Cavitation and Air Entrainment Effects on the Response of Squeeze Film Supported Rotors

This paper analyzes the effects of air entrainment and cavitation on the synchronous response of squeeze film supported rigid rotors. The fluid film force coefficients are obtained from experimental measurements corresponding to a wide spectrum of operating conditions. These conditions include regimes in which air entrainment effects are dominant. Other conditions where vapor cavitation and fluid inertial effects are dominant are included for comparison. The effects of air entrainment are shown to produce a nonlinear response representative of a softening spring effect not previously known to exist in squeeze film dampers.