• 제목/요약/키워드: flow distribution

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고유동 강섬유보강 모르타르의 유동에 따른 섬유의 방향성 분포특성 변화의 예측 (Numerical Simulation for the Variation of the Fiber Orientation Distribution according to the Flow of High-Flow Steel-Fiber Reinforced Mortar)

  • 강수태;김진근
    • 한국전산구조공학회논문집
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    • 제22권6호
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    • pp.639-646
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    • 2009
  • 고유동 강섬유보강 모르타르는 타설과정에서 특정한 섬유 방향성 분포를 가질 수 있으며, 이에 따라 재료의 인장거동 특성에 영향을 미칠 수 있다. 본 연구에서는 고유동 강섬유보강 모르타르의 타설단계에서의 유동에 따른 강섬유의 섬유 방향성 분포의 변화를 해석적으로 구하였다. 해석결과에 따르면 180mm 간격으로 나란히 놓여진 두 평판 사이에 흐르는 모르 타르의 전단흐름에 의한 섬유의 방향성 변화는 초기 150mm이내에서 크게 발생하는 것을 확인할 수 있었으며, 이후에서는 방향성 분포의 경향은 크게 변하지 않으며, 다만 흐름방향에 나란한 섬유의 밀도가 집중적으로 커지는 것을 볼 수 있었다. 섬유의 방향성과 섬유보강 복합체의 인장거동과 밀접한 관련성을 고려할 때, 이와 같은 방향성의 예측을 바탕으로 유동에 따른 고유동 강섬유보강 모르타르의 인장거동 변화의 예측이 가능할 것이다.

Flow performance of cryomodules in C-ADS Injector II

  • WAN, Yu-Qin;HAN, Yan-Ning;Zhang, Jun-Hui;Li, Chao
    • 한국초전도ㆍ저온공학회논문지
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    • 제24권3호
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    • pp.74-78
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    • 2022
  • Two β=0.10 cryomodules are required for the China Accelerator Driven Subcritical System (C-ADS) injector II accelerator. Flow design is of great importance in the performance of cryomodules, including thermal design, flow distribution, pressure drop and so on. This paper will study convection heat transfer of helium and relation among the pipe diameter, mass flow rate and Reynolds number. Furthermore, the influence of flow geometries on pressure drop and flow distribution will also be done. It was found that the theoretical flow distribution were in good agreement with the experimental data.

객체지향기법을 이용한 배전계통 조류계산 (Power-Flow by using OOP in Distribution Power System)

  • 서규석;주재현
    • 조명전기설비학회논문지
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    • 제24권9호
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    • pp.20-25
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    • 2010
  • This paper mainly proposes power flow algorithm using OOP(Object-Oriented Programming) in distribution power system. Because the most power system problems are calculated from power flow, it is an important part in power system. Recently, new power generation facilities are steadily installed in the distribution system connected with Microgrid which has been gaining popularity among the industry and utilities. This paper contributes to improve the power flow algorithm using OOP for efficient power flow according to the distribution system configuration fluctuated frequently.

Estimating Suitable Probability Distribution Function for Multimodal Traffic Distribution Function

  • Yoo, Sang-Lok;Jeong, Jae-Yong;Yim, Jeong-Bin
    • 해양환경안전학회지
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    • 제21권3호
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    • pp.253-258
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    • 2015
  • The purpose of this study is to find suitable probability distribution function of complex distribution data like multimodal. Normal distribution is broadly used to assume probability distribution function. However, complex distribution data like multimodal are very hard to be estimated by using normal distribution function only, and there might be errors when other distribution functions including normal distribution function are used. In this study, we experimented to find fit probability distribution function in multimodal area, by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. By using chi-squared statistic, gaussian mixture model(GMM) is the fittest model rather than other distribution functions, such as extreme value, generalized extreme value, logistic, and normal distribution. GMM was found to the fit model regard to multimodal data of maritime traffic flow distribution. Probability density function for collision probability and traffic flow distribution will be calculated much precisely in the future.

취출구를 가진 덕트의 공기분배장치 설계 (Design Of Air-Distribution System in a Duct)

  • 강형선;조병기;고영하
    • Journal of Advanced Marine Engineering and Technology
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    • 제31권8호
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    • pp.954-960
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    • 2007
  • The purpose of this paper is to obtain design method of air-distribution system. Air-distribution system is composed of blower, duct, diffusers and measuring equipment. The air-flow rate from each diffuser is not equal. The air-flow rate is calculated with the combined equations which are Bernoulli's equation, continuity equation and minor loss equations. Inlet condition and outlet condition are adapted in each duct system. Then square difference between function of maximum air-flow rate and minimum air-flow rate is used as an object function. Area of diffuser and velocity are established as constraints. To minimize the object function, the optimization method is used. After optimization the design variables are selected under satisfaction of constraints. The air-distribution system is calculated again with the result of optimized design variable. It is shown that the air-distribution system has the equal air-flow rate from diffusers.

가호기 건조 시스템에서 수치적 유동해석 (Numerical Analysis of the Flow in the Drying Chamber of a Sizing Machine)

  • 이진호;김수연
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 1996년도 추계 학술발표회
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    • pp.29-34
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    • 1996
  • In the present paper, the flow distribution in the hot air drying chamber of a sizing machine was numerically analyzed with respect to the geometries of the intake duct to obtain the more uniform flow distribution in the chamber. The result shows that the velocity distribution in the inlet of the chamber was significantly dependent on the the geometry of the intake duct. The degree of the non-uniformity in the chamber was reduced as the incident angle of the intake duct became to be smaller.

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다중블록실험과 전산유체해석을 통한 블록형 초고온가스로의 노심우회유량 평가 (ASSESSMENT of CORE BYPASS FLOW IN A PRISMATIC VERY HIGH TEMPERATURE REACTOR BY USING MULTI-BLOCK EXPERIMENT and CFD ANALYSIS)

  • 윤수종;이정훈;김민환;박군철
    • 한국전산유체공학회지
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    • 제16권3호
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    • pp.95-103
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    • 2011
  • In the block type VHTR core, there are inevitable gaps among core blocks for the installation and refueling of the fuel blocks. These gaps are called bypass gap and the bypass flow is defined as a coolant flows through the bypass gap. Distribution of core bypass flow varies according to the reactor operation since the graphite core blocks are deformed by the fast neutron irradiation and thermal expansion. Furthermore, the cross-flow through an interfacial gap between the stacked blocks causes flow mixing between the coolant holes and bypass gap, so that complicated flow distribution occurs in the core. Since the bypass flow affects core thermal margin and reactor efficiency, accurate prediction and evaluation of the core bypass flow are very important. In this regard, experimental and computational studies were carried out to evaluate the core bypass flow distribution. A multi-block experimental apparatus was constructed to measure flow and pressure distribution. Multi-block effect such as cross flow phenomenon was investigated in the experiment. The experimental data were used to validate a CFD model foranalysis of bypass flow characteristics in detail.

Impact of axial power distribution on thermal-hydraulic characteristics for thermionic reactor

  • Dai, Zhiwen;Wang, Chenglong;Zhang, Dalin;Tian, Wenxi;Qiu, Suizheng;Su, G.H.
    • Nuclear Engineering and Technology
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    • 제53권12호
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    • pp.3910-3917
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    • 2021
  • Reactor fuel's power distribution plays a vital role in designing the new generation thermionic Space Reactor Power Systems (SRPS). In this paper, the 1/12th SPACE-R's full reactor core was numerically analyzed with two kinds of different axial power distribution, to identify their impacts on thermal-hydraulic and thermoelectric characteristics. In the benchmark study, the maximum error between numerical results and existing data or design values ranged from 0.2 to 2.2%. Four main conclusions were obtained in the numerical analysis: a) The axial power distribution has less impact on coolant temperature. b) Axial power distribution influenced the emitter temperature distribution a lot, when the core power was cosine distributed, the maximum temperature of the emitter was 194 K higher than that of the uniform power distribution. c) Comparing to the cosine axial power distribution, the uniform axial power distribution would make the maximum temperature in each component of the reactor core much lower, reducing the requirements for core fuel material. d) Voltage and current distribution were similar to the axial electrode temperature distribution, and the axial power distribution has little effect on the output power.

A Review on the Regionalization Methodology for Core Inlet Flow Distribution Map

  • Lee, Byung-Jin;Jang, Ho-Cheol;Cheong, Jong-Sik;Baik, Se-Jin;Park, Young-Sheop
    • Nuclear Engineering and Technology
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    • 제33권4호
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    • pp.441-456
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    • 2001
  • ABB-CE's regionalization methodology for the core inlet flow distribution map is reviewed. This methodology merges the test data of fuel assembly locations which are either in symmetry or strongly correlated with others. It increases the number of available test data for each regional flow factor It makes up effectively for the deficiency due to limited number of test data. It also contributes to making the core inlet flow distribution smoother not only locally but also over the entire core, and to relieving the impacts of test errors that may happen due to some do- calibrated local pressure measurement taps. As a result, the core inlet How distribution data becomes more statistically useful and thus the conservatism involved in handling the core inlet flow factors for the thermal margin analysis is expected to be reduced. Meanwhile, the regionalized map may lose the unique local characteristics in core inlet flow distribution too much. By an alternative approach introduced in the present work, it is shown that such a disadvantage can be mitigated somewhat if the engineering judgement is made more

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