Investigation of dynamic behavior of auxiliary power unit with rotor in gas foil bearings

摘要

Auxiliary power unit rotor static and dynamic characteristics were investigated for four rotor supporting schemes. Auxiliary power unit rotor supported in roller element bearings was compared to similar rotor supported in gas foil bearings and to intermediate option of rotor supported in combination of gas foil bearing and ball bearing. Support reactions under the action of weight, imbalance and flight acceleration forces are determined for all schemes. Rotor support reactions gives an opportunity to select gas foil bearing type and dimensions. Rotor model for nonlinear analysis is based on beam finite elements and verificated with corresponding solid model by comparison of eigenfrequencies. This model taking into account supports casing stiffness characteristics determined using 3D finite-element models and nonlinear stiffness properties of roller element and/or gas foil bearings. Different schemes of rotor supporting are analyzed for support loads, eigenfrequencies and nonlinear vibration orbits and amplitudes that allows selecting major problems for upgrading of auxiliary power unit rotor with gas foil bearings.