Research On Vibration Control Of Rotor System Based On Integral Squeeze Film Damper

Turbomachinery,such as aero-engine,heavy-duty gas turbine,and compressor,are the core equipment of national defense and industrial production in China.In the process of operation,the rotor system of this turbomachinery will inevitably be affected by the base excitation,unbalanced excitation,etc.,resulting in different degrees of vibration in the rotor.However,the traditional squirrel-cage SFD has a high degree of nonlinear oil film force,which may cause nonlinear vibration problems such as bistable response,lockup and non-synchronous in the rotor system.In order to solve the nonlinear problem of the traditional squirrel-cage SFD,it is urgent to develop a highperformance,easy-to-engineer vibration suppression technology to solve the rotor vibration problem of the turbomachinery,which is of great significance for improving national defense capabilities and accelerating economic development.In this thesis,aiming at the vibration problem caused by unbalanced excitation and base excitation in the rotor system,a new vibration suppression technology for the rotor system based on integral squeeze film damper(Integral Squeeze Film Damper,ISFD)is proposed.Through numerical analysis and experimental research,the dynamic characteristics of ISFD are analyzed,and the research on vibration reduction of rotor system based on ISFD is carried out.The main research contents of this thesis are as follows:1.In order to reveal the vibration reduction mechanism of ISFD and to verify the dynamic characteristics of ISFD,an identification method of ISFD dynamic coefficients is proposed,and numerical analysis and experimental verification of ISFD dynamic coefficients are carried out.The influence law of different structural parameters on the stiffness of ISFD is revealed,and the design parameters of ISFD are determined.Using Workbench and n Code Design Life software,the mechanical properties of the ISFD are analyzed,and the stiffness coefficient and service life of the ISFD are obtained to ensure the reasonable structural design of the ISFD.The CFD analysis is carried out with Fluent software,and the oil film force and damping coefficient of the ISFD are calculated.An experiment rig of ISFD dynamic coefficient identification is built,and the stiffness coefficient and damping coefficient of ISFD are measured.The comparison shows that the error of numerical analysis value is about 10%.At the same time,the experimental results show that ISFD has better linear damping characteristics.2.For the rotor system under the action of base excitation,a vibration control method based on ISFD is proposed.The dynamic model and experimental rig of the rotor system under the action of base excitation are established,and the effect of ISFD on the dynamic characteristics of the rotor system is explored.Under a series of base excitation conditions with different excitation force frequencies and excitation force amplitudes,the experimental research of ISFD to suppress the vibration of the rotor system is carried out.The results show that ISFD has stable vibration suppressing performance and can effectively suppress vibration of the rotor system under various base excitation conditions,where the vibration caused by the base excitation is reduced by up to 38.50%.3.The self-designed ISFD structure is applied to the single-disk symmetric rotor system,and it is found through experimental research that the ISFD can effectively suppress the unbalanced vibration of the rotor system under various unbalanced amount and rotational speed conditions,and the reduction of amplitude is about 40%.The ISFD is applied to the four-disk symmetric rotor system,and the research on the vibration reduction of the rotor system under different unbalanced amount and different rotational speed conditions is carried out.The research shows that the unbalanced vibration of the rotor is reduced by about 30% after the ISFD is installed.It can be seen that ISFD can effectively suppress the unbalanced vibration of the rotor systems with various structures under various working conditions.4.The ISFD is applied to the single-disk cantilever rotor system.The simulation analysis shows that ISFD can provide elastic damping support for the rotor system,and reduce the bending stress and strain energy of the rotor system.The research on the vibration reduction of the single-disk cantilever rotor system is carried out under a series of unbalanced amount and rotational speed conditions.The experimental results show that the unbalanced vibration of the rotor is reduced by more than 60% after the ISFD is installed.In addition,increasing the oil supply pressure properly can improve the vibration suppressing performance of ISFD.It can be seen that ISFD has excellent vibration reduction performance,and can significantly reduce the unbalanced vibration of the single-disk cantilever rotor system under various working conditions.5.A novel structure of G-type integral squeeze film damper(G-type Integral Squeeze Film Damper,GISFD)is developed,which has better damping characteristics and provides a new vibration reduction scheme for turbomachinery.The finite element model of GISFD is established and the simulation analysis is carried out to obtain the stiffness coefficient of GISFD.Then GISFD is applied to the rotor system,and simulation analysis and experimental research are carried out.Compared with ISFD,GISFD can more effectively reduce the strain energy and bearing dynamic load of the rotor system,can more effectively suppress the unbalanced vibration of the rotor system,and make the rotor system pass the critical speed more safely and smoothly.The effects of damping fluid viscosity and unbalanced excitation on the vibration damping performance of GISFD are explored.The experimental results show that the damping fluid with larger kinematic viscosity coefficient can improve the vibration reduction performance of GISFD.GISFD has excellent linear damping characteristics,which can effectively reduce the sensitivity of the rotor system to the unbalanced quantity and improve the stability of the rotor system.In summary,this thesis has carried out research on the vibration reduction application of ISFD in different structural rotor systems under a variety of working conditions.It is found that ISFD has excellent vibration reduction performance,which provides new ideas and methods for suppressing the vibration of rotor systems.The research results play a certain reference role in realizing the design of low vibration,high stability and long life of the turbomachinery,and have important engineering application value.