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A Study on the Stem Coefficient of Friction of Motor- operated Gate/Globe halves
Jeoung, Rae-Hyuck,Park, Sung-Keun,Lee, Do-Hwan,Kim, Yang-Seok Korean Nuclear Society 2003 Nuclear Engineering and Technology Vol.35 No.2
Stem-stem nut coefficient of friction(COF) in motor-operated gate/globe valves is one of the important factors which determine the performance of the valve/actuators. The COF is affected greatly by the type and condition of the stem-stem nut lubricants, environmental parameters, surface condition of the stem/stem-nuts, and the number of strokes after the lubrication. In this paper, the measured data of the COFs at stem threads of some safety-related motor-operated gate/globe valves in domestic nuclear power plants are presented. In addition, the performance of the lubricants is evaluated by comparing the COFs among those valves. The results show that the measured COF at torque switch trip are higher than the unwedging COF and conservatively applicable to the unwedging COF. It is also shown that the lubricating performance based on the measured COFs varies with the lubricants.
정래혁 ( Rae Hyuck Jeoung ),이병곤 ( Byung Kon Lee ) 충북대학교 산업과학기술연구소 2012 산업과학기술연구 논문집 Vol.26 No.1
Mechanical seals are one of main components of high speed centrifugal pumps. So, it is very important to detect the faults of mechanical seals since the damage of seal can cause a critical failures of accidents of machinery system. In the past, many researchers mainly performed to detect the seal fault using the time signals measured from sensors. Recently, studies are focused on the development of on-line real time monitoring system. But sutyd on the feature perameters used fault detection of mechanical seals has a little been performed. In theis paper, we showed feature parameters extracted from accelerated and acoustic signals by using the discrete wavelet tansform, alpha coefficient, statistical parameters. And also verified the possibility for fault detection of mechanical seal.
정래혁 ( Rae Hyuck Jeoung ),이병곤 ( Byung Kon Lee ) 한국안전학회(구-한국산업안전학회) 2012 한국안전학회지 Vol.27 No.3
Mechanical seals are one of main components of high speed centrifugal pumps. So, it is very important to detect the faults (scratch, notch, indentation, wear) of mechanical seals since the damage of seal can cause a critical failures or accidents of machinery system. In the past, many researchers mainly performed to detect the seal fault using the time signals measured from sensors. Recently, studies are focused on the development of on-line real time monitoring system. But study on the feature parameters used for fault detection of mechanical seals has a little been performed. In this paper, we showed feature parameters extracted from accelerated and acoustic signals by using the discrete wavelet transform (DWT), alpha coefficient, statistical parameters. And also verified the possibility for fault detection of mechanical seal
모터구동 글로브밸브의 Side Flow에 의한 디스크 - 몸체 마찰부하 평가
정래혁(Rae-Hyuck Jeoung),박성근(Sung-Keun Park),이도환(Do-Hwan Lee),송석윤(Seok-Yoon Song),강신철(Shin-Cheul Kang) 한국유체기계학회 2003 유체기계 연구개발 발표회 논문집 Vol.- No.-
EPRI PPM (Performance Prediction Methodology), a method used for the prediction of required thrust of valves, can not be applied to unbalanced-disk globe valves operated in the fluid when the fluid temperature is above 150˚F because the thrust increase caused by the friction between the valve disk and body is not considered in the PPM. In order to apply PPM to the valves, EPRI suggested new friction prediction method to be added in the code. This paper analyzes the applicability of the prediction method comparing the disk-to-body friction load predicted from the method with the measured friction load from the field tests. The maximum values from the prediction method and those obtained from the test were 268lbs and about 1500lbs, respectively. It is included that the prediction method should be improved for the realistic prediction of disk-to-body friction load.
원전 회전기기의 지능형 결함 진단을 위한 Z-SCORE법 기반의 특징 파라미터 추출
정래혁,이병곤,Jeoung. Rae Hyuck,Lee. Byung Kon 한국방재학회 2012 한국방재학회논문집 Vol.12 No.3
최근 산업 발전에 따라 회전기기에 대한 수요 증가와 더불어 사고 발생률도 크게 높아졌으며, 이들 문제에 대한 해결 방안으로 지능형 결함 진단이 대두되었다. 이에 본 논문에서는 회전기기 부품들 중 손상 발생 빈도수가 높은 회전체를 대상으로 진단 알고리즘에 입력되는 특징 파라미터들을 제시하였다. 이를 위해서, 원자력발전소의 펌프 고장 이력 자료로부터 대표적 결함 유형 9가지를 선정하였고, 현장 신호 확보의 어려움으로 모사 실험을 수행하였다. 특징적인 결함 신호 패턴을 정량화시키기 위해 가속도 신호로부터 총 84개의 통계 파라미터를 계산하였고, Z-SCORE법을 이용하여 통계 파라미터들 각각의 결함 식별 능력을 평가하였다. 그리고 서포트벡터머신을 이용한 결함 분류 상태 확인을 통해 RAW-P7, RAW-P8, RAW-P4, WT2-NNL, WT2-EE 파라미터들이 회전체 진단에 우수한 특징 파라미터임을 제안하였다. Recently, uses of rotating machinery have been increased sharply and failure occurrence also was significantly increased along with the industrial development. To solve these problems, intelligent fault diagnosis was tried. In this paper, feature parameters for the rotor with high frequency of failure occurrence, which are used as algorithm input, were suggested. To do this, 9 fault types from pump historical failure data of nuclear power plants were selected and simulation testing was performed. Total 84 statistical parameters were calculated to quantify fault signal pattern from the acceleration signal and fault discrimination capability for each parameter was evaluated by using the Z-SCORE method. Finally, RAW-P7, RAW-P8, RAW-P4, WT2-NNL, WT2-EE through verification of fault classification status using the SVM were proposed as the superior parameters for intelligent fault diagnosis of rotor.
모터구동 게이트밸브 열림행정시 차압 작용에 의한 부하율 연구
김대웅(Dae Woong Kim),박성근(Sung Keun Park),정래혁(Rae Hyuck Jeoung),이도환(Do Hwan Lee),홍승열(Sung Yull Hong) 한국유체기계학회 2004 유체기계 연구개발 발표회 논문집 Vol.- No.-
The Rate-of-Loading(ROL) effect of motor operated gate valves causes a decrease in the thrust delivered at a specific torque by the actuator under dynamic flow △P conditions as compared to the no-flow, static conditions. This effect needs to be studied for the quantitative evaluation of motor operated gate valve operability. This study is performed to verify the validity for the application of ROL in the evaluation of operability of motor operated gate valves for the opening stroke. The ROL is assessed on the basis of in-situ test data for the opening and closing strokes. The results show that the distribution of the ROL for the opening stroke has a tendency to the negative value when DP is higher than 150psid.
원자로 냉각재 펌프 고장예측진단을 위한데이터 분석 플랫폼 구축
김주식(Ju Sik Kim),조성한(Sung Han Jo),정래혁(Rae Hyuck Jeoung),조은주(Eun Ju Cho),나영균(Young Kyun Na),유기현(Ki Hyun You) 한국IT서비스학회 2021 한국IT서비스학회지 Vol.20 No.3
Reactor Coolant Pump (RCP) is core part of nuclear power plant to provide the forced circulation of reactor coolant for the removal of core heat. Properly monitoring vibration of RCP is a key activity of a successful predictive maintenance and can lead to a decrease in failure, optimization of machine performance, and a reduction of repair and maintenance costs. Here, we developed real-time RCP Vibration Analysis System (VAS) that web based platform using NoSQL DB (Mongo DB) to handle vibration data of RCP. In this paper, we explain how to implement digital signal process of vibration data from time domain to frequency domain using Fast Fourier transform and how to design NoSQL DB structure, how to implement web service using Java spring framework, JavaScript, High-Chart. We have implement various plot according to standard of the American Society of Mechanical Engineers (ASME) and it can show on web browser based on HTML 5. This data analysis platform shows a upgraded method to real-time analyze vibration data and easily uses without specialist. Furthermore to get better precision we have plan apply to additional machine learning technology.