DETERMINATION OF CRITICAL SPEEDS OF A CENTRIFUGAL PUMP IMPELLER IN ANNULAR SEALS

摘要

The paper deals with combined transverse and angular vibrations of a single-disc impeller in annular seals. The formulated equations of vibrations include additional (i.e., inertia, damping, potential, gyroscopic and circular) hydrodynamic forces and moments occurring in clearances of non-contact seals. The study involved performing digital calculations to determine the natural frequencies in two models of the rotor, both for constant pressure drops in seals and for a square relationship between the pressure drops and the rotational frequency of the impeller. It was also necessary to estimate the influence of the conicity of the annular clearance gaps in non-contacting seals on the natural and critical frequencies of the rotor.