Rotor Dynamic Analysis for a Shaft Train by Using Finite Element Method

Authors: M. Najafi

Abstract:

In the present paper, a large turbo-generator shaft train including a heavy-duty gas turbine engine, a coupling, and a generator is established. The method of analysis is based on finite element simplified model for lateral and torsional vibration calculation. The basic elements of rotor are the shafts and the disks which are represented as circular cross section flexible beams and rigid body elements, respectively. For more accurate results, the gyroscopic effect and bearing dynamics coefficients and function of rotation are taken into account, and for the influence of shear effect, rotor has been modeled in the form of Timoshenko beam. Lateral critical speeds, critical speed map, damped mode shapes, Campbell diagram, zones of instability, amplitudes, phase angles response due to synchronous forces of excitation and amplification factor are calculated. Also, in the present paper, the effect of imbalanced rotor and effects of changing in internal force and temperature are studied.

Keywords: Rotor dynamic analysis, Finite element method, shaft train, Campbell diagram.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3607848

References:

[1] Y. Ishida, T. Yamamoto, Linear and Nonlinear Rotordynamic: A modern treatment with applications, Wiley, New York, 2012.
[2] Michel Lalanne & Guy Ferraris, Rotordymanics Prediction in Engineering, 2nd ed. John Wieey and Sons.
[3] L. Meirovitch, Fundamentals of Vibrations, McGraw Hill, New York, 2001.
[4] G. Genta, Dynamics of Rotating Systems, springer, New York, 2005.
[5] Duncan Walker. Torsional Vibration of Turbo machinery, McGraw-hill.
[6] Agnieszka Muszynska, Rotor dynamics, Taylor & Francis Group.
[7] T. Someya, Joumal Bearing Data book, Springer-Verlag.
[8] API 684, Tutorial on the API Standard Paragraphs Covering Rotor Dynamics and Balancing
[9] M Najafi, S Bab, F. Rahimi Dehgolan, Super Harmonic Nonlinear Lateral Vibration of an Axially Moving Beam with Rotating Prismatic Joint, World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering Vol:11, No:4, 2017.
[10] F. Rahimi Dehgolan, SE Khadem, S Bab, M Najafi, Linear Dynamic Stability Analysis of a Continuous Rotor-Disk-Blades System, World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 12 (4) (2016) 349–357.