A technological solution, frequently used to suppress vibrations in rotating machines, consists in adding the damping devices between the rotor and its frame. This is enabled by dampers working on the principle of squeezing thin classical or magnetorheological oil film. The full Navier-Stokes equation, Reynolds equation or modified Reynolds equation is used to determinate the nature of the pressure distribution in the thin oil film. The nonlinear hydraulic forces in the oil film are obtained by the integration of the pressure distribution around the damper circumference and also along its length in the axial direction for, both, non-cavitated and cavitated operating regimes. The developed computational approach, for determining the damping and stiffness coefficients, is based on the linearization according to instantaneous kinematic parameters. The damping and stiffness characteristics computed according to the Navier-Stokes equation are compared to the ones, that resulted from the application of the Reynolds equation. Realized computational simulations confirmed, that the electric current in the magnetorheological damper makes it possible to achieve the higher damping in a wide range of the rotor operation speeds.

This work has been supported by the Ministry of Education, Youth and Sports from the National Programme of Sustainability (NPU II) project „IT4Innovations excellence in science - LQ1602“ and by the Czech Science Foundation 15-06621S.