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발전소 복수 공급 배관계의 고진동과 분기 배기배관의 절손 규명
김연환(Yeon-Whan Kim) 한국소음진동공학회 2010 한국소음진동공학회 학술대회논문집 Vol.2010 No.10
A disturbance flow at piping bands and discontinuous regions such as a valve, a header has a intense broadband internal pressure field and a sound field which are propagated through the piping system The fields becomes the source of a vibration of this piping system. Intense broadband disturbance flow at a discontinuous region such as elbows, valves or headers generates an acoustical pulsation. The pulsation becomes the source of structural vibration at the piping system. If it coincides with the natural frequency of the pipe system, excessive vibration results. High-level vibration due to the pressure pulsation affects the reliability of the plant piping system. This paper discusses the high vibration and the branch vent pipes failure of condensate-water supply piping system due to the effect of acoustical pulsations by flow turbulence from the flow control valves of globe type in a power site.
발전소 대형 수배관계의 충격성 이상 과도진동의 특성 고찰 사례
김연환(Yeon-Whan Kim),양경현(Gyeong-Hyeon Yang),배시연(Si-Yeon Bae),조종현(Jong-Hyeon Jo),Jae-Myeong Yu 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10
Leak problem with large pressure drop occurrs non-periodic shock pulsation due to the deterioration of a isolation valve in feed-water recirculation piping system. This paper discusses on the shock vibration and noise occurred due to the effect of acoustical shock pulsations by degradation of the isolation valve in a power site.
김연환(Kim, Yeon-Whan),김계연(Kim, Kye-Yean),배춘희(Bae, Chun-Hee),이영신(Lee, Young-Shin) 한국소음진동공학회 2008 한국소음진동공학회 논문집 Vol.18 No.9
This paper presents a case history on failures of impeller and shaft due to pressure pulsation at single stage feed water pumps in 700 MW nuclear power plant during commissioning operation. The pumps had been service and had run for approximately $40{\sim}50$ hours. For the most part, the failures of impeller occurred with the presence of a number of fatigue cracks. All cracks were associated with the deleterious surface layer of impeller by visual and metallurgical examination. On-site testing and analytical approach was performed on the systems to diagnose the problem and develop a solution to reduce the effect of exciting sources. A major concern at high-energy centrifugal pump is the pressure pulsation created from trailing edge of the Impeller blade, flow separation and recirculation at centrifugal pumps of partial load. Pressure pulsation due to the interaction generating between impeller and casing coincided with natural frequencies of the impeller and shaft system during 1ow load operation. It was identified that dynamic stress exceeding the fatigue strength of the material at the thin shroud section due to the hydraulic instability at running condition below BEP.