Analysis on dynamic characteristics of a dual rotor-rolling bearing coupling system for aero-engine

Based on the bearing dynamics and rotor dynamics models,the nonlinear dynamic mathematical equations were established to describe the dual rotor-rolling bearing coupling system.Newmark finite element method was used to solve the equations.The influences of the rotor speed,intershaft bearing clearance,rollers number and supporting bearing geometry parameters on dynamic characteristics of the dual rotor system were analyzed and verified experimentally.The results shows that:(1) The cylindrical roller intershaft bearing has a significant influence on dynamic characteristics of the dual rotor system,and the stable system operation can be realized when the original clearance is 20 μm.(2) Dynamic characteristics of the dual rotor system can be affected directly by groove curvature radius coefficients of inner and outer rings.(3) The node displacement of coupling between the high-pressure rotor and the low-pressure rotor decreases with the rise of the high-pressure rotor speed,and increases with the drop of low-pressure rotor speed.(4) The theoretical calculation of the coupling node displacement of intershaft bearing is matched with experimental value,and the maximal error is about 18.7%.