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고정밀 2상유동 액막두께 측정을 위한 연성회로기판 기반 3-전극 센서 개발
이규병 ( Kyu Byoung Lee ),김종록 ( Jong Rok Kim ),어동진 ( Dong Jin Euh ),박군철 ( Goon Cherl Park ),조형규 ( Hyoung Kyu Cho ) 한국센서학회 2016 센서학회지 Vol.25 No.1
To understand a two-phase flow, a liquid film thickness is one of the important factors. A lot of researches have been performed to measure liquid film thickness with various approaches. Recently, an electrical conductance method which uses the conductivity of the liquid film has been widely applied on measuring the liquid film thickness. Though the electrical method has an advantage in high spatial resolution, as the conductivity of liquid can be affected by its temperature variation, the conventional electrical conductance methods have a limitation in being applied on varying temperature conditions where a heat transfer is involved. The purpose of this study is to develop a three-ring liquid film sensor that overcomes the limitation of the conventional method. The three-ring conductance method can measure the film thickness regardless of temperature variation by compensating the change of liquid conductivity. Considering its application on a wide range of conditions such as high temperature or curved surfaces, the sensor was fabricated on flexible printed circuit board (FPCB) in this study. This paper presents the concept of the measurement method, design procedure, prototype sensor fabrication and calibration results.
김종록(Jongrok Kim),어동진(Dong Jin Euh),조형규(Hyoung-Kyu Cho) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
The real time measurement of the void fraction, which is one of the parameters of the two-phase flow that determines the pressure drop and heat transfer coefficient in a fluidic system, is very important. The time resolution that achieved by employing the conductance method that can be used to calculate the liquid film thickness from the electric conductivity of the fluid is high because the electric characteristics are taken into account. Therefore, this method can be employed to accurately measure the film thickness without distortion of flow in real time by placing electrodes on the walls.Coney analytically studied a three probe conductance meter, which can void an error by variation of liquid temperature. The aim of this study is to compare the experimental signal of three probe conductance meter and the analytical predicted signal and to experimentally verify the robustness of a three probe conductance meter to variations in the electric conductivity of the fluid.
연성회로기판 기반 수평전열관 표면의 비등기포거동 가시화 실험 연구
김재순(Jae Soon Kim),김유나(Yu-Na Kim),박군철(Goon-Cherl Park),조형규(Hyoung Kyu Cho) 한국가시화정보학회 2016 한국가시화정보학회지 Vol.14 No.2
The Passive Auxiliary Feedwater System(PAFS) is one of the advanced safety concepts adopted in the Advanced Power Reactor Plus(APR+). To validate the operational performance of the PAFS, detailed understanding of a boiling heat transfer on horizontal tube outside is of great importance. Especially, in the mechanistic boiling heat transfer model, it is important to visualize the phenomena but there are some limitations with conventional experimental approaches. In the present study, we devised a heater based on the Flexible Printed Circuit Board (FPCB) for a more comprehensive visualization and subsequently, a digital image processing technique for the bubble motion measurement was established. Using the measurement technique, important parameters of the nucleate boiling are analyzed.