패드 선단 테이퍼를 갖는 수력 수직 원통형 터빈 가이드 베어링의 성능향상 - 테이퍼 각도와 길이의 영향
Performance Improvement of Cylindrical Turbine Guide Bearings with Pad Leading-Edge Tapers for Vertical Hydro-Power Application: Effects of Taper Angle and Length
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Cylindrical turbine guide bearings (TGBs) with simple plain pads have conventionally been used in vertical hydro-power turbine-generator applications in order to provide turbine runner shafts with smooth rotation guides and supports. To overcome low-load/low-eccentricity performance drawbacks, such as very low film stiffness and lack of design credibility in the stiffness values themselves, of conventional cylindrical TGBs, the introduction of a rotational-directional leading-edge taper to each partitioned pad, simply pad leading-edge taper, has been found to be very effective in enhancing their design-application availability and usefulness. In this study, we investigate the effects of taper angle and length for given taper heights in detail in order to systematically establish the effectiveness of design on the performance improvement of vertical hydro-power application cylindrical TGBs with pad leading-edge tapers. The analysis results with 4-Pad×1-Row cylindrical TGBs show that the lubrication performance of the cylindrical TGBs is optimized with an approximate taper angle ratio of 0.8 and taper length ratio of 0.9. We conclude that the introduction of pad leading-edge tapers along with the optimization of taper designs can be very effective in improving the overall operation reliability of cylindrical TGBs and the rotordynamic characteristics of vertical hydro-power turbine-generator rotor-bearing systems as well, to which the TGBs are applied.
Abstract
Cylindrical turbine guide bearings (TGBs) with simple plain pads have conventionally been used in vertical hydro-power turbine-generator applications in order to provide turbine runner shafts with smooth rotation guides and supports. To overcome low-load/low-eccentricity performance drawbacks, such as very low film stiffness and lack of design credibility in the stiffness values themselves, of conventional cylindrical TGBs, the introduction of a rotational-directional leading-edge taper to each partitioned pad, simply pad leading-edge taper, has been found to be very effective in enhancing their design-application availability and usefulness. In this study, we investigate the effects of taper angle and length for given taper heights in detail in order to systematically establish the effectiveness of design on the performance improvement of vertical hydro-power application cylindrical TGBs with pad leading-edge tapers. The analysis results with 4-Pad×1-Row cylindrical TGBs show that the lubrication performance of the cylindrical TGBs is optimized with an approximate taper angle ratio of 0.8 and taper length ratio of 0.9. We conclude that the introduction of pad leading-edge tapers along with the optimization of taper designs can be very effective in improving the overall operation reliability of cylindrical TGBs and the rotordynamic characteristics of vertical hydro-power turbine-generator rotor-bearing systems as well, to which the TGBs are applied.
참고문헌 (5)
- A. S. Lee, "A Low-Load Performance Improvement Design for Cylindrical Turbine Guide Bearings in Hydro-Power Applications", Proceedings of the 7th International Symposium on Fluid Machinery and Fluids Engineering, ISFMFE 2016 (2016)
- R. Pai, "Modelling of Fluid Flow in a 3-Axial Groove Water Bearing using Computational Fluid Dynamics", Proceedings of the 14th Australasian Fluid Mechanics Conference, pp.331~334 (2001), Adelaide Univ.
- R. Pai, "Chapter 13 Water Lubricated Bearings", pp.347~391 (2012), Green Tribology, Spring-Verlag
- G. Gao, "Numerical Analysis of Plain Journal Bearing under Hydrodynamic Lubrication by Water", Tribology International, 75, pp.31~38 (2014)
- 이안성, "수력 원통형 터빈 가이드 베어링의 저부하", 저편심 성능향상 설계 – 패드 선단 테이퍼의 도입, 2017, pp.33(2), 65~70[DOI]