민감도 벡터를 이용한 스팀 터빈의 Morton Effect 발생 예측
Predicting the Morton Effect in a Steam Turbine withSensitivity Vector
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The Morton effect (ME) is an instability phenomenon occurring in rotating machineries supported by fluid film bearings and is induced by the thermal deformation of the overhung mass, which is a part of the rotating shaft. Herein, we describe the ME during the high-speed balancing test of a 20 MW class steam turbine. Additionally, to predict the rotating speed at which the ME occurs, we apply the sensitivity vector theory for the steam turbine. During the operation of the steam turbine, we observe a continuous increase in vibration and hysteresis near the rated speed, which is typical of the ME. Increasing the temperature of the lubricating oil supplied to the bearings from 40 to 60oC suppresses the occurrence of the ME. The rotordynamic analysis for the steam turbine suggests the existence of a mode in which the overhung mass undergoes significant deformation near the rated speed, and we presume that such a mode will increase the occurrence of the ME. The predicted rotating speed of ME occurrence, obtained through the sensitivity vector method, correlates with the test results. Moreover, increasing the temperature of the supplied lubricating oil mitigates the occurrence of ME by reducing the sensitivity between the temperature deviation vector and unbalance mass vector.
Abstract
The Morton effect (ME) is an instability phenomenon occurring in rotating machineries supported by fluid film bearings and is induced by the thermal deformation of the overhung mass, which is a part of the rotating shaft. Herein, we describe the ME during the high-speed balancing test of a 20 MW class steam turbine. Additionally, to predict the rotating speed at which the ME occurs, we apply the sensitivity vector theory for the steam turbine. During the operation of the steam turbine, we observe a continuous increase in vibration and hysteresis near the rated speed, which is typical of the ME. Increasing the temperature of the lubricating oil supplied to the bearings from 40 to 60oC suppresses the occurrence of the ME. The rotordynamic analysis for the steam turbine suggests the existence of a mode in which the overhung mass undergoes significant deformation near the rated speed, and we presume that such a mode will increase the occurrence of the ME. The predicted rotating speed of ME occurrence, obtained through the sensitivity vector method, correlates with the test results. Moreover, increasing the temperature of the supplied lubricating oil mitigates the occurrence of ME by reducing the sensitivity between the temperature deviation vector and unbalance mass vector.
참고문헌 (10)
- de Jongh, F. M., "The Synchronous Instability of a Compressor Rotor due to Bearing Journal Differential Heating", ASME J. Eng. Gas Turbines Power, 118(4), pp.816~824 (1996)[DOI]
- Keogh, P., "Journal Bearing Differential Heating Evaluation with Influence on Rotor Dynamic Behaviour", Proc. R. Soc. London, Ser.A, 441(1913), pp.527~548 (1993)
- Keogh, P. S., "The Dynamic Nature of Rotor Thermal Bending Due to Unsteady Lubricant Shearing Within a Bearing", Proc. R. Soc. London, Ser. A, 445, pp.273~290 (1994)[DOI]
- Balbahadur, A. C., "Part I-Theoretical Model for a Synchronous Thermal Instability Operating in Overhung Rotors", International Journal of Rotating Machinery, 10, pp.469~475 (2004)[DOI]
- Kirk, G., "Synchronous Thermal Instability Prediction for Overhung Rotors", 32nd Turbomachinery Symposium (2003)
- Schmied, J., "Hot Spots in Turboexpander Bearings: Case History, Stability Analysis, Measurements and Operational Experience", ASME Turbo Expo 2008, Berlin (2008)[DOI]
- Murphy, B., "Simplified Morton Effect Analysis for Synchronous Spiral Instability", ASME J. Vib. Acoust, 132(5), pp.051008~ (2010)[DOI]
- Lee, J., "Morton Effect Cyclic Vibration Amplitude Determination for Tilt Pad Bearing Supported Machinery", ASME J. Tribol, 135(1), pp.011701~ (2012)[DOI]
- Suh, J., "Three-Dimensional Thermohydrodynamic Morton Effect Simulation-Part I : Theoretical Model", ASME J. Tribol, 136(3), pp.031706~ (2014)[DOI]
- Yang, J., "Morton effect prediction with validation using a CFD based CNN for pad inlet temperatures", Mechanical Systems and Signal Processing, 185, pp.109827~ (2023)[DOI]