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카플란수차에서 발생하는 진동현상 연구

Vibration Analysis due to the Kaplan turbine.,

피인섭 (Phie, In Sub, 경상대학교 대학원 항공공학과)

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초록/요약moremore
Changing output of the power from 1000kW to 7000kW by 1000kW stages, We measured the vibration of Nam-gang hydropower by using a kaplan turbine of the vertical bulb type. In the range of measurement, we used a stay-vane part for the generator and set up the standardds of axiality and radius directi...
Changing output of the power from 1000kW to 7000kW by 1000kW stages, We measured the vibration of Nam-gang hydropower by using a kaplan turbine of the vertical bulb type. In the range of measurement, we used a stay-vane part for the generator and set up the standardds of axiality and radius direction of runner's casing part for the turbine by using an accelerometer. We measured 0~5kHz of frequency per 5minutes and performed vibrational tests, we realized that the cavitation phenomena caure vibrations as we raised the power in the analysis of the FFT. The value off the RMS means that not only the size of the vibrations but also possibilities of the cavitation's occurrence. Also it makes cavitation phenomena front and rear of 3.5kHz high -frequency range as the result. We measured the shape of runner to research into the cazitation,s effect accurately. After inspecting runner's surface accurately, we detected that cavities had been generated intensively from the upstream of the tuunner, grom the leading edge to the vicinity(20~60cm) inthe runner root Cavity which is genetated is 1/8~1/4 of dimension and is designed to getting incidence of angle of attack from aviewpoint of the runner character. Since there wasn't reasonable operations related tho the increased height of Nam-gang dam, the runner malfunctioned and after all it occurred the cavitation. It needs to decide output limit ranges according to changing water level. because the vibrations occurred in cavitation are differ from the water level. Also, it is required the shape of downstream gate, penstock, guide vane, runner to judge water flow conditions accurately. On the assumption that the water level of Nam-gang dam could be changed from the high water level to low water level for safety operation, there are 3 variables that Nam-gang hydropower can choose. 1. Adjusting method of guide vane's rotation angle 2. Adjusting method of runner vane's rotation angle 3. Adjusting method of water level of downstream It is required to carry out vibration tests with changing power at each water level in order to have a safety operation-maintenance. Also calculating water flow and judging cavitations according to three variables above are needed. As you can see in total vibration curves of each output of the power, operating below 6500KW was very recommended method to reduce vibrations and noises. Hereafter, the result which we obtained from status diagnosis is needed to present normal operating range. And it will be used as a reference design of the horizontal kaplan turbine.
목차moremore
ABSTRACT = vi
1. 서론 = 10
1.1 연구배경 및 목적 = 10
...
ABSTRACT = vi
1. 서론 = 10
1.1 연구배경 및 목적 = 10
1.2 연구내용 및 방법 = 11
2. 수력발전 일반 = 12
2.1 수력발전의 역사 = 12
2.2 수력발전의 개념 = 12
2.3 수력발전의 역할 변화 = 13
2.4 수력발전의 분류 = 15
2.5 국내 수력발전 현황 = 16
2.6 수력발전의 필요성 = 17
2.7 수차의 특징 = 18
2.8 카플란 수차의 기초이론 = 21
3. 수차 캐비테이션의 일반적 특징 = 28
3.1 수차 캐비테이션의 정의 = 28
3.2 캐비테이션 계수 = 29
3.3 카플란 수차에서 캐비테이션 발생 부위 = 31
3.4 캐비테이션의주요 원인 = 34
3.5 비속도 = 34
4. 진동신호 추출기법 = 37
4.1 시계열 신호의 통계적 처리 = 38
4.2 Fourier 변환과 파워 스펙트럼 = 38
4.3 주파수 스펙트럼의 통계적 처리 = 40
4.4 주파수 분석 = 42
5. 진동원인 분석 = 43
5.1 진동측정기를 이용하여 출력별 진동측정 = 43
5.2 Runner Blade 형상계측 = 61
5.3 Thoma의 Cavitation 계수를 이용한 이론해석 = 66
6. 결론 = 71
6.1 카플란 터빈의 운전중 발생하는 진동 분석 = 71
6.2 러너의 형상진단 = 72
6.3 안정적인 설비운영 방안 = 72
참고문헌 = 74
감사의 글 = 75