Study On Rotor Unbalance Parameters Identification And Optimization Method In Rotating Machinery

Rotary machinery such as centrifugal pumps,steam turbines,compressors,as well as aero engines are playing a decisive role as important machines in industrial field and even in national defense.Rotor unbalance is a common failure of rotating machinery,which not only affects the healthy operation of the machine,but also easily induces other secondary failures.How to effectively eliminate rotor unbalance is of great significance for maintaining the normal operation of the machine and ensuring the long-term operation of the machine.An effective way to eliminate unbalance is rotor dynamic balancing.It is time-consuming and laborious to add trial weight,multiple start-up to carry on field dynamic balancing.If rotor unbalance parameters can be accurately identified,the trial would be added directly,so that dynamic time and cost would be reduced.In view of this,as for the unbalance identification of the rotor system of rotating machinery,unbalance parameters identification methods for the flexible rotor system based on the optimization algorithm are presented to identify unbalance parameters including location of the faults,with no more trial weight and start-up.The main work of the thesis is shown as follows:(1)A rotor unbalance parameter identification method based on modal expansion combined with the use of optimization algorithms is proposed.The modal expansion theory is used to estimate the equivalent unbalance force,meanwhile to identify the location of faults in single-disk rotor system.An objective function containing unbalance parameters was optimized by antlion algorithm,genetic algorithm,simulated annealing algorithm,and fruit fly optimization.Simulation and experimental results showed that the identification results of the fruit fly algorithm were relatively better.This method can accurately identify unbalance parameters of the rotor.(2)A rotor unbalance parameter identification method based on the inverse problem combined with optimization algorithm is proposed.The relationship between unbalance response,unbalance and frequency response function was established in single-disk rotor system.Vibration data is used to estimate the equivalent unbalance force and unbalance parameters were identified by different optimization algorithms.Simulation and experimental results show that the identification results of fruit fly algorithm were relatively better.The proposed unbalance identification method can accurately identify unbalance parameters.(3)In order to solve the limitation of the axial position of the unbalance needs to be obtained by inverse problem,a method integrated modal expansion/inverse problem combining with the use of optimization algorithms is proposed for unbalance identification in double-disk rotor system.The modal expansion technique is used to identify axial position of unbalance firstly.Then the inverse problem method is used to estimate the equivalent unbalance force.After establishing the objective function,unbalance parameters were identified by using different optimization algorithm.Simulation and experimental results show that:the identification results of the genetic algorithm were relatively better.Unbalance parameters can be accurately identified by the proposed method.The dynamic balancing was carried out according to the identification results.After balancing,the vibration amplitude decreased obviously,which validated the reliability and effectiveness of the proposed method.