• Title/Summary/Keyword: 배관 모델링

Search Result 63, Processing Time 0.025 seconds

IRWST 배관내의 열수력적 현상 모델링

  • 김상녕;김융석;고종현
    • Proceedings of the Korean Nuclear Society Conference
    • /
    • 1998.05a
    • /
    • pp.596-602
    • /
    • 1998
  • 한국의 차세대 원자로 (Korean Next Generation Reactor; KNGR)에 처음 적용되는 격납건물내에 설치된 재장전수조 (In-Containment Refueling Water Storage Tank; IRWST)는 기존 재장전수조의 기능외에 주입모드에서 재순환 모드를 전환생략, 일차계통으로 방출된 고온, 고압 냉각수의 응축 및 냉각 격납용기 방사능 오염방지, 원자로 동공층수 등 여러 가지 추가 기능을 가진 한층 진보된 설계개념이다. 발전소 천이사고 시 발생하는 Pipe Clearing, 응축진동 현상(Condensation Oscillations), Chugging 등의 열수력 현상들이 방출증기의 유동 및 가속도와 관련해 항력과 응력, 압력진동 등을 일으켜 IRWST 구조물에 영향을 미칠 수 있기 때문에 IRWST를 처음으로 시도하는 우리 나라로서는 이와 관련된 제반현상에 대한 심도 깊은 연구가 요구된다. 따라서 본 연구에서는 원자력 발전소 과도로 인한 가압기 안전밸브(Pressurizer Safety Valve) 또는 안전감압밸브(Safety Depressurization Valve) 작동시 IRWST로 방출되는 유체로 야기되는 하중 예측 모델을 기존의 BWR의 응축수조(suppression Pool)에서 일어나는 각종 현상을 토대로 이론적으로 체계적으로 유도하여 이를 비교, 분석하였다.

  • PDF

Pipe Offset Routing Program By Using 3D CAD For Shipbuilding (조선전용 3차원 CAD 시스템을 이용한 Pipe Offset Routing 프로그램 개발)

  • Kim, Sung-Min;Sheen, Dong-Mok
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.45 no.4
    • /
    • pp.432-440
    • /
    • 2008
  • Korean shipbuilders are starting to use three dimensional solid CAD systems to enhance their competitiveness in design and production. Despite many merits, three dimensional CAD systems reveal some problems in pipe-line modeling. Pipe-line modeling is heavily dependent on point data in routing. However, since the models built by sweeping or skinning operations do not have data about points and lines on the surfaces, the point data for routing are currently manually calculated by considering the diameters of the pipes and alignment conditions with other pipes. This process is inefficient and prone to errors. In order to enhance the pipe modeling, this paper presents an Offset Routing Program for a three dimensional CAD system, which aids designers to easily define the start points and to generate the pipe routings using reference objects.

A study on Water Quality Changes in Distribution System (Factor analysis of deterioration of water quality & Modelling of free chlorine) (상수도 배관망에서의 수질변화에 관한 연구 (수질악화의 영향인자 분석과 잔류염소 모델링))

  • Lee, Hyun Dong;Chung, Won Sik;Moon, Sook Mi
    • Journal of Korean Society of Water and Wastewater
    • /
    • v.11 no.3
    • /
    • pp.59-66
    • /
    • 1997
  • Although it produces well-treated water in water treatment plant, water quality at the tap can be changed depending on the state of pipes. It is because water quality deteriorates as plant water passes through pipeline networks. Therefore, the improvement of not only water treatment technology but also O & M of water pipelines is required to supply good water to consumers. The purpose of the study was to obtain the basic data of control technology for water quality in pipes through investigating water quality in distribution system. We selected 11 sampling sites and investigated water quality from plant to endpoint of distribution system. we also simulated decreasing tendency of free chlorine through pipeline network. As the result of water quality test, all parameters were below allowable levels, but some parameters had the possibility of being over levels. So there must be more work to set up proper countermeasure for violable parameters.

  • PDF

Seismic Evaluation for Strainer in the Primary Cooling System (일차 냉각계통 스트레이너에 대한 내진 건전성 평가)

  • 정철섭
    • Journal of the Computational Structural Engineering Institute of Korea
    • /
    • v.13 no.3
    • /
    • pp.295-304
    • /
    • 2000
  • To evaluate the structural integrity for the strainer under seismic loading the seismic analysis and design were performed for T-type strainer in accordance with ASME, Section Ⅲ, Class 3(ND). Since there are no specified design requirements for the strainer in ASME Code, the strainer body was analysed according to ND-3500, valve design. Flanged joints connected with PCS piping were designed according to ND-3658.3. And the criteria for the cover flange was governed by the Appendix XI. Both a frequency analysis and an equivalent static seismic analysis of the strainer were carried out using the finite element computer program, ANSYS. The frequency analysis results show the fundamental natural frequency is greater than 33Hz, thus justifying the use of the equivalent static analysis through which membrane and bending stresses are obtained in the critical points near the branch connection area. The results of the seismic evaluation fully satisfied with the structural acceptance criteria of the ASME Code. Accordingly the structural integrity on the strainer body and flanges were proved.

  • PDF

A Study About Critical Flow Characteristics and the Pipeline Network Modeling of a Pressure Regulator (I) - The Influence of a Pressure Ratio - (정압기의 임계유동 특성과 배관망해석 모델링에 관한 연구 (I) - 압력비 영향 -)

  • Shin Chang Hoon;Ha Jong Man;Lee Cheol Gu;Her Jae Young;Im Ji Hyun;Joo Won Gu
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.12 s.243
    • /
    • pp.1291-1298
    • /
    • 2005
  • Since the interior shape of a pressure regulator is complex and the change of fluid resistance at each operation condition is rapid and big, the pressure regulator can become the major factor that causes big loss in pipelines. So the suitable pressure regulator modeling by each operation condition is important to obtain reliable results especially in small scale pipeline network analysis. And in order to prevent the condensation and freezing problems, it is needed to confirm both whether temperature recovery is achieved after passing by the pressure regulator's narrow neck and how much amount of low temperature area that can cause condensate accumulation is distributed by various PCV models at every inlet-outlet pressure ratio. In this research, the numerical model resembling P company pressure regulator that is used widely for high pressure range in commercial, is adopted as the base model of CFD analysis to investigate pressure regulator's flow characteristics at each pressure ratio. Additionally it is also introduced to examine pressure regulator's critical flow characteristics and possibility of condensation or freezing at each pressure ratio. Furthermore, the comparison between the results of CFD analysis and the results of analytic solution obtained by compressible fluid-dynamics theory is attempted to validate the results of CFD modeling in this study and to estimate the accuracy of theoretical approach at each pressure ratio too.

A Study About Critical Flow Characteristics and the Pipeline Network Modeling of a Pressure Regulator (II) - The Influence of a Opening Ratio - (정압기의 임계유동 특성과 배관망해석 모델링에 관한 연구 (II) - 개도비 영향 -)

  • Shin Chang Hoon;Ha Jong Man;Lee Cheol Gu;Her Jae Young;Im Ji Hyun;Joo Won Gu
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.12 s.243
    • /
    • pp.1299-1306
    • /
    • 2005
  • The suitable pressure regulator modeling at each opening ratio and pressure ratio is very important to obtain reliable results, especially in small scale pipeline network analysis such as a pressure regulator system. And it is needed to confirm both whether temperature recovery is achieved after passing by the pressure regulator's narrow neck and how much amount of low temperature area that can cause condensate accumulation is distributed by various PCV models and driving conditions. In this research, the numerical model resembling P company pressure regulator that is used widely for high pressure range in commercial, is adopted as the base model of CFD analysis to investigate pressure regulator's flow characteristics at each pressure ratio and opening ratio. And it is also introduced to examine pressure regulator's critical flow characteristics and possibility of condensation or freezing at each pressure ratio and opening ratio. Additionally, the comparison between the results of CFD analysis and the results of analytic solution obtained by compressible fluid-dynamics theory is attempted to validate the results of CFD modeling in this study and to estimate the accuracy of theoretical approach at each pressure ratio and opening ratio too.

A study on the temperature distribution characteristics in the tube modules of a heat recovery steam generator ith the change of heat transfer modeling (배열회수 보일러 전열관군에서 열전달 모델링에 따른 온도 분포 특성 연구)

  • Ha, Ji Soo
    • Journal of Energy Engineering
    • /
    • v.24 no.2
    • /
    • pp.103-109
    • /
    • 2015
  • A heat recovery steam generator consists of inlet expansion duct and heat transfer tube bank modules. For the enhancement of heat transfer in the tube bank modules, the flow should be uniform before the 1st heat transfer tube bank module. The present study has been carried out to analyze the flow characteristics in the inlet expansion duct of a heat recovery steam generator by using numerical flow analysis. The aim of the present study is to establish the proper heat transfer mechanism in the heat transfer tube bank modules by the comparison of the heat transfer models, the case with the constant heat loss per unit volume and the case with heat loss by using inner and outer convective heat transfer coefficient of heat transfer tube. From the present research, it could be seen that the heat transfer mechanism with using inner and outer convective heat transfer coefficient derives more proper temperature distribution results and the acceptance criteria of the temperature distribution within ${\pm}10^{\circ}C$ before SCR is satisfied with using this heat transfer mechanism.

Experimental Research of Characteristic of Pool Boiling Heat Transfer of Saturated Liquid Nitrogen with Helical Coil Type Heat Exchanger (나선형 튜브 열교환 방식의 포화 상태 액체질소의 비등열전달 특성에 대한 실험적 연구)

  • Seo, Mansu;Lee, Jisung;Kim, Junghan;Kang, Sunil
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.24 no.3
    • /
    • pp.59-70
    • /
    • 2020
  • Obtaining external forced convection heat transfer from bubble boiling and validating it with experimental results using cryogenic liquids are suggested to derive total heat transfer coefficient with pool boiling condition in the case of coil type heat exchanger with a bundle of tubes and to overcome the limitation of using the empirical correlation. Experiment is conducted with pool boiling heat transfer of saturate liquid nitrogen with helical coil type heat exchanger using liquid oxygen as hot stream fluid. Experimentally measured heat transfer coefficient is well-agreed with the estimated curve considering nucleate boiling and forced convection induced by bubble rise.

Optimized Flooding Analysis Method for Compartment for Nuclear Power Plant (원전 격실에 대한 최적 침수분석 방법)

  • Song, Dong-Soo;Kim, Sang-Yeol
    • Journal of Energy Engineering
    • /
    • v.21 no.1
    • /
    • pp.75-80
    • /
    • 2012
  • In this paper a realistic bounding method for flooding analysis following rupture of large size of thanks and piping is defined. Mass and energy release during main feedwater line break accident is analyzed with RETRAN code. It is modeled that the main feed water control valve is closed in 5.0 seconds after reactor trip. In result of the analysis, largest mass and energy is discharged at 70% reactor power. The flood sources for main feedwater room are calculated when piping failure occurs in the high energy line and medium energy line. Based on the result of flood level (1.43m), it is investigated that all of the safety-related environmental qualification equipments are well located above the flood level.

Evaluation of Corrosion Protection Efficiency and Analysis of Damage Detectability in Buried Pipes of a Nuclear Power Plant with 3D FEM (3D FEM 모델링을 이용한 원전 매설배관의 방식성능 평가 및 결함탐지능 분석)

  • Chang, Hyun Young;Park, Heung Bae;Kim, Ki Tae;Kim, Young Sik;Jang, Yoon Young
    • Transactions of the Korean Society of Pressure Vessels and Piping
    • /
    • v.11 no.2
    • /
    • pp.61-67
    • /
    • 2015
  • 3D FEM modeling based on 3D CAD data has been performed to evaluate the efficiency of CP system in a real operating nuclear power plant. The results of it successfully produced sophisticated profiles of electrolytic potential and current distributions in the soil of an interested area. This technology is expected to be a breakthrough for detection technology of damages on buried pipes when it comes into combining with a brand of area potential earth current (APEC) and ground penetrated radar (GPR) technologies. 2D current distribution and 2D current vectors on the earth surface from the APEC survey will be used as boundary conditions with exact 3D geometry data resulting in visualization of locations and extents of corrosion damages on the buried pipes in nuclear power plants.