The performance of squeeze film dampers and liquid film bearings
can be affected by the occurrence of cavitation. The compressibility
of the liquid-gas mixture alters the pressure distribution and the
velocity field inside the fluid film, which negatively impact the load
capacity, stiffness, and damping characteristics of the fluid film.
This paper presents the study of the impact of gaseous cavitation
on the damping performance of a squeeze film damper. The quasiperiodic pressure change inside the fluid film is extracted when the squeeze film damper moves over a prescribed, measured trajectory. The pressure is measured as a function of time at two axial locations
along the bearing. A theoretical model of the quasi-periodic pressure distribution inside the bearing is developed and uses these measurements to yield the force components acting on the bearing. Finally, combining the resulting force components with the imposed bearing
motion, the damping performance is determined in terms of energy extracted from the bearing motion in time. The study is performed without cavitation and with various amounts of volumetric cavitation levels for two different ratios of bearing length to diameter. The results are quantified as function of the volumetric gas ratio, whirl
speed, and amplitude. In addition, the dynamics of the pressure
developed inside the fluid film is correlated to the visually observed
progress of the cavitation regions during the bearing whirl.
