Abstract: A model for the non-linear axial vibrations of the hydrodynamic
thrust bearing-rotor system in a turboexpander is described. The
axial transient process of the system is investigated. The
time-dependent form of the Reynolds equation is solved by a
finite difference method with successive overrelaxation scheme
to obtain the hydrodynamic forces of the sector-shaped thrust
bearing (SSTB). Using these forces, the equation of motion is
solved by the fourth-order Runge-Kutta method and the Adams
method to predict the transient behaviour of the thrust
bearing-rotor system (TBRS). Also, the linearized stiffness and
damping coefficients of the oil film hydrodynamic SSTB are
calculated. The analyses of the axial transient response of the
system under both linear and non-linear conditions are
performed. The non-linearity of oil film forces can
significantly contribute to the axial transient response.
Conclusions obtained can be applied for evaluation of the
reliability of the TBRS.
Key words: Axial
transient response Thrust bearing-rotor system Turboexpander
*
This project
is supported by National Natural Science Foundation of China. Manuscript received on
April 20, 1999; revised manuscript October 25, 1999
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