The“synchronous impact”is a phenomenon that increases the dynamic load of the inter-shaft bearing,when the frequency of the aerodynamic excitation is close to the contact frequency of the inter-shaft bearing.This wo...The“synchronous impact”is a phenomenon that increases the dynamic load of the inter-shaft bearing,when the frequency of the aerodynamic excitation is close to the contact frequency of the inter-shaft bearing.This work addresses the“synchronous impact”phenomenon of an aero-engine.The 104 degree-of-freedom dynamical model of an aero-engine is established by the finite element method,in which the complex nonlinearity of the Hertzian contact force of the inter-shaft bearing with clearance is included,and the multi-frequency excitations such as the unbalanced excitations of the high-and low-pressure rotors and the aerodynamic excitation are considered.A harmonic balance method combined with the alternating frequency time-domain method(HB-AFT)is introduced to obtain periodic responses of the high-dimension complex nonlinear dual-rotor system.The results show that there emerges a peak value of the amplitude-frequency response for the contact frequency harmonic component of the outer ring of the inter-shaft bearing,when the aerodynamic excitation frequency is close to the contact frequency.In addition,the dynamic load of the inter-shaft bearing increases significantly.Moreover,the parametric analysis shows that the“synchronous impact”phenomenon is sensitive to the change of the speed ratio of the high-and low-pressure rotors.The dynamic load of inter-shaft bearing can be significantly reduced by changing the speed ratio by 1%.The results obtained in this paper not only provide more insight into the mechanism of the“synchronous impact”phenomenon but also demonstrate the HBAFT method as a potential semi-analytical tool to explore the high-dimension complex nonlinear system.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.11972129)the National Major Science and Technology Projects of China(Grant No.2017-IV-0008-0045)+1 种基金Department of Science&Technology of Liaoning Province(Grant No.2019BS182)the Educational Department of Liaoning Province(Grant No.LJGD2019009)。
文摘The“synchronous impact”is a phenomenon that increases the dynamic load of the inter-shaft bearing,when the frequency of the aerodynamic excitation is close to the contact frequency of the inter-shaft bearing.This work addresses the“synchronous impact”phenomenon of an aero-engine.The 104 degree-of-freedom dynamical model of an aero-engine is established by the finite element method,in which the complex nonlinearity of the Hertzian contact force of the inter-shaft bearing with clearance is included,and the multi-frequency excitations such as the unbalanced excitations of the high-and low-pressure rotors and the aerodynamic excitation are considered.A harmonic balance method combined with the alternating frequency time-domain method(HB-AFT)is introduced to obtain periodic responses of the high-dimension complex nonlinear dual-rotor system.The results show that there emerges a peak value of the amplitude-frequency response for the contact frequency harmonic component of the outer ring of the inter-shaft bearing,when the aerodynamic excitation frequency is close to the contact frequency.In addition,the dynamic load of the inter-shaft bearing increases significantly.Moreover,the parametric analysis shows that the“synchronous impact”phenomenon is sensitive to the change of the speed ratio of the high-and low-pressure rotors.The dynamic load of inter-shaft bearing can be significantly reduced by changing the speed ratio by 1%.The results obtained in this paper not only provide more insight into the mechanism of the“synchronous impact”phenomenon but also demonstrate the HBAFT method as a potential semi-analytical tool to explore the high-dimension complex nonlinear system.
