Squeeze Film Damper
In the Squeeze Film Damper node, you specify the geometric dimensions, as well as journal and lubricant properties necessary to model a squeeze film damper.
Damper Properties
Enter the value of the Clearance, C.
Journal Properties
Select SpecifyDisplacement, or Eccentricity and direction. If Displacement is selected, select Journal displacement User defined and enter the displacement values.
The Journal displacement list normally only contains User defined. When combined with another physics interface that can provide this type of displacement, it is also possible to choose a predefined displacement from this list.
If Eccentricity and direction is selected, enter values for the Eccentricity, e, and the Attitude angle relative to local y direction, φy.
Select Velocity of the journalWhirl speed or Velocity field. In the Whirl speed case, select User defined, and enter the whirl speed value. This speed is the angular speed for the circular orbital motion of the journal.
The Whirl speed list normally only contains User defined. When combined with another physics interface that can provide this type of data, it is also possible to choose a predefined angular speed from this list.
When the journal motion is not circular, velocity of the journal can be defined as a velocity field. In the Velocity field case, select User defined, and enter the velocity field of the journal.
The Velocity field list normally only contains User defined. When combined with another physics interface that can provide this type of data, it is also possible to choose a predefined velocity field from this list.
Film boundary condition
This section is only available when Equation type is Reynolds equation in the Physical Model section and Cavitation is not selected in the Cavitation section in the settings for Hydrodynamic Bearing interface.
Select the Film typeSommerfeld or Gümbel. In the Sommerfeld case, a complete 2π film is considered in the net force calculation in the bearing. In the Gümbel case, only half of the film where the pressure is positive (π film) is used for computing the net force in the bearing.
centering spring
Squeeze film dampers themselves are not capable of supporting any static load. Centering springs are provided in the dampers to support the static load. Enter the values of Spring constant, kcs, and Damping constant, ccs, of the centering spring.
Fluid Properties
The default Dynamic viscosity, μ, is taken From material. For User defined, enter a different value or expression.
With the default options, the Density, ρ, is taken From material. For User defined enter a different value or expression. If the Modified Reynolds Equation is being solved, the density is determined automatically by the ideal gas law. If cavitation is enabled, the density is assumed to take the form ρ=ρc exp(βpf), where pf is the fluid pressure, ρc is the density at the cavitation pressure, and β is the compressibility. In this case, enter the values for the Density at cavitation pressure, ρc, and the Compressibility, β.
Film Flow Model
Select Film flow modelNo-slip walls or Slip at walls. In the Slip at walls case, enter the values of Slip length, journal, Lsj, and Slip length, bearing, Lsb.