Research Papers: Gas Turbines: Structures and Dynamics

Dynamics of Slant Cracked Rotor for a Steam Turbine Generator System

[+] Author and Article Information
Chao Liu

State Key Laboratory of Control and Simulation
of Power System and Generation Equipments,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: chaoliu08@gmail.com

Dongxiang Jiang

State Key Laboratory of Control and Simulation
of Power System and Generation Equipments,
Department of Thermal Engineering,
Tsinghua University,
Beijing 100084, China
e-mail: jiangdx@tsinghua.edu.cn

1Corresponding author.

Contributed by the Structures and Dynamics Committee of ASME for publication in the JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER. Manuscript received December 9, 2015; final manuscript received September 26, 2016; published online January 24, 2017. Assoc. Editor: Rakesh K. Bhargava.

J. Eng. Gas Turbines Power 139(6), 062502 (Jan 24, 2017) (7 pages) Paper No: GTP-15-1565; doi: 10.1115/1.4035323 History: Received December 09, 2015; Revised September 26, 2016

Root causes of several recent crack failures in turbine units are attributed to oscillation and interaction between generator of turbine unit and devices on the grid, where torsional vibration of the rotor bearing system is observed and identified as an important cause. Exploring vibrational (lateral, torsional, and axial) features in the cracked rotor system with torsional excitation (TE) present can provide a novel view in crack detection and isolation. This work presents dynamic analysis of a cracked rotor system in a steam turbine unit (a typical rotor system with multiple rotors, multiple supports, and oscillating loads), and the vibrational features of the cracked rotor system with comparisons to typical features in monitored vibration data. The results show that coupled vibration in both lateral and torsional components is an effective indicator for cracks in the presence of torsional excitation. Also, vibration characteristics evaluated in different locations of the rotor system are beneficial for fault detection and isolation.

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Andrier, B. , Garbay, E. , Hasnaoui, F. , Massin, P. , and Verrier, P. , 2006, “ Investigation of Helix-Shaped and Transverse Crack Propagation in Rotor Shafts Based on Disk Shrunk Technology,” Nucl. Eng. Des., 236(4), pp. 333–349. [CrossRef]
Bachschmid, N. , Pennacchi, P. , Tanzi, E. , Verrier, P. , Hasnaoui, F. , and Aabadi, K. , 2004, “ Crack Detectability in Vertical Axis Cooling Pumps During Operation,” Int. J. Rotating Mach., 10(2), pp. 121–133. [CrossRef]
Rosario, D. A. , and Khalid, T. , 2005, “ Generator Shaft Keyway Cracking Failure Investigation,” 9th EPRI Steam Turbine/Generator Workshop, Denver, CO, Aug. 22–24, pp. 1–10.
Xie, X. , Liu, P. , Bai, K. , and Han, Y. , 2013, “ Applying Improved Blocking Filters to the SSR Problem of the Tuoketuo Power System,” IEEE Trans. Power Delivery, 28(1), pp. 227–235. [CrossRef]
Jiang, D. , Hong, L. , Wang, Z. , and Xie, X. , 2009, “ Torsional Vibration Analysis and Stress Calculation for the Fault 600 mw Steam Turbine Generator Shaft System,” ASME Paper No. DETC2009-86854.
Liu, C. , Jiang, D. , and Chen, J. , 2014, “ Coupled Torsional Vibration and Fatigue Damage of Turbine Generator Due to Grid Disturbance,” ASME J. Eng. Gas Turbines Power, 136(6), p. 062501. [CrossRef]
Xie, X. , Guo, X. , and Han, Y. , 2011, “ Mitigation of Multimodal SSR Using SEDC in the Shangdu Series-Compensated Power System,” IEEE Trans. Power Syst., 26(1), pp. 384–391. [CrossRef]
Lebold, M. S. , Maynard, K. P. , Trethewey, M. W. , Bieryla, D. J. , Lissenden, C. J. , Tissot, S. P. , Verrier, P. , and Metz, J. , 2003, “ Technology Development for Shaft Crack Detection in Rotating Equipment,” EPRI International Maintenance Conference, Chicago, IL, Aug. 18–20, pp. 1–12. http://php.scripts.psu.edu/staff/k/p/kpm128/pubs/EPRI-InternationalMaintenanceConf2003-Final_2.pdf
Szász, G. , and Guindon, E. J. , 2003, “ Using Torsional Vibration Spectra to Monitor Machinery Rotor Integrity,” ASME Paper No. IJPGC2003-40162.
Sawicki, J. T. , Friswell, M. I. , Kulesza, Z. , Wroblewski, A. , and Lekki, J. D. , 2011, “ Detecting Cracked Rotors Using Auxiliary Harmonic Excitation,” J. Sound Vib., 330(7), pp. 1365–1381. [CrossRef]
Papadopoulos, C. A. , 2008, “ The Strain Energy Release Approach for Modeling Cracks in Rotors: A State of the Art Review,” Mech. Syst. Signal Process., 22(4), pp. 763–789. [CrossRef]
Ichimonji, M. , Kazao, Y. , Watanabe, S. , and Nonaka, S. , 1994, “ The Dynamics of a Rotor System With a Slant Crack Under Torsional Vibration,” 1994 International Mechanical Engineering Congress and Exposition, ASME Applied Mechanics Division-Publications-AMD, Chicago, IL, Vol. 192, pp. 81–90.
Ichimonji, M. , and Watanabe, S. , 1988, “ The Dynamics of a Rotor System With a Shaft Having a Slant Crack: A Qualitative Analysis Using a Simple Rotor Model,” JSME Int. J., 31(4), pp. 712–718.
Sekhar, A. , and Prasad, P. B. , 1997, “ Dynamic Analysis of a Rotor System Considering a Slant Crack in the Shaft,” J. Sound Vib., 208(3), pp. 457–473. [CrossRef]
Sekhar, A. , Mohanty, A. , and Prabhakar, S. , 2005, “ Vibrations of Cracked Rotor System: Transverse Crack Versus Slant Crack,” J. Sound Vib., 279(3), pp. 1203–1217. [CrossRef]
Darpe, A. K. , 2007, “ Dynamics of a Jeffcott Rotor With Slant Crack,” J. Sound Vib., 303(1), pp. 1–28. [CrossRef]
Lin, Y. , and Chu, F. , 2009, “ Numerical and Experimental Investigations of Flexural Vibrations of a Rotor System With Transverse or Slant Crack,” J. Sound Vib., 324(1), pp. 107–125. [CrossRef]
Lin, Y. , Si, X. , and Chu, F. , 2011, “ Stability and Dynamics of Rotor System With 45 deg Slant Crack on Shaft,” Front. Mech. Eng., 6(2), pp. 203–213.
Darpe, A. , Gupta, K. , and Chawla, A. , 2004, “ Coupled Bending, Longitudinal and Torsional Vibrations of a Cracked Rotor,” J. Sound Vib., 269(1), pp. 33–60. [CrossRef]
Sinou, J.-J. , and Lees, A. , 2005, “ The Influence of Cracks in Rotating Shafts,” J. Sound Vib., 285(4), pp. 1015–1037. [CrossRef]
Darpe, A. K. , 2007, “ Coupled Vibrations of a Rotor With Slant Crack,” J. Sound Vib., 305(1), pp. 172–193. [CrossRef]
Wang, S. , Zi, Y. , Wan, Z. , Li, B. , and He, Z. , 2015, “ Effects of Multiple Cracks on the Forced Response of Centrifugal Impellers,” Mech. Syst. Signal Process., 60–61, pp. 326–343. [CrossRef]
Stoisser, C. M. , and Audebert, S. , 2008, “ A Comprehensive Theoretical, Numerical and Experimental Approach for Crack Detection in Power Plant Rotating Machinery,” Mech. Syst. Signal Process., 22(4), pp. 818–844. [CrossRef]
Liu, C. , Jiang, D. , Chen, J. , and Chen, J. , 2012, “ Torsional Vibration and Fatigue Evaluation in Repairing the Worn Shafting of the Steam Turbine,” Eng. Failure Anal., 26, pp. 1–11. [CrossRef]
Xie, X. , Zhang, C. , Liu, H. , Liu, C. , Jiang, D. , and Zhou, B. , 2016, “ Continuous-Mass-Model-Based Mechanical and Electrical Co-Simulation of SSR and Its Application to a Practical Shaft Failure Event,” IEEE Trans. Power Syst., 31(6), pp. 5172–5180. [CrossRef]
Liu, C. , and Jiang, D. , 2014, “ Crack Modeling of Rotating Blades With Cracked Hexahedral Finite Element Method,” Mech. Syst. Signal Process., 46(2), pp. 406–423. [CrossRef]
Liu, C. , Jiang, D. , and Chu, F. , 2015, “ Influence of Alternating Loads on Nonlinear Vibration Characteristics of Cracked Blade in Rotor System,” J. Sound Vib., 353, pp. 205–219. [CrossRef]
Saito, A. , Castanier, M. P. , and Pierre, C. , 2009, “ Effects of a Cracked Blade on Mistuned Turbine Engine Rotor Vibration,” ASME J. Vib. Acoust., 131(6), p. 061006. [CrossRef]
Saito, A. , Castanier, M. , and Pierre, C. , 2009, “ Estimation and Veering Analysis of Nonlinear Resonant Frequencies of Cracked Plates,” J. Sound Vib., 326(3), pp. 725–739. [CrossRef]
Liu, C. , and Jiang, D. , 2010, “ Fatigue Damage Evaluation of Turbine Generator Due to Multi-Mode Subsynchronous Oscillation,” ASME Paper No. DETC2010-28045.
IEEE Subsynchronous Resonance Working Group, 1992, “ Readers Guide to Subsynchronous Resonance-IEEE Committee Report,” IEEE Trans. Power Syst., 7(1), pp. 150–157. [CrossRef]
Chen, J. , Jiang, D. , and Liu, C. , 2013, “ Identification of Multi-Concurrent Fault in a Steam Turbine Rotor System Using Model-Based Method,” ASME Paper No. GT2013-94419.
Pennacchi, P. , Bachschmid, N. , and Vania, A. , 2006, “ A Model-Based Identification Method of Transverse Cracks in Rotating Shafts Suitable for Industrial Machines,” Mech. Syst. Signal Process., 20(8), pp. 2112–2147. [CrossRef]
Walker, D. , Bowler, C. , Jackson, R. , and Hodges, D. , 1975, “ Results of Subsynchronous Resonance Test at Mohave,” IEEE Trans. Power Appar. Syst., 94(5), pp. 1878–1889. [CrossRef]
Maljkovic, Z. , Stegic, M. , and Kuterovac, L. , 2010, “ Torsional Oscillations of the Turbine-Generator Due to Network Faults,” 14th International Conference on Power Electronics and Motion Control (EPE/PEMC), Ohrid, Macedonia, Sept. 6–8, pp. 82–85.
Kulesza, Z. , and Sawicki, J. T. , 2013, “ New Finite Element Modeling Approach of a Propagating Shaft Crack,” ASME J. Appl. Mech., 80(2), p. 021025. [CrossRef]
Sabnavis, G. , Kirk, R. , Kasarda, M. , and Quinn, D. , 2004, “ Cracked Shaft Detection and Diagnostics: A Literature Review,” Shock Vib. Dig., 36(4), p. 287. [CrossRef]
Pennacchi, P. , and Vania, A. , 2008, “ Diagnostics of a Crack in a Load Coupling of a Gas Turbine Using the Machine Model and the Analysis of the Shaft Vibrations,” Mech. Syst. Signal Process., 22(5), pp. 1157–1178. [CrossRef]


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Fig. 1

Model of slant crack in rotor. Crack area is marked as gray, with crack direction at 45 deg to the axial direction, and crack ratios as 0.2 and 0.4 (crack depth/diameter, 0.2 is shown here).

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Fig. 2

Profile of rotor bearing system in steam-turbine generator

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Fig. 3

Natural frequencies in torsional modes of normal and cracked rotor systems, obtained with finite element model

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Fig. 4

Modal shapes of torsional modes in the rotor bearing system, obtained with finite element model

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Fig. 5

Vibration in perpendicular direction close to bearing 7 with torsional excitation, obtained with finite element model. Ranges in y-axis are amplified to show the local sidebands. (a) Normal rotor system, (b) cracked rotor system (0.2), and (c) cracked rotor system (0.4).

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Fig. 6

Vibration collected in practical steam turbine unit (in perpendicular direction, from field data, TE—torsional excitation): (a) vibration (no TE), (b) vibration (TE), (c) spectrum (no TE), and (d) spectrum (TE)

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Fig. 7

Orbits of rotor system in normal and cracked conditions with torsional excitation (TE), obtained with finite element model: (a) normal, no TE, (b) normal, TE, (c) cracked 0.2, no TE, (d) cracked 0.2, TE, (e) cracked 0.4, no TE, and (f) cracked 0.4, TE

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Fig. 8

Orbits at bearing 7 in cracked rotor system of a steam turbine unit (from field data): (a) no torsional excitation and (b) with torsional excitation

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Fig. 9

Axial vibration of rotor system with torsional excitation, obtained with finite element model: (a) normal rotor and (b) cracked rotor (0.2)



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