SPECIALTY OF ROTOR’S DRIVE MECHANISM OSCILLATIONS
DOI:
https://doi.org/10.15802/stp2016/61032Keywords:
rotor, oscillations, actuator, characteristics, two-mass modelAbstract
Purpose. Scientific work is devoted to study the influence of dynamic coefficients of bearings segment (coefficients of resistance and recirculating power) on stability and subharmonics self-oscillating components of the rotor vibration in unstable region of rotational speeds. Methodology. The study is based on the methods: the theory of vibrations of mechanical systems with lumped parameters; Lagrange functions; linear algebra. Findings. The researchers made: a) justification of the discrete two-mass model of an unbalanced rotor, which takes into account the influence of rotation on dynamic coefficients; b) analysis and improvement of methods for engineering analysis of stability and parameter subharmonic self-oscillations in the unstable range of frequencies of rotation of the rotor; c) installation and classification of the main rotor causes of vibrations constructive or those arising in the manufacture, assembly and operation of the machine, and on the other hand, rotary systems specific for non-conservative forces, that lead under certain conditions to the self-oscillation; d) determination (identification) the characteristics/differences of rotor vibration, which lies in the fact that in most cases they are associated with the transverse vibrations of the rotors, while torsional or longitudinal oscillations play the incomparably smaller role, and therefore the last in this study were rejected; e)it is shown that the characteristic feature of the functioning of rotor systems of modern machines and units have no direct relationship with the level of vibration with amount of power that is transmitted through them or produced engine. Originality. In this paper the authors first considered the nonlinear response bearing lubrication layer, namely the coefficients of resistance and circulating forces that determine the dynamic coefficient of segment bearings. Practical value. The engineering calculations subharmonic stability and self-oscillations of the rotor (unbalanced) in unstable frequency of rotation are adjusted and significantly improved. The results of this work can be used to analyze rotary systems which under certain conditions can cause vibration that is not caused by some external periodic loads (or imperfections of the rotor) and the conditions of occurrence of which is not associated with some (any) resonant ratio (i.e., the system with self-excitation or self-oscillations). The latter are caused by the action of nonconservative forces of circulation type (circulation strength associated with the displacement vector of the rotor, not the velocity vector, as in systems with «negative» friction). As the circulating force vector is perpendicular to the vector displacement of the rotor, resulting in such a force can manifest themselves only in mechanical (rotary) systems with many degrees of freedom of movement greater than one. In addition, an important feature of the circulation of forces there should not be conservative, so the results can be used to study non-conservative rotor systems with asymmetric (skew-symmetric) matrix of coefficients.
References
Bondarenko I.O. Osoblyvosti protsesu rozpovsiudzhennia kolyvan pry deformatyvnii roboti zaliznychnoi kolii [Process features of fluctuations propagation at stress-strain work of the railway track]. Nauka ta prohres transportu – Science and Transport Progress, 2015, no. 5 (59), pp. 75-83. doi: 10.15802/stp2015/55336.
Chelomey V.N. Vibratsii v tekhnike [Vibrations in the technique]. Moscow, Mashinostroyeniye Publ., 1980. 544 p.
Gadyaka V.G., Leykikh D.V., Simonovskiy V.I. Matematicheskaya model rotora turbokompressora dlya isledovaniya nesinkhronnykh sostavlyayushchikh vibratsiy [A mathematical model for the study of the turbocharger rotor for asynchronous vibration components]. Kompressornoye i energeticheskoye mashinostroeniye – Compressor and Power Engineering, 2010, no. 2 (20), pp. 48-50.
Gadyaka V.G., Leykikh D.V., Simonovskiy V.I. Otsenivaniye vliyaniya nelineynykh reaktsiy segmentnykh podshipnikov na dinamiku i ustoychivost rotorov turbokompresorov [Evaluation of the influence of nonlinear reactions of segmental bearings on the dynamics and stability of turbochargers rotors]. Trudy mizhnarodnoi naukovo-tekhnichnoi konferentsii [Proc. of Intern. Sci. and Techn. Conf.]. Kyiv, 2011, pp.17-24.
Gadyaka V.G., Leykikh D.V., Simonovskiy V.I. Eksperimentalnoye issledovaniye dinamiki rotora v neustoychivoy oblasti chastot vrashcheniya [Experimental study of the dynamics of the rotor in the unstable region of rotational speeds]. Problemy mashinostroyeniya – Problems of Mechanical Engineering, 2009, vol. 12, no. 5, pp. 81-85.
Dimentberg F.M. Izgibnyye kolebaniya vrashchayushchikhsya valov [Flexural vibrations of rotating shafts]. Moscow, AN SSSR Publ., 1959. 340 p.
Iskovych-Lototskyi R.D., Ivanchuk I.V., Veselovskyi Ya.P. Osnovy rezonansno-strukturnoi teorii vibroudarnoho rozvantazhennia transportnykh zasobiv [The basis of resonance-structural theory of vibration shock unloading of the vehicle]. Nauka ta prohres transportu – Science and Transport Progress, 2014, no. 5 (53), pp. 109-118. doi: 10.15802/stp2014/30458.
Kelzon A.S., Zhuravlev Yu.N., Yanvarev N.V. Raschet i konstruirovaniye rotornykh mashin [Calculation and design of rotating machines]. Leningrad, Mashinostroyeniye Publ., 1977. 260 p.
Kushul I.Ya. Avtokolebaniya rotorov [Self-oscillations of the rotors]. Moscow, AN SSSR Publ., 1963. 250 p.
Poznyak E.D. Avtokolebaniya rotorov so mnogimi stepenyami svobody [Self-oscillations of rotors with many degrees of freedom]. Izvestiya Akademii nauk SSSR. Mekhanika tverdogo tela [News of the USSR Academy of Sciences. Rigid body mechanics]. Moscow, 1977, no. 2, pp. 40-50.
Ragulskis K.M., Ionushas R.D., Bakshis A.K. Vibratsii rotornykh sistem [Vibrations of rotor systems]. Vilnyus, Mokslas Publ., 1976. 190 p.
Simonovskiy V.I. Dinamika rotorov tsentrobezhnykh mashin [Dynamics of rotors centrifugal machines]. Sumy, SumGu Publ., 2006. 126 p.
Symonovskyi V.I. Utochnennia matematychnykh modelei kolyvalnykh system za eksperymentalnymy danymy [Refinement of mathematical models of oscillatory systems from experimental data]. Sumy, SumGu Publ., 2010. 92 p.
Black H.F., MacTernan A.J. Vibration of a rotating asymmetric shaft supported in asymmetric bearing. Journal of Mechanical Engineering Sciences, 1968, vol. 10, issue 3, pp. 252-261. doi: 10.1243/jmes_jour_1968_010_037_02.
Chen X.Q., Jia Y.J., Cheng G.Z. Research on Field Balancing of Rotor. Applied Mechanics and Materials, 2012, vol. 201-202, pp. 83-86. doi: 10.4028/www.scientific.net/amm.201-202.83.
Köenig E.C. Analysis for calculating lateral vibration characteristics of rotating systems with any number of flexible supports. Journal of Applied Mechanics, 1961, vol. 28, issue 4, pp. 585-590. doi: 10.1115/1.3641788.
Li C., Yu. Y., Zhao M. Analysis of Loads at Crankshaft Bearing for Scroll Compressor. Applied Mechanics and Materials, 2012, vol. 160, pp. 42-46. doi: 10.4028/www.scientific.net/amm.160.42.
Li X., Zheng L., Liu Z. Balancing of flexible rotors without trial weights based on finite element modal analysis. Journal of Vibration and Control, 2013, vol. 19, issue 3, pp. 461-470. doi: 10.1177/1077546311433916.
Loewy R.G., Piarulli V.J. Dynamics of rotating shafts. Washington, Pegramon Press Publ., 1969. 300 p.
Memmot E.A. Stability and Testing of a Train of Centrifugal Compressors. ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition (2.06.–5.06.1998). Stockholm, Sweden, 1998, vol. 5, pp. 1-8. doi: 10.1115/98-gt-378.
Morton P.G. On the dynamics of large turbogenerator rotors. Proc. of Institute of Mechanical Engineering, 1965, vol. 180, issue 9, pp. 133-150. doi: 10.1243/pime_conf_1965_180_240_02.
Qiu M., Yan J.F., Chen L., Zhao B.H. Static Analysis on Slewing Bearing with Negative Clearance Based on ANSYS 19. Applied Mechanics and Materials, 2010, vol. 42, pp. 196-199. doi: 10.4028/www.scientific.net/amm.42.196.
Sudhakar G.N.D.S., Sekhar A.S. Identification of un-balance in a rotor bearing system. Journal of Sound and Vibration, 2011, vol. 330, issue 10, pp. 2299-2313. doi: 10.1016/j.jsv.2010.11.028.
Yuan X., Wang T., Fan W.X. The Inner Equilibrium Analysis and Counterweight Design of Engine. Applied Mechanics and Materials, 2010, vols. 44-47, pp. 1051-1055.
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