Abstract
Lateral fluid forces acting on a rotating centrifugal impeller in whirling motion were analyzed by using unsteady potential flow theory. Impellers operating in diffusers with vanes were modeled and the fluid forces were calculated. Results of fluid forces were converted to mass, damping, stiffness matrices by the Fourier Integral and least square method. The results for impellers with guide vanes showed that the time averaged values of fluid forces remained almost unchanged, while there were significant instantaneous fluctuations due to the impeller/guide vane interactions. And it was found that the elements of matrices for impeller with guide vanes were usually greater than those for impeller without guide vanes.
