| Heavy-duty gas turbine has been widely applied in the field of integrated gasification combined cycle power generation system(IGCC),gas steam combined cycle power generation system in recent years.Compared with the traditional steam generator sets,gas generator sets have higher technology integration and more complex structure.The high working temperature and pressure of gas turbine bring a huge challenge on the structure designing and material.Rotor system is the core component of gas turbine which is consist of compressor,turbine,and the corresponding supporting system.It is essential to carry out the gas turbine rotor dynamic characteristics analysis for guaranteeing the safe and stable operation of gas turbine.The work in this paper is supported by the central college major achievement transformation project in Beijing “Research and application of large gas turbine generator sets monitoring and protecting system”(ZDZH20141005401).Taking the multiple disks rod fastening rotor of gas turbine as the object,the nonlinear dynamic response characteristics of rod fastening rotor under fault condition are researched.The study will contribute to the further understanding of the nonlinear dynamic characteristics of a rod fastening rotor bearing system;meanwhile,the corresponding results can provide the guidance for the design,manufacture,and operation reliability of gas turbine.The main work in this paper are as follows:(1)Carried out the nonlinear dynamic characterisitics analysis of a rub-impact rod fastening rotor bearing system.A model of the rod fastening rotor bearing system under rub-impact condition is proposed considering nonlinear contact characteristic between disks,nonlinear oil-film force,unbalance mass,etc.The influences of rotating speed,stator radial stiffness,and unbalanced mass eccentricity on the rod fastening rotor system are diccussed respectively by using numerical integration method.The studies indicate that the responses of rub-impact presents a big difference among integral rotor and rod fastening rotor;rotating speed,stator radial stiffness,and unbalanced mass eccentricity have a big influence on the system response,rub-impact force mainly affects the system response on high speed region.(2)Studied the nonlinear dynamic characteristics of a rod fastening rotor bearing system with initial permanent deflection.The initial bending length is considered in the dynamic model of rod fastening rotor bearing system,system responses are calculated using numerical integration method,than discuss the influence of rotating speed and initial bending length on the system response.The results show that it is unsuitable to take the rod fastening rotor as an integral rotor in analyzing the nonlinear dynamic response of rod fastening rotor bearing system with initial permanent deflection.The initial permanent deflection fault mainly affects the response characteristics of low speed region,the system instability speed enlarges with the increase in initial bending length,meanwhile,the chaotic motion area decreases gradually.(3)The nonlinear coupled dynamics of a rod fastening rotor under rub-impact and initial permanent deflection are researched in this paper.The dynamic model of the rod fastening rotor bearing system considering the initial permanent deflection,contact characteristics between disks,nonlinear oil-film force,and rub-impcat force is established based on D'Alembert principle.The influences of rotating speed,stator radial stiffness,and initial bending length on the nonlinear coupled dynamic response of the system are discussed.It can be seen from the results that the nonlinear dynamic response of the rod fastening rotor bearing system varies with the fault types.Compared with the single fault type,coupled faults have a significant influence on the dynamic characteristics of rod fastening rotor bearing system.In low speed region,the system response is mainly affected by initial permanent deflection,the rub-impact fault gradually becomes the dominant factors influencing the system response characteristics with the increase in rotating speed.(4)Carried out experimental study on the multiple disks rod fastening rotor system.In this paper,the multiple rod fastening rotor experimental platform and vibration testing system are built.The modal parameter identification method is adopted to recognize the structural characteristics of multiple disks rod fastening rotor under different pre-tightening plans.The studies indicate that the first order bending vibration natural frequency and the second order bending vibration natural frequency are gradually increasing with the rise of rod tightening force,meanwhile,the stress distribution of contact interface has a effect on the natural characteristics of structure. |
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