• 제목/요약/키워드: CFD (computational Fluid Dynamics)

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3차원 CFD 시뮬레이션을 활용한 고분자전해질 연료전지 스택의 매니폴드 크기 최적화 (Optimal Sizing of the Manifolds in a PEM Fuel Cell Stack using Three-Dimensional CFD Simulations)

  • 정지훈;한인수;신현길
    • 한국수소및신에너지학회논문집
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    • 제24권5호
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    • pp.386-392
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    • 2013
  • Polymer electrolyte membrane (PEM) fuel cell stacks are constructed by stacking several to hundreds of unit cells depending on their power outputs required. Fuel and oxidant are distributed to each cell of a stack through so-called manifolds during its operation. In designing a stack, if the manifold sizes are too small, the fuel and oxidant would be maldistributed among the cells. On the contrary, the volume of the stack would be too large if the manifolds are oversized. In this study, we present a three-dimensional computational fluid dynamics (CFD) model with a geometrically simplified flow-field to optimize the size of the manifolds of a stack. The flow-field of the stack was simplified as a straight channel filled with porous media to reduce the number of computational meshes required for CFD simulations. Using the CFD model, we determined the size of the oxidant manifold of a 30 kW-class PEM fuel cell stack that comprises 99 cells. The stack with the optimal manifold size showed a quite uniform distribution of the cell voltages across the entire cells.

정보통신기술과 전산유체역학 (Information Technology and Computational Fluid Dynamics)

  • 조금원;박형우;이상산
    • 한국전산유체공학회지
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    • 제6권3호
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    • pp.51-56
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    • 2001
  • As IT(Information Technology) has been developing, an application engineering is advanced so quickly. Especially, CFD field that is influenced greatly by Computing Power is an outstanding example. In this paper, it says a research tendency of the KISTI Supercomputing Center that performs the CFD research based on IT. The representative researches are the National Grid Project, TeraCluster Construction and development and a supporting plan for Supercomputer users' parallelization.

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CFD을 이용한 프란시스 수차의 내부유동 해석 (Performance Analysis of Francis Turbines by CFD)

  • 최현준;황영철;김유택;남청도;이영호
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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    • pp.191.2-191.2
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    • 2010
  • The conventional method to assess turbine performance is its model testing which becomes costly and time consuming for several design alternatives in design optimization. Computational fluid dynamics (CFD) has become a cost effective tool for predicting detailed flow information in turbine space to enable the selection of best design. In the present paper, Francis turbine of commercial small hydropower plants which is under 70kw is investigated. Solutions are investigated with respect to the hydraulic characteristics against an outward angle of guide vane, the number of guide vane and head (inlet velocity). By suitable modification of the runner shape, low pressure zone on the leading edge can be reduced. If the entire runner is to be optimized in this manner, flow simulation tests have to be carried out on a series of different geometrical shape.

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Flow Characteristics of Polluted Air in a Rectangular Tunnel using PIV and CFD

  • Lee, Yong-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • 제36권5호
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    • pp.609-617
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    • 2012
  • The flow characteristics of polluted air are analysed by comparing the results obtained from PIV(Particle Image Velocimetry) experiment and CFD(Computational Fluid Dynamics) commercial code. In order to simulate the polluted air flow, the olive oil has been used as tracer particles with the kinematic viscosity of air, $1.51{\times}10^{-5}m^2/s$. The investigation has done in the range of Reynolds numbers of 870, 1730 and 2890 due to the inlet flow velocities of 0.3, 0.6, and 1.0 m/s, respectively. The average velocity and the pressure distributions are comparatively discussed with respect to the three different Reynolds numbers. The results show that the outlet flow rates at three different Reynolds numbers are equivalent of 165 to 167 percent of the inlet ones. The pressure drop occurs in the model closed at both end sides and the highest pressures at each Reynolds number are positioned at the top of the tunnel between the inlet and outlet.

이중 수로 구조의 분배수로 내 다지점 유출 유량의 균등성 평가에 관한 연구 (Examining the Equality of Multi-Outlet Flow Rates within a Dual Open Channel)

  • 김성수;박노석;정우창;왕창근
    • 상하수도학회지
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    • 제26권3호
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    • pp.423-430
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    • 2012
  • This study was conducted to qualify the equality of the flow distribution from open channel between rapid mixing basin and flocculation basins in a domestic S_ water treatment plant, and to suggest a remedy for improving the equality. In order to evaluate the feasibility of the suggested remedy, computational fluid dynamics (CFD) technique are used, and for verifying the CFD simulation results tracer tests were carried out. From the results of CFD simulation and tracer tests, it was investigated that the modification of hydraulic structure in the distribution channel, which is to install the longitudinal orifice baffle in flow direction, could improve the equality of the flow distribution over 75%.

CFD에 의한 아파트 단지의 빌딩풍에 관한 사례연구 - 천안지역 2개 단지를 중심으로 - (Example Study on Building Wind of Apartment Complex by Computational Fluid Dynamics - About Two apartment Complex in Cheon-An Region -)

  • 노지웅
    • KIEAE Journal
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    • 제8권4호
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    • pp.37-42
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    • 2008
  • In the case that high-rise building is constructed, the surrounding wind velocity increase more than 50~100%. From this cause, many wind environmental problems can be occurred. For example, ordinary wind environmental disaster may be occurred in a region, or walking disturbed. In developed countries including USA, EU, and Japan, many efforts have been made for building wind prevention by grasping previously the effects before building constructed. But, We are bearing risk of wind environmental disaster because we have not enough recognition about building wind, and have not architectural prevention counterplans. This study aims to examine wind environmental characteristics of domestic apartment complex, and effective architectural counterplans. As the basic stage for this, we investigated pre-estimate tools and risk assessment methods of building wind in apartment complex, applied to two apart complex in Cheon-An region by CFD. As the result, serious damages were not presented. But, it is obvious that various architectural counterplans will be presented by this example researches.

CFD를 이용한 모바일기기용 고분자전해질 연료전지 성능해석 (The Performance Analysis of Polymer Electrolyte Membrane Fuel Cells for Mobile Devices using CFD)

  • 김병희;최종필;강대철;전병희
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.553-554
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    • 2006
  • This paper presents the effects of different operating parameters on the performance of a proton exchange membrane (PEM) fuel cell by a three-dimensional computational fluid dynamics (CFD) model. The effects of different operating parameters on the performance of PEM fuel cell studied using pure hydrogen on the anode side and air on the cathode side. The various parameters are temperatures, pressures, humidification of the gas steams and various combinations of these parameters. In addition, geometrical and material parameters such as the gas diffusion layer (GDL) thickness and porosity as well as the ratio between the channel width and the land area were investigated.

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Numerical Simulation of Flow and Dross Particle Transfer in a 55% Al-Zn Pot

  • Kim, Hwang Suk;Kim, Jong Gi;Yoon, Seung Chae;Im, Hee Joong;Moon, Man Been
    • Corrosion Science and Technology
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    • 제11권3호
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    • pp.71-76
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    • 2012
  • Computational fluid dynamics (CFD) is nowadays a powerful and reliable tool for simulating different flow processes and temperature. CFD is used to analyze the various pot geometries and operative variables in 55% Al-Zn pot of CGL. In this research, different strip velocities were assumed and then shown the flow pattern in the pot that was similar in the different strip velocities. Temperature distribution in the pot depended on inductors and inlet strip temperature at the steady condition. Generation of dross particles and transport models were considered to describe dross particles evolution inside the pot. In order to observe dross influence by scrap location, dross particles were generated upon the sink roll. Floating time of dross particles is different by scraper locations above the sink roll.

유공벽을 이용한 우류식 염소접촉조 사류 저감 방안 연구 (Study on Methodology for Reducing Dead Zone Flow within Chlorine Contactor Installing Porous Baffles)

  • 박현오;박노석;차민환;김사동;원찬희
    • 상하수도학회지
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    • 제24권5호
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    • pp.519-525
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    • 2010
  • From the results of tracer test for the existing chlorine contactor in Y water treatment plant, $T_{10}$ and $T_{10}$/T were calculated as 130 min and 0.16, respectively. Therefore it required the modification schemes for improving hydraulic efficiency, surrogated by T10 and $T_{10}$/T, and disinfection performance. In this study, in order to reduce dead zone within contactor, the installation of porous baffles in the near of each corner was suggested and verified using transient CFD(Computational Fluid Dynamics) simulation technique and tracer tests on dynamic condition. From the results of simulation and tracer tests, it was revealed that porous baffles installed have been effective to reduce dead zone within contactor, and increase plug flow fraction.

CFD해석에 의한 침실 호흡역의 환기효율 분석 (Analysis on ventilation efficiency by CFD simulation for breathing zone in bed room)

  • 유복희;윤정숙
    • KIEAE Journal
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    • 제2권3호
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    • pp.11-16
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    • 2002
  • Indoor air environment is one of the most important factors that affect resident's health and comfort level. In this paper, the influence of ventilation efficiency with different types of furniture arrangement at breathing zone in a room was analyzed by numerical simulation based on computational fluid dynamics(CFD). The furniture layout of students' bedroom have been classified by three different patterns so that SVE3(scale for ventilation efficiency3) in the rooms was analyzed for air flow distribution. According to the results of the study, SVE3 has the maximum value in spaces between furnitures and each comer of the room. The furniture arrangement influences the ventilation efficiency. It was con finned that ventilation effective in a room is not uniformly distributed as compared the breathing zone with all the area in a room. It means that a study of ventilation efficiency was considered relatively with target zone(a residential or breathing zone) and all the area in a space.