피봇 강성을 고려한 틸팅 패드 저널 베어링의 해석
Analysis of Tilting Pad Journal Bearings Considering Pivot Stiffness
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초록
This study set out to predict the load capacity and rotordynamic coefficients of tilting-pad journalbearings, taking the pivot stiffness into account. The analysis uses rocker-back (cylindrical) and ball in socket(spherical) pivot models, both of which are based on Hertzian contact stress theory. The models ascertain thenon-linear elastic deformation of the pivots according to the applied load, pivot geometry, and material properties. At present, the Reynolds equation for an isothermal, isoviscous, and incompressible fluid is used to calculatethe film pressure by using the finite-element method, after which the Newton–Raphson method is usedto simultaneously find the journal center location, pad angles, and pivot deflections. The bearing analysis, excludingthe pivot models, is validated using predictions those are readily available in the literature. As the rotor speedincreases, the predicted journal eccentricity and damping coefficients decrease, but the stiffness coefficientsincrease, as expected. Most importantly, the implementation of the pivot models increases the journal eccentricitybut significantly decreases the stiffness and damping coefficients of the tilting-pad journal bearings.
Abstract
This study set out to predict the load capacity and rotordynamic coefficients of tilting-pad journalbearings, taking the pivot stiffness into account. The analysis uses rocker-back (cylindrical) and ball in socket(spherical) pivot models, both of which are based on Hertzian contact stress theory. The models ascertain thenon-linear elastic deformation of the pivots according to the applied load, pivot geometry, and material properties. At present, the Reynolds equation for an isothermal, isoviscous, and incompressible fluid is used to calculatethe film pressure by using the finite-element method, after which the Newton–Raphson method is usedto simultaneously find the journal center location, pad angles, and pivot deflections. The bearing analysis, excludingthe pivot models, is validated using predictions those are readily available in the literature. As the rotor speedincreases, the predicted journal eccentricity and damping coefficients decrease, but the stiffness coefficientsincrease, as expected. Most importantly, the implementation of the pivot models increases the journal eccentricitybut significantly decreases the stiffness and damping coefficients of the tilting-pad journal bearings.
참고문헌 (15)
- Kim, J. S, "Inlet Pressure Effects on the Static and Dynamic Characteristics of Tilting-Pad Journal Bearings", JSME Int. J. Ser, 35, pp.121~127 (1992)
- Ha, H. C, "Dynamic Analysis of a Large Tilting Pad Journal Bearing Including the Effects of Temperature Rise and Turbulence", Trans. Korean Soc.Mech. Eng, 19(2), pp.313~321 (1995)
- 김성기, "패드 수의 변화가 대형 틸팅패드 저어널 베어링의 정특성에 미치는 영향", 한국윤활학회지, 20(6), pp.330~336 (2004), 한국윤활학회
- Ha, J. W, "Effect of Preload in a Tilting Pad Bearing of Load-Between - Pad and Load-On-Pad Configurations on the Lateral Vibration Characteristics of Small Gas Turbine", Proc. KMFA, pp.131~137 (2010)
- 하진웅, "5패드 틸팅 패드 베어링의 설계 조건 변화가 소형 가스터빈의 횡진동 특성에 미치는 영향", 한국소음진동공학회논문집, 21(8), pp.752~760 (2011), 한국소음진동공학회
- Nicholas, J. C, "Stiffness and Damping Coefficients for the Five Pad Tilting Pad Bearing", ASLE Trans, 22(2), pp.112~124 (1979)
- Kirk, R. G, "Evaluation of Pivot Stiffness for Typical Tilting-Pad Journal Bearing Designs", ASME J. Vib. Acoust, Stress and Reliab, 110(2), pp.165~171 (1988)
- Nicholas, J. C, "Tilting Pad Journal Bearing Pivot Design for High Load Applications", Proc. 24th Turbomachinery Symposium, Turbomachinery Laboratory, pp.33~47 (1995), Texas A&M University, College Station, TX
- San Andres, L, "Hybrid Flexure Pivot-Tilting Pad Gas Bearings: Analysis and Experimental Validation", ASME J. Tribol, 128, pp.551~558 (2006)
- Childs, D, "Static Performance Characteristics and Rotordynamic Coefficients for a Four-Pad Ball-in-Socket Tilting Pad Journal Bearing", ASME J. Eng. Gas Turbines Power, 131, pp.062502~ (2009)
- Young, W. C, "Roark’s Formulas for Stress and Strain" (2001), McGraw-Hill
- Balbahadur, A. C, "A Theromelastohydrodynamic Model of The Morton Effent Operation in Overhung Rotors Supported by Plain or Tilting Pad Journal Bearings", 박사, Mechanical Engineering, pp.2001
- Monmousseau, P, "Transient Thermoelastohydrodynamic Study of Tilting Pad Journal Bearings – Comparison between Experimental Data and Theoretical Results", ASME J. Tribol, 119, pp.401~407 (1997)
- Reddy, J. N, "An Introduction to the Finite Element Method" (1993), McGRAW-HILL
- Someya, T, "Journal-Bearing Databook", pp.11146~1148 (1989), Springer-Verlag