Abstract
In this paper, a simplified dynamic model of a dual-rotor system coupled with blade disk is built, and the effects of blade parameters of an aircraft engine on the dynamic characteristics of a dual-rotor system are studied. In the methodology, the blade is simplified as a cantilever structure, and the dynamical equations are obtained by the means of a finite element method. The amplitude-frequency response curves and orbits of shaft centre-vibration shape diagram are used to analyze the effects of blade parameters on dynamic characteristics of a dual-rotor system. The results indicate that the properties of the blades have huge impacts on the critical speed and other dynamic characteristics of the system. With an increase of the length of the blade, the second-order critical speed decreases obviously, but the first-order critical speed is almost invariant; this means that the blades attached on the low-pressure compressor do not affect the first-order critical speed of the dual-rotor system. Meanwhile, note that the high-pressure rotor and low-pressure turbine rotor can excite the first-order resonance of the dual-rotor system, while the low-pressure compressor rotor can only excite the second-order resonance, and then the dynamic model of this six-point support dual-rotor system can further be simplified as a relatively independent single-rotor system with one disk and a four-support dual-rotor system with dual disks.
Highlights
As one of the most important components of the aeroengine, the blades, mainly including rotor blades and stator blades, have huge effects on the performance and safety of the whole engine system [1]
Lesaffre et al modeled a flexible fully bladed rotor in the rotating frame, and a full set of flexible blades was modeled by Euler–Bernoulli beams clamped in the disk [2]. e influence of shaft bending on the coupling vibration of a single rotor-blade system was analyzed by Li et al [3, 4]
In Li’s work, the single rotor system was composed of a continuous flexible shaft and a rigid disk, and the disk was regarded as a mass point and the blade was derived by using the Euler–Bernoulli beam model
Summary
As one of the most important components of the aeroengine, the blades, mainly including rotor blades and stator blades, have huge effects on the performance and safety of the whole engine system [1]. For the single blade, considering the influence of aerodynamic forces, Zhang et al [9] simplified the blade into a cantilever beam with thin-wall structure and studied the nonlinear vibration problem of the compressor blades. Cao et al [21] simplified the blade into a cantilever beam structure and deeply studied the dynamic model of the blade-rotor system with the consideration of the factors such as sliding bearing, squeeze film damper, and gyro effect, respectively. Some simplified dynamic models of the dual-rotor system were built [27,28,29], which can be well used to investigate the nonlinear response characteristics for aeroengine dual-rotor system In these models, the influence of blade parameters was not fully considered.
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