• Title/Summary/Keyword: Fuel Flow

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Flow Analysis of the Tube Type Marine Auto-Backwashing Fuel Oil Filter (튜브형 박용 자동역세 연료유 필터 내부의 유동해석)

  • Yang, Jang-Sik;Kim, Bong-Hwan;Park, Young-Bum
    • Journal of Advanced Marine Engineering and Technology
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    • v.33 no.4
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    • pp.578-587
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    • 2009
  • In this paper, the characteristics of incompressible flow in a tube type marine fuel oil filter have been investigated. Fluent program has been used to obtain the solutions for the problems of three-dimensional, turbulent fuel oil flow in a filtering system. The inlet flow field is assumed to be uniform. The velocity and pressure distributions were obtained using Darcy's law. The increase of inlet velocity for cleaning fuel oil may cause some problems like vibration of the filter element. It was also required to consider the distribution of cleaning velocity because the worst distribution of cleaning velocity may cause the local insufficient cleaning effect and furthermore the effective filtration area can be reduced. The simulated results show that the computer code can be successfully applied for simulation of the complex base oil flow through the porous media. This paper could be applied to the design of auto-backwashing filtering system as design factor.

The Thermal-Hydraulic Effects of Thimble Plug Removal for Westinghouse type PWR Plants

  • B. S. Jun;Park, E. J.;Kim, K. H.;Park, B. S.;K. L. Jeon
    • Proceedings of the Korean Nuclear Society Conference
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    • 1996.05b
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    • pp.166-172
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    • 1996
  • The thermal-hydraulic effects of removing the RCC guide thimble plugs are evaluated for Westinghouse type PWR plants as a part of feasibility study: core outlet loss coefficient, thimble bypass flow, and best estimate flow. It is resulted that the best estimate thimble bypass flow increases about by 2% and the best estimate flow increase approximately by 1.2%. The resulting DNBR penalties can be covered within the current DNBR margin. Accident analyses are also investigated and the dropped rod transient is shown to be limiting and relatively sensitive to bypass flow variation.

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Internal Flow Analysis of a Fuel Pressurized Blower for Fuel Cell System (연료전지용 연료승압 블로어 내부유동장 평가)

  • Choi, Ka-Ram;Jang, Choon-Man
    • New & Renewable Energy
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    • v.7 no.3
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    • pp.29-35
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    • 2011
  • This paper describes an internal flow characteristics of a fuel pressurized blower, used for 1kW domestic fuel cell system. To analyze the flow field inside the diaphragm cavity, compressible unsteady numerical simulation is introduced. SST model with scalable wall function is employed to estimate the eddy viscosity. Moving mesh system is applied to the numerical analysis for describing the volume change of a diaphragm cavity in time. Throughout numerical simulation with the modeling of the inlet and outlet valves in a diaphragm cavity, unsteady nature of an internal flow is successfully analyzed. Force variations on the lower plate of a diaphragm cavity are evaluated in time. It is found that the driving force at the suction stage of a diaphragm cavity is more necessary than that at the discharging stage.

A Numerical Analysis on Transient Fuel Temperatures in a Military Aircraft with Additional Fuel Supplies and Return (추가연료 공급,회송량에 따른 항공기내 연료온도 변화에 대한 수치해석적 연구)

  • Kim,Yeong-Jun;Kim,Chang-Nyeong;Kim,Cheol-In
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.1
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    • pp.73-84
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    • 2003
  • A transient analysis on fuel temperatures in an aircraft was studied using the finite difference method. Numerical calculation was performed by an explicit method of modified Dufort-Frankel scheme. Among various missions, close air support mission was considered with 20% hot day ambient condition in subsonic region. The aircraft was assumed to be in turbulent flow. The fuel system model with additional fuel supplies and return concept was considered. As a result of this analysis, the fuel tank temperatures have increased with the increase of the additional fuel supplies. In contrast to tank temperatures, the fuel temperature at the engine inlet has decreased with the increase of additional fuel supplies except in some in-flight phases having high engine fuel flow. From this analysis, the fuel system with the additional fuel supplies and return concept has been shown to be an effective method to decrease the engine inlet fuel temperature. Also, it has been shown that fuel flow rate through fuel/oil heat exchanger is a key factor influencing fuel temperature.

Flow and Convective Heat Transfer Analysis Using RANS for A Wire-Wrapped Fuel Assembly

  • Ahmad, Imteyaz;Kim, Kwang-Yong
    • Journal of Mechanical Science and Technology
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    • v.20 no.9
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    • pp.1514-1524
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    • 2006
  • This work presents the three-dimensional analysis of flow and heat transfer performed for a wire-wrapped fuel assembly of liquid metal reactor using Reynolds-averaged Wavier-Stokes analysis in conjunction with 557 model as a turbulence closure. The whole fuel assembly has been analyzed for one period of the wire-spacer using periodic boundary conditions at inlet and outlet of the calculation domain. Three different assemblies, two 7-pin wire-spacer fuel assemblies and one bare rod bundle, apart from the pressure drop calculations for a 19-pin case, have been analyzed. Individual as well as a comparative analysis of the flow field and heat transfer have been discussed. Also, discussed is the position of hot spots observed in the wire-spacer fuel assembly. The flow field in the subchannels of a bare rod bundle and a wire-spacer fuel assembly is found to be different. A directional temperature gradient is found to exist in the subchannels of a wire-spacer fuel assembly Local Nusselt number in the subchannels of wire-spacer fuel assemblies is found to vary according to the wire-wrap position while in case of bare rod bundle, it's found to be constant.

A Study on the Combustion Characteristics and the Control on the Fuel Flow Rate of LPG Intake Port Injection Engine (흡기포트 분사식 LPG 엔진의 연료량 제어 및 연소 특성에 관한 연구)

  • 김우석;이종화;정창현
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.6
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    • pp.31-39
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    • 2000
  • In this paper, characteristics of a port injection type LPG fuel system were investigated to adopt the system to a spark ignition engine through rig test. Engine combustion characteristics for limited conditions and the precise control method of LPG fuel supply were also studied. As a basic experiment, the effects and the relationships of parameters such as orifice area, fuel delivery pressure, fuel temperature and flow coefficient were established. From this, one dimensional compressible flow equation can be applied to control gaseous fuel flow rate by setting pressure difference between vaporizer and manifold to a certain range, for example about 1.2 bar in a naturally aspirated engine. The combustion analysis results of LPG engine were also compared with those of gasoline engine according to spark timing and load change. At part load and stoichiometric condition, the MBT spark timing of LPG fueled engine is retarded by 2$^{\circ}$ - 4$^{\circ}$CA compared to that of gasoline engine. On the contrary, the spark timing of LPG fueled engine can be advanced by 5$^{\circ}$- 10$^{\circ}$ CA at WOT, which results from higher Octane Number and burned fraction of LPG fuel compared to gasoline.

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FARE Device Operational Characteristics of Remote Controlled Fuelling Machine at Wolsong NPP

  • I. Namgung;Lee, S.K.;Kim, Y.B.
    • Nuclear Engineering and Technology
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    • v.34 no.5
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    • pp.468-481
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    • 2002
  • There are 4 CANDU6 type reactors operating at Wolsong site. For fuelling operation of certain fuel channels (with flow less than 21.5 kg/s) a FARE flow Assist Ram Extension) device is used. During the refuelling operation, two remote controlled F/Ms (Fuelling Machines) are attached to a designated fuel channel and carry out refuelling job. The upstream F/M inserts new fuel bundles into the fuel channel while the downstream F/M discharges spent fuel bundles. In order to assist fuelling operation of channels that has lower coolant How rate, the FARE device is used instead of F/M C-ram to push the fuel bundle string. The FARE device is essentially a How restricting element that produces enough drag force to push the fuel bundle string toward downstream F/M. Channels that require the use of FARE device for refuelling are located along the outside perimeter of reactor. This paper presents the FARE device design feature, steady state hydraulic and operational characteristics and behavior of the device when coupled with fuel bundle string during fuelling operation. The study showed that the steady state performance of FARE device meets the design objective that was confirmed by downstream F/M C-ram force to be positive.

Performance Predictions of the Planar-type Solid Oxide Fuel Cell with Computational Flow Analysis (I) - Isothermal Model - (유동 해석을 이용한 평판형 고체 산화물 연료전지의 성능 특성 분석 (I) - 등온 모델 -)

  • Hyun, Hee-Chul;Sohn, Jeong L.;Lee, Joon-Sik;Ro, Sung-Tack
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.5
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    • pp.635-643
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    • 2003
  • Parametric study for the analysis of performance characteristics of a planar -type solid oxide fuel cell(SOFC) using computational flow analysis is conducted. A planar -type SOFC, which is composed by two gas channels (fuel and ai.) and one set of anode-electrolyte-cathode assembly, is modeled as a two -dimensional isothermal case. Results of computational analysis of flow field including distributions of mass fractions in gas channels are used to the performance analysis of the fuel cell. Flow analysis makes it possible to consider current density distributions along the length of the cell in the process of performance analysis of the SOFC. As results of parametric study, it is found that the mole fraction of fuel at the inlet of fuel channel, operating pressure and temperature are closely related to the performance characteristics of SOFC.

The Effect of Water Flow on Fretting Wear of the Nuclear Fuel Cladding Tubes against the Supporting Grids (핵연료 피복관과 지지격자 사이에 발생하는 프레팅 마멸에 미치는 유동의 영향)

  • Lee, Young-Ze;Kim, Jin-Seon;Park, Se-Min;Park, Dong-Shin
    • Tribology and Lubricants
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    • v.24 no.4
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    • pp.186-189
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    • 2008
  • The flow induced vibration in the nuclear fuel assembly causes the fretting wear between the fuel cladding tubes and the supporting grids. The reduction in tube thickness due to the fretting wear could be related to the serious damage on nuclear fuel assembly. In this paper, the effect of the water flow on fretting wear of nuclear fuel cladding tube against supporting grid was investigated through the fretting wear tester with water spout equipment. The test results were compared with the data conducted in the stationary water. At stationary water environment the wear debris was trapped between fretting surfaces, and then the fretting wear occurred by three-body abrasion. However, in the case of water flow, the two-body abrasive wear was the dominant wear mechanism, because the wear debris was easily removed by water flow.

DEVELOPMENT AND VALIDATION OF A NUCLEAR FUEL CYCLE ANALYSIS TOOL: A FUTURE CODE

  • Kim, S.K.;Ko, W.I.;Lee, Yoon Hee
    • Nuclear Engineering and Technology
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    • v.45 no.5
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    • pp.665-674
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    • 2013
  • This paper presents the development and validation methods of the FUTURE (FUel cycle analysis Tool for nUcleaR Energy) code, which was developed for a dynamic material flow evaluation and economic analysis of the nuclear fuel cycle. This code enables an evaluation of a nuclear material flow and its economy for diverse nuclear fuel cycles based on a predictable scenario. The most notable virtue of this FUTURE code, which was developed using C# and MICROSOFT SQL DBMS, is that a program user can design a nuclear fuel cycle process easily using a standard process on the canvas screen through a drag-and-drop method. From the user's point of view, this code is very easy to use thanks to its high flexibility. In addition, the new code also enables the maintenance of data integrity by constructing a database environment of the results of the nuclear fuel cycle analyses.