Stability Analysis of a Laval Rotor on Hydrodynamic Bearings by Numerical Continuation

Stability Analysis of a Laval Rotor on Hydrodynamic Bearings by Numerical Continuation: Investigating the influence of rotor flexibility, rotor damping and external oil pressure on the rotordynamic behaviour

van Breemen, F.C.

Eling, R.P.T. (mentor)

Mechanical, Maritime and Materials Engineering

Precision and Microsystems Engineering

Engineering Mechanics

2016-08-15

Self-excited vibrations in Laval rotors supported by hydrodynamic bearings, know as oil whirl, induce friction losses and noise, or may even damage the system. This transient dynamic behaviour is caused by the stable and unstable equilibria in the system. To study this phenomenon, this research uses numerical continuation. This method determines the equilibria in the system, their stability and the bifurcations into other equilibria. The sensitivity of these properties with respect to the parameters of the system are studied. The parameters under consideration are the system geometry, rotor stiffness, rotor damping and external oil supply. For this purpose analytic models with the use of short bearing theory and Guembel boundary conditions are made of a rigid, flexible and damped rotor. It extends the results from literature beyond the complications in the model due to the use of numerical continuation, which others did not acknowledge. The novel contribution of the rotor including the damping of the shaft showed to be essential to detect the same dynamic behaviour seen by experimental results from literature. With the addition of the oil feed pressure, the results are strongly improved and are shown to predict the dynamic behaviour of a high speed Laval rotor with reasonable accuracy.

Numerical Continuation
Laval Rotor
Jeffcott Rotor
Stability Analysis
Hydrodynamic Bearing
Short Bearing Approximation
Rotordynamic Behaviour
Oil Whirl
Limitcycle
Bifurcation Detection
MATCONT

http://resolver.tudelft.nl/uuid:0254c08e-4718-4737-9807-387ea30da4cc

Student theses

master thesis

(c) 2016 van Breemen, F.C.