The paper presents the analysis of a compressor employing the method of cyclic symmetry incorporating gyroscopic effects and geometric nonlinearities of the whole elastic system based on the finite element method. Because of numerical difficulties, the solution of the resulting eigenvalue problem is limited to a small number of DOF’s. For this reason the calculation of the impeller as an elastic model is performed including the prestress and nonlinearities due to rotation. With the knowledge of these frequencies and the mass moment of inertia of the impeller, an equivalent system of rigid disk and speed dependent spring is included in the rotor dynamic model. Further, the gyroscopic effect, speed-dependent bearing coefficients, and the elastic effects due to the rotation of the impeller are included in the rotor dynamic model. For illustration purpose, calculation is performed on a fan rotor and the results are compared with those obtained from experiment.

Issue Section:
Gas Turbines: Structures and Dynamics
Topics:
Compressors, Rotors, Impellers, Dynamic models, Rotation, Bearings, Disks, Eigenvalues, Finite element methods, Inertia (Mechanics), Springs
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