• Title/Summary/Keyword: Whirl Natural

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Effects of Design Conditions in Five Pad Tilting Pad Bearing on the Lateral Vibration Characteristics of Small Gas Turbine (5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향)

  • Ha, Jin-Woong;Myung, Ji-Ho;Suk, Jhin-Ik;Lee, An-Sung;Kim, Young-Cheol
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.8
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    • pp.752-760
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    • 2011
  • In tilting pad bearing design process, the selection of the proper configuration type of either a load-between-pad(LBP) or load-on-pad(LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a five pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5 MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by its asymmetric dynamic properties.

Effects of Design Conditions in Five Pad Tilting Pad Bearing on the Lateral Vibration Characteristics of Small Gas Turbine (5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향)

  • Ha, Jin-Woong;Myung, Ji-Ho;Suk, Jhin-Ik;Lee, An-Sung;Kim, Young-Cheol
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.04a
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    • pp.425-432
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    • 2011
  • In tilting pad bearing design process, the selection of the proper configuration type of either a Load-Between-Pad (LBP) or Load-On-Pad (LOP) as well as preload and pivot offset conditions is to be carefully considered. Also the bearing needs to be designed in order to be suited for the rotor-bearing system and operating condition. In this paper, it is observed that the dynamic characteristics in a 5 pad tilting pad bearing for the LBP and the LOP configurations are influenced by the variation of preload and pivot offset. In this context, rotor dynamic analysis of the 5MW industrial gas turbine supported by the tilting pad bearing at the front and roller bearing at the rear is carried out based on the dynamic coefficients of the tilting pad bearing investigated. The result shows that two rigid body critical modes experience various changes according to the influence of the tilting pad bearing uniquely applied to one side of this machine. Mainly, the second critical speed, the rigid body mode of conical shape with high whirling in the tilting pad bearing, is significantly changed by preload and pivot offset regardless of the LBP and LOP configurations. And, the first critical mode, the rigid body mode of conical shape with high whirling in the roller bearing, is sensitively affected by preload applied to the LOP configuration and by the its asymmetric dynamic properties.

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A Study on Housing Problem of The Yi-Dynasty - With a Focus on The House - plan - Analysis of Upper - class - (이조시대의 주생활에 관한 소고 - 상류주택의 평면분석을 중심으로 -)

  • 이인희
    • Journal of the Korean Home Economics Association
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    • v.11 no.1
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    • pp.3-13
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    • 1973
  • This article has an aim to study what kind of housing system our ancestors lived with during the Yi-Dynasty by analyzing the house-plan of upper-class society of that period since the house of lower-class was very insignificant as it has always been while the house of upper-class represented the period. With this study we can clearly see how we ought to go in the right direction toward the development of our Korean genuine housing by renovating and renewing those unreasonable points in our traditional housing system. It is firmly believed that we should-keep our own unique traditional lovely housing system for being destroyed by the whirl-wind of modernization and the demand of rationalism and efficiency-centered idea of the western mind. From this view point we think it is very urgent to see this matter correctly and find out the real way how we should do in order to keep our own good things for ourselves and make them preserved. This essay is divided into three parts as follows : 1. Thoughts on selecting the good housing area. 2. The aspect of housing reflected upon composing the house-plan. 3. The characteristic sentiments reflected upon the interior construction and decoration. We can find several characteristic points in the housing system of the Yi-Dynasty as follows : 1. In Korea, the thought of natural geography (Poongsu-seul), apart fro scientific view, which seems rather superstitious to us, modern young people, has been highly recommended by the people of our country from old days connected with the prosperity of our life. They also neglected about the social circumstances such as, market, transportation, and education, which are now considered as very important. They only put their concern on this natural environment which they called Poongsu. 2. In construction of house-plan, the house was not built for living with reasonable convenience, but for showing prestige of the upper-class people reflecting its social organization under the feudalism of the period. Furthermore, the most of the housework was done actually by those servants and maids of the house, and not the family themselves. The only concern for the upper-class people was to show off their authority, and so this sense of authority was revealed in the housing as well. 3. Both the outside appearance of the house and the interior decoration or the furniture are all very artistic and lovely. They were so refined and beautiful with their delicate taste which truly seem against our modern rationalism and uniformity.

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