• Title, Summary, Keyword: 압력용기

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Development of Pressure Drop Model for the Compartment in Reactor Containment (격납용기내 구분방사이의 압력 강하 계산모델 개발)

  • Park, Cheol;Song, In-ho;Lee, Un-Chul
    • Nuclear Engineering and Technology
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    • v.18 no.3
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    • pp.183-193
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    • 1986
  • Full scale HDR containment experiment series pointed out that the previous containment analysis models have a number of shortcomings. One of them is on the calculational model of short term (0~2sec) pressure difference. The pressure differences between subcompartments are dependent on the flow rate, fluid density, head loss coefficient, and flow area ratio. It, however, is not known that any of them is largely attributed to the disagreement of pressure difference between the measured and the calculated values. In this study, the head loss coefficients are expressed with another form to improve the analytic model. The pressure and the pressure difference are evaluated by using COMPARE code with new correlation, and the results show better agreements with experimental values for V.42 test, but overestimate the measured values for V, 43 and underestimate for V.44.

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FEM Analysis on the Strength Safety of a LPG Cylinder (LPG용기의 강도 안전성에 관한 유한요소해석)

  • Kim, Chung-Kyun;Jeong, Nam-In
    • Journal of the Korean Institute of Gas
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    • v.11 no.2
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    • pp.55-59
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    • 2007
  • This paper presents the strength safety of a LPG cylinder, which is fabricated by a steel sheet forming and a welding technology. The strength safety of a cylinder is guaranteed by analyzing a stress distribution of a LPG cylinder structure using a finite element method. The FEM computed results indicate that the hydraulic test gas pressure of $31kg/cm^2$ generates a concentrated local stress near the upper round end plate, which exceeds the yield strength of a LPG cylinder. Thus, the current hydraulic test pressure may be rechecked and revised because this pressure increases the fatigue failure and decreases the lift of the pressure vessel. The normal operation and sealing gas pressures such as $9kg/cm^2\;and\;18.6kg/cm^2$ are relatively safe for a steel LPG cylinder.

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A Study on Analysis Method to Evaluate Influence of Damage on Composite Layer in Type3 Composite Cylinder (Type3 복합재료 압력용기의 복합재층 손상에 따른 영향성 평가를 위한 해석기법에 관한 연구)

  • Lee, Kyo-Min;Park, Ji-Sang;Lee, Hak-Gu;Kim, Yeong-Seop
    • Composites Research
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    • v.23 no.6
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    • pp.7-13
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    • 2010
  • Type3 cylinder is a composite pressure vessel fully over-wrapped with carbon/epoxy composite layers over an aluminum liner, which is the most ideal and safe high pressure gas container for CNG vehicles due to the lightweight and the leakage-before-burst characteristics. During service in CNG vehicle, if a fiber cut damage occurs in outer composite layers, it can degrade structural performance, reducing cycling life from the original design life. In this study, finite element modeling and analysis technique for the composite cylinder with fiber-cut crack damage is presented. Because FE analysis of type3 cylinder is path dependant due to plastic deformation of aluminum liner in autofrettage process, method to introduce a crack into FE model affect analysis result. A crack should be introduced after autofrettage in analysis step considering real circumstances where crack occurs during usage in service. For realistic simulation of this situation, FE modeling and analysis technique introducing a crack in the middle of analysis step is presented and the results are compared with usual FE analysis which has initial crack in the model from the beginning of analysis. Proposed analysis technique can be used effectively in the evaluation of influence of damage on composite layers of type3 cylinder and establish inspection criteria of composite cylinder in service.

Tensile and Fatigue Behavior of ASS304 for Cold Stretching Pressure Vessels at Cryogenic Temperature (Cold Stretching 압력용기용 ASS304 소재의 극저온 인장 및 피로거동)

  • Choi, Hoon Seok;Kim, Jae Hoon;Na, Seong Hyun;Lee, Youn Hyung;Kim, Sung Hun;Kim, Young Kyun;Kim, Ki Dong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.5
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    • pp.429-435
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    • 2016
  • Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress ${\sigma}_k$. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM).

LPG 압력 조정기용 다이아프램의 특성에 관한 연구

  • Kim, Hong;Jung, Ki-Chang;Cho, Ki-Sung;Lee, Young-Chul
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • pp.109-113
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    • 1998
  • 압력조정기란 저장탱크와 용기로 부터 연소기에 공급되는 가스압력을 연소기의 압력에 맞게 조절하여 정상연소가 되도록 돕는 장치로써, 용기 및 저장탱크내의 압력변화에 대응하여 공급압력을 일정하게 유지하고, 가스의 조성, 온도, 소비량, 소비시간, 잔류가스량 등의 변화에 따라 감압작용과 정압작용을 동시에 하는 장치이다. LPG용 압력조정기는 일반가정용이나 업소에서 주로 사용하는 조정기로써 용량 4kg/h부터 집단공급용인 수백 키로까지의 제품이 있으며 일반적으로 감압작용, 정압작용, 폐쇄작용을 한다. (중략)

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Defects Classification with UT Signals in Pressure Vessel Weld by Fuzzy Theory (퍼지이론을 이용한 압력용기 용접부 초음파 결함 특성 분류)

  • Sim, C.M.;Choi, H.L.;Baik, H.K.
    • Journal of the Korean Society for Nondestructive Testing
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    • v.17 no.1
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    • pp.11-22
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    • 1997
  • It is very essential to get the accurate classification of defects in primary pressure vessel and piping welds for the safety of nuclear power plant. Ultrasonic testing has been widely applied to inspect primary pressure vessel and piping welds of nuclear power plants during PSI / ISI. Classification of flaws in weldments from their ultrasonic scattering signals is very important in quantitative nondestructive evaluation. This problem is ideally suited to a modern ultrasonic Pattern recognition technique. Here, a brief discussion on systematic approach to this methodology is presented including ultrasonic feature extraction, feature selection and classification. A stronger emphasis is placed on Fuzzy-UTSCS (UT signal classification system) as efficient classifiers for many practical classification problems. As an example Fuzzy-UTSCS is applied to classify flaws in ferrite pressure vessel weldments into two types such as linear and volumetric. It is shown that Fuzzy-UTSCS is able to exhibit higher performance than other classifiers in the defect classification.

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추진기관 연소관의 결함 영향 분석에 관한 연구

  • 김성은;문순일;오광환;김정배;이원기
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • pp.171-177
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    • 1995
  • 추진기관 연소관 제작시 발생하는 결함등에는 주로 표면결함의 형태의 것이 많은데 연소관 설계시 이러한 결함들의 영향을 고려하는 것이 구조물의 안정성에 있어 중요한 요소가 된다. 따라서 본 논문에서는 연소관에 발생할수 있는 결함들에 대한 파단하중 및 파단압력에 대한 탄성 및 탄소성해석을 통하여 파괴 매개변수인 J적분을 유한요소 프로그램인 ABAQUS를 이용하여 3차원 비선형해석을 수행하여 5가지의 균열모델을 사용하여 평판, 양단개방 압력용기(open tube) 및 양단막힘 압력용기 (closed tube)의 파단하중하에서의 J적분의 영향을 분석하였다. 평판 결함시편의 J적분으로부터 압력용기의 손상허용설계를 할 수 있는 방안을 조사 하였으며 추진기관 연소관에 적용하여 발생가능한 크기의 결함에 대한 안정성을 조사한결과 충분한 안정성을 확보하고 있음을 알수 있었다.

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An Experimental Study on Confined Steel Structure Blasting Demolition (폭약을 이용한 밀폐압력용기 해체에 관한 기초적 실험연구)

  • Lee, Ha-Young;Kim, Yong-Kyun;Yang, Kuk-Jung;Hur, Won-Ho;Kang, Dae-Woo
    • Explosives and Blasting
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    • v.30 no.2
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    • pp.43-51
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    • 2012
  • The Demolition blasting has been applied for buildings and structures so far. In this study, however, a confined vessel blasting filled with water has been focused. A small amount of explosives were placed in a sealed vessel with water, perfect elastic body, supposed as a relay agent in it, and the blasting aspect was observed. Blasting pressure was standardized by Abel's equation of state. In result, if there was a relay agent in it, the pressure vessel was torn apart with smaller power than its tensile strength. If there was not, it needed 7.1~8.5 times as much power as the previous one, and the blasting pressure had not also affected the demolition and it had gone or vanished until it reached a certain point, In terms of pressure vessel made by steel, the elastic-plastic failure was took a place, and the first yield point happened along the welded area as a form of heating plastic failure we thought.

Transient Analysis of Pressure Behavior of Cryogenics in Closed Vessel (극저온 저장용기의 내부압력 거동에 대한 비정상해석)

  • 강권호;김길정;박영무
    • Journal of Energy Engineering
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    • v.5 no.1
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    • pp.19-27
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    • 1996
  • Self-pressurization of cylindrical container of cryogen is numerically analyzed. The container is axi-symmetric and heated from side wall with constant heat flux. Natural convection by external heat flux is studied numerically using finite difference method. Oxygen, nytrogen and hydrogen are working fluids in this paper. Liquid is considered incompressible fluid and vapor is assumed to behave as gas meeting with virial equation of gas. The Second virial coefficients of gas are obtained from Lennard-jones model. The important variables which have effects on self-pressurization are external heat flux, heat capacity of wall and initial ullage in container. The most important variable of them is external heat flux. The pressure rise calculated from the virial gas model is slightly different from that calculated using Ideal gas model for oxygen.

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Neuron Irradiation Effect and Intefrity of Nuclear Reactor Presure Vessel (원자로 압력용기에서의 중성자 조사효과 및 건전성)

  • 홍준화
    • Journal of the KSME
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    • v.33 no.5
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    • pp.393-404
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    • 1993
  • 원자로 압력용기의 수명 및 건전성을 결정짓는 중성자 조사취화현상에 대해 손상과정, 기구, 영 향인자, 예측 및 평가방법을 소개하였다. 용기재료의 현상, 특성과 설계, 제조, 운전시의 건전성 확보를 위한 활동 및 방법도 함께 살펴보았다. 설계시는 물론 수명기간 동안 건전성을 유지하 면서 운전하고 나아가 수명연장 운전을 위해서는 용기의 상태(파괴인성치, 결함, 작용응력)를 정확히 진단, 예측, 평가해야 하고, 이들이 건전성에 미치는 영향평가와 건전성 평가방법을 통한 수명예측 기술의 확보가 매우 중요하다. 특히, 고리 1호기가 가동된지 15년이 되어 계속적인 감 시가 요구되고 수명연장 타당성 연구를 추진중에 있으며, 영광 3, 4호기를 시작으로 앞으로 건 설되는 원자로가 국내에서 제작 . 설치되고, 설계 및 소재의 국산화율을 높이고자 하는 우리나 라에서는 더욱 그러하다. 미소시험법 및 시편재활용 기술개발을 통한 시험자료의 확충과 국내 원자로에 대한 데이터베이스 구축 및 각 발전소 특유의 경향곡선 확립 . 적용이 필요하며, 조사 손상 기구 및 모델링 관련연구가 계속되어야 한다. 조사효과에 대한 기초 및 응용연구는 1994년 한국원자력연구소의 다목적연구용원자로(MRR ; multipurpose research reactor) 가동과 더불어 더욱 활발해질 것이다.

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