Abstract
The rotordynamic fluid forces on a closed type centrifugal impeller in whirling motion were measured and simulated for two types of seal, a face seal and a wear ring seal. The rotordynamic fluid forces are destabilizing in the ranges of 0<Ω/ω<0.5 for the face seal and 0<Ω/ω for the wear ring seal, where Ω and co are a whirling speed and a rotational speed of the shaft, respectively. The characteristics of the rotordynamic fluid forces could be understood in consideration of a squeeze effect and the change of resistance of seal due to the eccentricity of the impeller for a swirling flow in the clearance between the front shroud of the impeller and the casing. In a low flow rate, a rotating stall occurred and changed the rotordynamic fluid force drastically around Ω/ω=0.7 for the face seal, 0.6<Ω/ω<0.9 for the wear ring seal.
