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Air Clearing Oscillation Produced by APR1400 Prototype Sparger
조석(Seok CHO),천세영(Se-Young CHUN),백원필(Won-Pil Baek),정흥준(Heung-Jun Chung),김유(Yoo Kim) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.5
KAERI has performed a series of experiments to investigate the performance of APR1400 prototype<br/> sparger in view of the dynamic load oscillation with the variation of test conditions such as discharged air<br/> mass, submergence of the sparger, valve opening time, and pool temperature during the air-clearing phase.<br/> The air mass and pool temperature are in the range of 0.8 ~ 1.5kg and 20 ~ 90oC, respectively. The valve<br/> opening time can be adjusted in the range of 0.6 ~ 1.7sec according to the POSRV operating conditions. The<br/> maximum positive pressure amplitude, which is observed at the bottom of the quench tank, is increased with<br/> the submergence depth and maximum header pressure of sparger. The valve opening time has a considerable<br/> effect on the maximum amplitude. As the opening time decreases, the maximum amplitude at the tank wall is<br/> increased. Air mass and pool temperature, however, have a weak effect on the maximum amplitude.<br/> Oscillation frequency is decreased with air mass in the range of 2.5 ~ 4.5Hz.
평균 양방향 튜브의 설계 최적화를 위한 FLUENT 코드해석
강경호(Kyong-Ho Kang),윤병조(Byong-Jo Yun),어동진(Dong-Jin Euh),백원필(Won-Pil Baek) 한국유체기계학회 2004 유체기계 연구개발 발표회 논문집 Vol.- No.-
Average Bi-directional flow tube was suggested to measure single and two phase flow rate. Its working principle is similar with Pitot tube, however, it makes it possible to eliminate the cooling system which is normally needed to prevent from flashing in the pressure impulse line of Pitot tube when it is used in the depressurization condition. 3-dimensional steady state flow analyses using FLUENT 5.4 code were performed to validate the application of the average bi-directional flow tube in case of water and air flow. In this study, sensitivity studies have been performed to optimize the design features of the average bi-directional flow tube which can be applied for the various experimental conditions. For Re numbers above 1000, the k values are nearly constant regardless of the Re numbers and flow types and calculation results and experimental data coincides quite well. The current FLUENT calculation results suggest that linearity of the k values in various design features of the average BDFT is highly promising, which means that it is quite reasonable to select the typical design of the average BDFT for the convenience of the experimental conditions.
FLUENT 5.4 코드를 이용한 양방향 유동 튜브에 대한 유동해석
강경호(Kyoung-Ho Kang),윤병조(Byung-Jo Yun),백원필(Won-Pil Baek) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
Flow analyses using FLUENT 5.4 code were performed to validate the application of the local bidirectional<br/> flow tube in case of water and air flow. In this study, sensitivity studies have been performed to<br/> optimize the design features of the bi-directional flow tube which can be applied for the various experimental<br/> conditions. 2-dimensional axisymmetric steady state flow analyses have been performed. By calculating the<br/> differential pressure at both the front and the rear hole of the flow tube, K values were evaluated. The K<br/> values show good linearity regardless of the tube sizes and the Re numbers in both water and air flow. And<br/> system pressure and water subcooling didn’t affect the K values. Under the elevated pressure of 80bar with<br/> 80K water subcooling, the K value indicates a similar trend with the case of 2bar with 80K water subcooling.
단상 및 이상유동 유량 계측을 위한 평균 양방향 유동 튜브 개발
윤병조(Byong-Jo Yun),강경호(Kyong-Ho Kang),어동진(Dong-Jin Euh),백원필(Won-Pil Baek) 한국유체기계학회 2004 유체기계 연구개발 발표회 논문집 Vol.- No.-
Average Bi-directional flow tube was suggested to measure single and two phase flow rate. Its working principle is similar with Pitot tube, however, it makes it possible to eliminate the cooling system which is normally needed to prevent from flashing in the pressure impulse line of Pitot tube when it is used in the depressurization condition. The suggested instrumentation was tested in the air-water vertical test section which has 80㎜ inner diameter and 10m length. The flow tube was installed at 120 of L/D from inlet of test section. From the test, single air and water flow rate was measured successfully. For the emasurement of two phase flow rate, Chexal drift-flux correlation was used. In the test a new correlation of momentum exchange factor was suggested. The test result shows that the suggested instrumentation using the measured void fraction and Chexal drift-flux correlation can predict the mass flow rates within 10% error of measured data.
강경호(Kyoung-Ho Kang),윤병조(Byung-Jo Yun),어동진(Dong-Jun Euh),백원필(Won-Pil Baek),유선봉(Sun-Bong Yu) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
An advanced flow meter applicable to large diameter piping system was developed using the average BDFT(Bidirectional Flow Tube). This flow meter can be used to measure the flow rate of discharged gas having fine floating particles in the stack of the chemical reactor and the large-sized boiler. Also it can be applied to the large-sized industrial piping system having flow of oil without structural instability. As a first step of commercialization, we designed and manufactured the flow meters which are applicable to piping system having diameter of 200㎜ and 500㎜. The calibration test results indicated that this flow meter has linaerity within 0.5% in the Re number range of above 10,000 where is meaningful in terms of application.
파단 열림시간과 면적에 따른 동하중 변화에 대한 민감도연구
강경호(Kyoung-Ho Kang),박현식(Hyun-Sik Park),조석(Seok Cho),최남현(Nam-Hyun Choi),배성원(Sung-Won Bae),이승욱(Seung-Wook Lee),김연식(Yeon-Sik Kim),최기용(Ki-Yong Choi),백원필(Won-Pil Baek) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
Integral effect tests using the ATLAS facility were performed to investigate the blowdown load behavior during a feedwater line break accident of a steam generator. As a sensitivity study, the break opening time and the break area were varied in the tests. After the break of the feedwater line, propagation of the pressure wave along the distance from the break location inside the steam generator was clearly and pertinently observed in all the tests. As the break opening time became shorter and the broken area became larger, the dynamic pressures were measured to be significant values in the tests. Based on the present experimental data, an analysis was performed using the best-estimate thermal-hydraulic system code, MARS 3.1 with an aim of qualitatively validating the test results and also evaluating the blowdown load prediction capability of the best-estimate system code in the simulation of steam generator feedwater line break. Calculation results on overall trends of the dynamic pressure behavior were comparable with the test results which indicated a feasibility of dynamic load prediction using the MARS code.
Bubble Sizing of Two-Phase Flow using A-B-Polar Scan Mode by Ultrasonic Reflection Coefficients
Kil-Mo KOO(구길모),In-Cheol Chu(주인철),Nam-Hyun Choi(최남현),Chul-Hwa SONG(송철화),Won-Pil BAEK(백원필) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
In this paper, a preliminary examination for a bubble sizing technique shows that a bubble of a two-phase flow can be measured by a quantitative method using patterns of an ultrasonic reflection coefficient on a single channel mode between parameters of an ultrasonic transducer and reflection coefficients of a bubble shape. In that experiment, we also have established a PC-based UT special mode system through analysis of ultrasonic measurement principles and a basic reflection theory for a bubble sizing which can be shown A-BPolar scan mode. This system will be used to study the applications of ultrasonic semi-tomographic techniques having 8 channels as a robust non-invasive tool for direct analysis of the characteristics of multiphase flows.