%. Early diagnosis, aggressive surgical debridement of necrotic tissues and massive antibiotics therapy are essential for achieving a favorable outcome. We present a case of cervicofacial necrotizing fasciitis in 35-year-old male patient with literature review.

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A Case Study on Blasting Demolition Method of Structure (구조물 발파해체 공법 시공사례 연구)

  • 한동훈;안명석;공병승;이윤재;류창하
    • Explosives and Blasting
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    • v.21 no.3
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    • pp.49-60
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    • 2003
  • Nowadays it is tendency to make a remodelling or demolition of old structures with the rapid development of blasting technique. In this treatise it is arranged of improvement procedure of blasting demolition method in korea which was begun since August 1991. Recently, the blasting demolition method has much merits with 60-70% reduction effect of construction period than mechanical demolition method. and so that it has much economical points specially over than 5 storied high buildings. In order to maximalize economical effects of the blasting demolition method, environment safety and recycling, it must be needed. at first to develop the estimating programs against vibration, noise, flying stones, and dust. Also it is required to take a responsibility for using recycling materials after blasting demolition of old structures, and to be invested to advance the blasting demolition techniques.

A Study on the In-Vitro Test of Thrombogenesis in Centrifugal Biopump (원심성 바이오 펌프를 이용한 혈전 생성의 생체 외 검사에 관한 연구)

  • Na, Myung-Hoon;Kim, Won-Gon;Kim, Joo-Hyun;Kim, Mee-Hyung;Yu, Jae-Hyeon;Lim, Seung-Pyung;Lee, Young
    • Journal of Chest Surgery
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    • v.32 no.10
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    • pp.863-873
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    • 1999
  • 배경: 혈전 생성은 심혈관계 삽입물이나 순환 보조장치의 발전에 있어서 중요한 문제이므로 이러한 장치들의 혈전성에 대한 평가는 필수적이다. 따라서 이러한 장치들의 혈전성 연구를 시행하기 위한 효과적인 생체 외 실험 방식이 개발되어 원심성 순환 펌프의 발전에 큰 도움이 되고 있으며, 최근 엄밀하게 혈액과 공기의 접촉을 차단하는 방식이 믿을 수 있는 생체 외 실험 방식으로 강조되고 있다. 본 논문에서는 모의 순환 회로를 이용하여 기존에 행해진 연구 방법 상의 공기 접촉에 따른 핼액 응고 기전의 활성화 여부를 알아보기 위하여 공기 접촉 여부에 따른 혈액 인자의 변화를 관찰하여 확인하고, 또한 회로 내에서 생성된 혈전을 생체 내에서 형성된 혈전과 비교 분석하여 이 모의 순환 회로를 이용한 생체 외 검사가 새로 고안된 심혈관계 장치들의 혈전성을 평가하는데 있어서 동물실험을 대신할 수 있다는 기존의 주장을 검증하고자 하였다. 연구재료 및 방법: 바이오펌프를 이용한 같은 모의 순환 회로 한 쌍을 준비하고 동일 개체에서 얻은 헤파린을 첨가한(1u/$m\ell$) 신선한 혈액을 공기와 접촉시키지 않도록 한 A-회로와 공기와 접촉시킨 B-회로에 충전시켜 실험을 동시에 진행하여 결과를 얻었으며 총 12번 시행하였다. 회로에 충전한 혈액의 activated clotting time(ACT)은 정상의 3~5배였으며 ACT가 정상 범위의 1.5배가되면 실험을 끝냈고, Hematocrit(HCT), 혈소판, 동맥혈가스분석(ABGA), factor Ⅷ, factor \ulcorner, 섬유소원, thromboxane B2(TXB2), free hemoglobin(fHb) 등을 측정하였다. 실험이 끝난 후 A-회로와 B-회로에서 얻은 각 검사를 평가하고 분석하였으며 생성된 혈전을 생체 내에서 생성된 혈전과 조직 검사로 비교하였다. 본 연구의 자료분석은 SPSS 통계 프로그램을 이용하였고 유의수준 0.05를 기준으로 유의도를 판단하였다. 결과: 정상 ACT는 186.9$\pm$20.5초(평균$\pm$표준편차)이었고, 헤파린을 넣은 초기 ACT는 982.2$\pm$165.5초이었으며, 실험시간은 보통 60분에서 180분 사이였다. HCT, fHb, 혈소판, TXB2, factor Ⅷ, factor \ulcorner, 섬유원소의 초기값은 35.5$\pm$3.2%, 12.4$\pm$6.5 mg/dL, 354$\pm$56($\times$103)/$\mu$L, 72.6$\pm$15.1 mg/dL, 29.3$\pm$1.2%, 137.9$\pm$42.1 mg/dL, 그리고 17.7$\pm$9.7%이었다. 공기 접촉에 따른 차이를 보았을 때 ACT(p=0.398), HCT(p=0.988), fHb(p=0.898), 혈소판 (p=0.904), TXB2(p=0.985), factor Ⅷ(p=0.872), factor \ulcorner(p=0.489), 섬유원소(p=0.973)으로 전 예에서 통계적 유의성이 없었다. 실험 후 양 군에서 생성된 혈전의 현미경 소견은 B-회로의 혈전에 여러 군데 공기 방울이 관찰되는 것 이외에 A-회로에서 생성된 혈전과 차이가 없었고, 생체에서 생성된 혈전과 비교했을 때 그 양상이 같았다. A-회로와 B-회로에서 생성된 혈전의 총 량은 8.4$\pm$3.7 mL와 9.4$\pm$3.1 mL로 통계상 유의성은 없었다. (p=0.624). 결론: 모의 순환 회로를 이용한 혈전성 평가를 위한 생체 외 실험에 있어서 공기와의 접촉 여부는 혈액 응고 기전의 활성화나 혈전 생성에 별다른 영향을 미치지 않는다. 모의 순환 회로에서 형성된 혈전과 문헌에 있는 인체 내에서 형성된 혈전을 비교한 결과 그 형태가 일치하므로 이 모의 순환회로를 이용한 실험이 동물실험을 대신할 수 있다고 판단된다.

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The Study on Operability Improvement of the start motor for Auxiliary Power Unit of Rotorcraft (회전익 항공기 보조동력장치 시동모터 운용성 개선연구)

  • Lee, Gwang-Eun;Kang, Byoung-Soo;Na, Seong-Hyeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.774-780
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    • 2021
  • The auxiliary power unit (APU) of a rotorcraft starts the engine during operation/flying. The APU is composed of a gas turbine engine type. The starting principle of the component is that the electric start motor generates the power required for starting by rotating the shaft. In this study, quality improvement was performed by applying an over-running clutch (ORC) between the APU and the starter motor to secure the operability of the starter motor of the APU mounted on the rotorcraft. The starter motor has the main role of starting the APU, but during operation, it is rotated without load by the rotational force of the APU gear shaft, resulting in friction at the brush. This phenomenon causes abrasion of the brush of the starter motor. Consequently, when the APU operation time increases, the brush life decreases, and the operability of the APU is affected. In this study, an ORC that separates the interlocking between the start motor brush abrasion and the APU operation time was applied to improve the operability/durability of the APU starter motor. The effect was verified through a test, and the technical feasibility of the design change was analyzed.

Physical Characteristics of PECVD SiON thin film for OLED passivation (OLED passivation에 적응하기 위한 PECVD SiON 박막의 물리적 특성)

  • Yoon, Jae-Kyoung;Kwon, Oh-Kwan;Yoon, Won-Min;Shin, Hoon-Kyu;Phak, Chan-Eon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.292-292
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    • 2009
  • OLED(Organic Light Emitting Device)는 LCD(Liquid Crystal Display)의 뒤를 잇는 차세대 디스플레이의 선두주자로서 자체발광형이기 때문에 백라이트 등의 보조광원이 불필요하며, 구동전압이 낮고 넓은 시야각과 빠른 응답속도 등의 특징을 가지고 있다. 또한 플렉서블 기판을 사용할 수 있어 차세대 디스플레이인 플렉서블 디스플레이에 적합하다. 플렉서블한 디스플레이를 만들기 위해서 플라스틱 기판에 OLED 물질을 사용하여 기존에 무겁고, 깨지기 쉬우며, 변형이 불가능한 유리로 만든 소자 보다 더 가볍고 깨지지 않고 변형이 가능한 플렉서블 디스플레이를 제작 할 수 있다. 그러나 플라스틱 기판은 매우 큰 투습율을 가지고 있어 OLED소자에 적용시키면 공기 중의 수분이나 산소와 접촉이 많아져 쉽게 산화되어 소자의 효율 및 수명이 짧아진다. 또한 OLED에 사용되는 유기물도 산소나 수분에 의해 특성이 급격히 저하되기 때문에 산소 및 수분의 차단은 필수적이다. 이러한 단점을 최소화하기 위해서 PECVD(Plasma Enhanced Chemical Vapor Deposition)로 만든 SiON(Silicon Oxynitride) 박막을 차단막(Passivation layer)으로 사용하였다. PECVD를 이용하여 SiON 박막을 증착시킬 때 RF Power, 공정압력, Distance의 변화에 따른 박막의 결정화도, 수분투습도, 광투과도 등의 특성을 FT-IR(Fourier Transform Infrared Spectroscopy), Ellipsometer, UV-visible Spectrophotometer, MOCON를 이용하여 SiON 박막의 특성을 고찰하였다.

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Characteristics of the Gasoline Spray near Impinging Wall in Suction Flow (흡입유동 중 충돌벽면 근처에서 가솔린 분무특성)

  • Kim, Won-Tae;Kang, Shin-Jae;Rho, Byung-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.10
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    • pp.1285-1293
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    • 2000
  • In port fuel injection system of SI engines, injected fuel is impinged onto the surface of intake valves and port-wall, and then formed the wall flow under the cold start operation. Wall flows entrained into the cylinder result in the unsteady and nonuniform mixture formation. Therefore, the spray impingement to the wall is considered as having negative influences such as lowering combustion efficiency and causing unburned hydrocarbon emissions. This study investigates the spray characteristics of the wall impinging air-assist spray in suction air flow. A PDPA was used to analyze the flow characteristics under the different conditions such as impingement angle and supplied air. Experimental data concerning the impinging sprays has been obtained in the vicinity of the wall. Measured droplets divided into the pre-impinging droplets which denote as the positive normal velocities and post-impinging droplets that describe as the negative normal velocities for the suction flow. Their velocities, size distributions and SMD are comparatively analyzed before and after the impingement.