Influence of impeller shroud forces on turbopump rotor dynamics
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The shrouded-impeller leakage path forces predicted by Childs (1987) have been analyzed to examine their influence on pump rotordynamics. Because of the characteristics of these forces, they can not be modeled with traditional stiffness, damping, and mass matrices. They are modeled in the present study by adding whirl-frequency dependent direct and cross-coupled stiffness terms to the traditional stiffness, damping, and mass coefficients. A simple Jeffcott rotor model is used to examine the influence of the impeller-shroud forces and wear-ring seal forces on a double-suction, centrally-mounted, single-stage pump. The traditional methods of dynamic system analysis were modified to incorporate the impeller forces and yielded results for the eigenproblem, frequency response, critical speed, transient response and an iterative technique for finding the frequency of free vibration as well as system stability.
author list (cited authors)
Williams, J. P., & Childs, D. W.