Abstract
Coupled turbine–generator rotor systems are unique in their vibration behavior compared to individual rotor systems. Changes in geometric and dynamic parameters of individual rotor systems and coupling affect the overall response. Since there is also bound to be inherent misalignment at the coupling location, along with residual unbalance in the system, the rotor response contains harmonics corresponding to both unbalance and misalignment. A coupled Jeffcott rotor system with central discs integrated with active magnetic bearing (AMB) is considered in this work. The mathematical model is formulated from four degrees of freedom coupled Jeffcott rotor systems using Lagrange’s equations. A SIMULINKTM model is created to generate vibration and current responses in the time domain. Secondly, a full-spectrum FFT analysis of the time-domain signal is performed to examine the harmonics of the rotor’s vibration response and AMB’s current response. The change in the nature of rotors’ response for various permutations of unbalance and angular misalignment is studied. The advantage of full spectrum over time-domain signals and orbit plots in diagnosing misalignment has been demonstrated.
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References
Ahmad AM, El-Shefai A (2006) Effect of misalignment on the characteristics of journal bearings. In: ASME turbo expo 2006: power for land, sea and air
Al-Hussain KM (2003) Dynamic stability of two rigid rotors connected by a flexible coupling with angular misalignment. J Sound Vib 266:217–234
Al-Hussain KM, Redmond I (2002) Dynamic response of two rotors connected by rigid mechanical coupling with parallel misalignment. J Sound Vib 249(3):483–498
Avendano RD, Childs DW (2012) One explanation for 2n response due to misalignment in rotors connected by flexible couplings. In: ASME turbo expo 2012, June 11–15, Denmark
Chacon JLF, Andicoberry EA, Kappatos V, Asfis G (2014) Shaft angular misalignment detection using acoustic emission. Appl Acoust 85:12–22
Gibbons CB (1976) Coupling misalignment forces. In: Fifth turbo machinery symposium. Gas Turbine Laboratories, Texas A&M University, pp 111–116
Hu W, Miah H, Feng NS, Hahn EJ (2000) A rig for testing lateral misalignment effects in a flexible rotor supported on three or more hydrodynamic journal bearings. Tribol Int 33:197–204
Jalan AK, Mohanty AR (2009) Model based fault diagnosis of a rotor-bearing system for misalignment and unbalance under steady state condition. J Sound Vib 327:604–622
Lee YS, Lee AW (1999) Modelling and vibration analysis of misaligned rotor-ball bearing systems. J Sound Vib 224(1):17–32
Lees AW (2007) Misalignment in rigidly coupled rotors. J Sound Vib 305:261–271
Ma L, Zhang J, Lin J, Wang J, Lu X (2015) Dynamic characteristics analysis of a misaligned rotor-bearing system with squeeze film dampers. J Zhejiang Univ Sci A (Appl Phys Eng) 1–17
Nikolajsen JL (1996) The effect of misalignment on rotor vibrations. In: International gas turbine and aero engine congress & exhibition, Birmingham
Patel TH, Darpe AK (2009) Experimental investigations on vibration response of misaligned rotors. Mech Syst Signal Process 23(7):2236–2252
Pennachhi P, Vania A, Chatterton S (2012) Nonlinear effects caused by coupling misalignment in rotors equipped with journal bearings. Mech Syst Signal Process 30:306–322
Prabhu BS (1997) An experimental investigation on the misalignment effects in journal bearings. Tribol Trans 40(2):235–242
Rao J, Sreenivas R, Chawla A (2001) Experimental investigation of misaligned rotors. In: ASME turbo expo, New Orleans
Rao AS, Sekhar AS (1996) Vibration analysis of rotor-coupling-bearing system with misaligned shafts. In: International gas turbine and aero engine congress & exhibition, Birmingham
Reddy MCS, Sekhar AS (2015) Detection and monitoring of coupling misalignment in rotors using torque measurements. Measurement 61:111–122
Rybczynski J (2011) The possibility of evaluating turbo-set bearing misalignment defects on the basis of bearing trajectory features. Mech Syst Signal Process 25:521–536
Sekhar AS, Prabhu BS (1995) Effects of coupling misalignment on vibrations of rotating machinery. J Sound Vib 185(4):655–671
Xu M, Marangoni RD (1994) Vibration analysis of a motor-flexible-coupling-rotor system subject to misalignment and unbalance, Part II: Experimental validation. J Sound Vib 176(5):681–691
Siva Srinivas R, Tiwari R, Kanna Babu Ch (2018) Application of active magnetic bearings in flexible rotordynamic systems—a state-of-the-art review. Mech Syst Signal Process 106:537–572
Kreyszig E (2011) Advanced engineering mathematics. Wiley
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Siva Srinivas, R., Tiwari, R., Kanna Babu, C. (2020). Some Numerical Studies on Coupled Turbine–Generator Rotor System Models. In: Dutta, S., Inan, E., Dwivedy, S. (eds) Advances in Rotor Dynamics, Control, and Structural Health Monitoring . Lecture Notes in Mechanical Engineering. Springer, Singapore. https://doi.org/10.1007/978-981-15-5693-7_3
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DOI: https://doi.org/10.1007/978-981-15-5693-7_3
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