• Title/Summary/Keyword: whirling process

Search Result 13, Processing Time 0.018 seconds

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
    • /
    • 2011.04a
    • /
    • pp.425-432
    • /
    • 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.

  • PDF

Finite Element Formulations of the Rotor-Bearing System for Whirl Speed Analysis (로터-베어링 시스템의 훨링속도 해석을 위한 유한요소 정식화)

  • Yun, Seong-Ho
    • Proceedings of the Computational Structural Engineering Institute Conference
    • /
    • 2007.04a
    • /
    • pp.625-630
    • /
    • 2007
  • This paper accounts for derivations and formulations of the finite element dynamic equation of the rotor-bearing system to analyze its whirling speed. It turns out to be a different form from previous researcher's because of different successive sequences of Euler angles. Correspondingly the adoption of other rotation tensor will be needed for a consistent derivation of the dynamic equation. The process of its finite element formulation with consistent mass matrix and gyroscopic matrix involves a general definition of the modal analysis or the Eigen analysis for the damped system in the inertial frame and rotating frame, respectively.

  • PDF

Decision Making Experience on Breast Reconstruction for Women with Breast Cancer (한국 유방암 여성들의 유방재건술에 관한 의사결정 경험)

  • Yi, Myungsun;Joung, Woo Joung;Park, Eun Young;Kwon, Eun Jin;Kim, Haejin;Seo, Ji Young
    • Journal of Korean Academy of Nursing
    • /
    • v.46 no.6
    • /
    • pp.894-904
    • /
    • 2016
  • Purpose: The purpose of this study was to explore decision making experiences of Korean women with breast cancer who underwent breast reconstruction with/after a mastectomy. Methods: Data were collected during 2015-2016 through individual in-depth interviews with 10 women who had both mastectomy and breast reconstruction, and analyzed using phenomenological method to identify essential themes on experiences of making a decision to have breast reconstruction. Results: Five theme clusters emerged. First, "expected loss of sexuality and discovery of autonomy" illustrates various aims of breast reconstruction. Second, "holding tight to the reputation of doctors amid uncertainty" specifies the importance of a trust relationship with their physician despite a lack of information. Third, "family members to step back in position" describes support or opposition from family members in the decision making process. Fourth, "bewilderment due to the paradox of appearance-oriented views" illustrates paradoxical environment, resulting in confusion and anger. Lastly, "decision to be made quickly with limited time to oneself" describes the crazy whirling process of decision making. Conclusion: Findings highlight aims, worries, barriers, and facilitators that women with breast cancer experience when making a decision about breast reconstruction. Deciding on breast reconstruction was not only a burden for women in a state of shock with a diagnosis of breast cancer, but also an opportunity to decide to integrate their body, femininity, and self which might be wounded from a mastectomy. These findings will help oncology professionals provide effective educational counselling before the operation to promote higher satisfaction after the operation.