AN EXPERIMENTAL EVALUATION OF SQUEEZE FILM DAMPERS WITHOUT CENTRALIZING SPRINGS

Squeeze film dampers are an effective device for vibration attenuation and stabilization of high speed rotating machinery. Such dampers are either supported by centralizing springs, or are unsupported, the rota tion of the journal of the damper being prevented by 'dogs'. The latte r design is more compact but transient solution procedures often need to be adopted to determine the steady state motion of the damper. Theo retical investigations indicate that for such unsupported dampers, if there is a steady state solution, it may possess synchronous, subharmo nic and superharmonic components, as well as multiple solution possibi lities. Such predictions are evaluated experimentally, using a flexibl e horizontal rotor. This paper describes the salient features of the e xperimental rig, and evaluates experimentally the extent of the validi ty of the theoretical predictions. Goad agreement between theory and e xperiment is obtained provided the 0-film rather than the pi-film cavi tation model is adopted.