UNBALANCE RESPONSE OF A FLEXIBLE ROTOR SUPPORTED BY A SQUEEZE FILM DAMPER

This paper investigates the unbalance response of a squeeze film dampe r-mounted flexible rotor. Both concentric and eccentric damper operati ons are examined. Comparison between predicted and experimental result s shows that the 'O' film model is preferred to the 'pi' film model. N ear the first pin-pin critical speed the 'O' film model underestimates the damping effect and overestimates the centralizing force of the da mper. By choosing a lower film rupture pressure in the theoretical mod el, better matches to the experimental results are obtained. The effec ts of air entrainment are shown to produce unsteady responses and jump phenomena of softening spring type. It is concluded that damper model s having constant film rupture pressures do not truly represent the ca vitation problem in squeeze film dampers.