• Title, Summary, Keyword: Neutron Imaging Technique

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Visualization of 2-Phase Flow at Heat Pipe using Neutron Imaging Technique (중성자 영상법을 이용한 Heat Pipe 내의 이상유동 가시화)

  • Kim, TaeJoo;Park, SuJi;Kim, JongYul;Doh, SeungWoo
    • Journal of the Korean Society of Visualization
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    • v.14 no.3
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    • pp.15-21
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    • 2016
  • The circular and flat heat pipe were experimentally investigated by using neutron imaging technique. This experimental study was performed at the DINGO of OPAL research reactor, Australia. The diameter of the circular heat pipe is 10 mm and the dimension of flat is $10(width){\times}3(thickness)mm2$, respectively. We used the distilled water as a coolant. The coolant distributions and 2-phase flow patterns were measured under heating conditions. Experimental results show that neutron imaging technique is a good tool to visualize the 2-phase flow and phenomena in the heat pipe. The coolant distributions and 2-phase flow patterns depend on installation posture of the heat pipe and volume ratio of the coolant. Finally, it was discussed to calculate the void fraction by neutron imaging technique.

Experimental Approach for Water Discharge Characteristics at PEMFC by using Neutron Imaging Technique considered Neutron Flux and Linear Attenuation Coefficient of Thermal Neutron Correction at NRF, HANARO (중성자속 및 선형 흡수 계수 보정을 고려한 중성자영상법을 이용한 PEMFC 내의 물 배출 특성에 관한 실험적 연구)

  • Kim, Tae-Joo;Kim, Jong-Rok;Kim, Moo-Hwan;Sim, Cheul-Muu
    • Proceedings of the KSME Conference
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    • pp.3418-3422
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    • 2007
  • The neutron imaging technique was used to investigate the water discharge characteristics at PEMFC. Prior to investigation of water discharge characteristics, the linear attenuation coefficient for water at Neutron Radiography Facility (NRF) was calibrated. The feasibility test apparatus was consisted of pressurized air and water in order to simulate the actual operating PEMFC. The feasibility tests have been performed at 1-parallel serpentine type with 100 $cm^2$ active area and different air flow rate (1, 2, and 4 lpm). The total water volume variations at each condition were calculated from the neutron images. The water at channel is well discharged as soon as supplying the pressurized air into the PEMFC. However, because the water at MEA isn't removed the total water volume is constant after 150. Therefore more effective method is needed in order to discharge water at MEA, and the neutron imaging technique is helpful for it.

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VISUALIZATION OF THE INTERNAL WATER DISTRIBUTION AT PEMFC USING NEUTRON IMAGING TECHNOLOGY: FEASIBILITY TEST AT HANARO

  • Kim Tae-Joo;Jung Yong-Mi;Kim Moo-Hwan;Sim Cheul-Muu;Lee Seung-Wook;Jeon Jin-Soo
    • Nuclear Engineering and Technology
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    • v.38 no.5
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    • pp.449-454
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    • 2006
  • Neutron imaging technique was used to investigate the water distribution and movement in Polymer Electrolyte Membrane Fuel Cell (PEMFC) at HANARO, KAERI. The Feasibility tests were performed in the first and second exposure rooms at the neutron radiography facility (NRF) at HANARO in order to check the ability of each exposure room, respectively. The feasibility test apparatus was composed of water and pressurized air before making up the actual test apparatus. Due to the low neutron intensity in the second exposure room, the exposure time was too long to investigate the transient phenomena of PEMFC. Although the exposure time was improved to 0.1 sec in the first exposure room, it was difficult to discriminate detail water movement at the channel due to the high noise level. Therefore, the experimental setup must be optimized according to the test conditions. Water discharge characteristics were investigated under different flow field geometries by using feasibility test apparatus and the neutron imaging technique. The water discharge characteristics of a 3-parallel serpentine are superior to those of a 1-parallel serpentine, but water at Membrane Electrode Assembly (MEA) was not removed, regardless of the flow field type.

Visualization of Water Distribution in Cathode Side of a Direct Methanol Fuel Cell Using Neutron Radiography (중성자 라디오그래피 방법을 이용한 직접 메탄올 연료전지 공기극의 내부 물 분포 가시화)

  • Je, Jun-Ho;Doh, Sung-Woo;Kim, Tae-Joo;Kim, Jong-Rok;Xie, Xiaofeng;Kim, Moo-Hwan
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.10
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    • pp.965-970
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    • 2012
  • In this study, the water distribution in the cathode side of a direct methanol fuel cell (DMFC) is visualized using a neutron imaging technique at the Neutron Radiography Facility (NRF), KAERI. It is difficult to quantify the water content in the cathode side because of $CO_2$ gas. A compared open circuit voltage (OCV) image, relative $CO_2$, and water distribution can be visualized by the neutron imaging technique. This means that the neutron imaging technique is useful for the optimization of the flow field design and the establishment of water management, and, in turn, for the improvement of the cell performance.

EXPERIMENTAL APPROACHES FOR WATER DISCHARGE CHARACTERISTICS IN PEMFC USING NEUTRON IMAGING TECHNIQUE AT CONRAD, HMI

  • Kim, Tae-Joo;Kim, Jong-Rok;Sim, Cheul-Muu;Lee, Sung-Ho;Son, Young-Jin;Kim, Moo-Hwan
    • Nuclear Engineering and Technology
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    • v.41 no.1
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    • pp.135-142
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    • 2009
  • In this investigation, we prepared a 1 and 3-parallel serpentine single PEMFC, which has an active area of $100\;cm^2$ and a flow channel cross section of $1{\times}1mm$. Distribution and transport of water in a non-operating PEMFC were observed by varying flow types and the flow rates (250, 400, and 850 cc/min). This investigation was performed at the neutron imaging facility at the CO1d Neutron RAdiography facility (CONRAD), HMI, Germany of which the collimation ratio and neutron fluence rate are 250, $1{\times}10^{6}n/s/cm^2$, respectively. The neutron image was continuously recorded by a scintillator and lens-CCD coupled detector system every 10 seconds. It has been observed that although the distilled water was supplied into the cathode channel only, the neutron image showed a water movement from the cathode to the anode channel. The water at the cathode channel was completely discharged as soon as the pressurized air was supplied. But the water at the anode channel was not easily removed by the pressurized air except for the 3-parallel serpentine type with 850cc/min of air flow rate. Moreover, the water at the MEA wasn't removed for any of the cases.

Visualization of Crust in Metallic Piping Through Real-Time Neutron Radiography Obtained with Low Intensity Thermal Neutron Flux

  • Luiz, Leandro C.;Ferreira, Francisco J.O.;Crispim, Verginia R.
    • Nuclear Engineering and Technology
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    • v.49 no.4
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    • pp.781-786
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    • 2017
  • The presence of crust on the inner walls of metallic ducts impairs transportation because crust completely or partially hinders the passage of fluid to the processing unit and causes damage to equipment connected to the production line. Its localization is crucial. With the development of the electronic imaging system installed at the Argonauta/Nuclear Engineering Institute (IEN)/National Nuclear Energy Commission (CNEN) reactor, it became possible to visualize crust in the interior of metallic piping of small diameter using real-time neutron radiography images obtained with a low neutron flux. The obtained images showed the resistance offered by crust on the passage of water inside the pipe. No discrepancy of the flow profile at the bottom of the pipe, before the crust region, was registered. However, after the passage of liquid through the pipe, images of the disturbances of the flow were clear and discrepancies in the flow profile were steep. This shows that this technique added the assembled apparatus was efficient for the visualization of the crust and of the two-phase flows.