Study On Nonlinear Kinetic Characteristics Of Elastic Disk-Flexible Shaft Rotor System In Gas Turbine

As the increasing attention of our country on equipment manufacture, equipment manufacture play a important role in National economy as Pillar industry of our country in the revitalization plan of ten major industries, which is published recently. As major equipment in equipment manufacture, gas turbine's capacity and Speed of rotation are increasing, and rotor vibration problems caused by the coupling effect between disk and shaft increasingly prominent, so the study of vibration characteristics on elastic disk-flexible axis rotor system has important engineering significance.In this paper, fistly, the dynamic differential equation of elastic disk-flexible shaft rotor system is established by using the component mode synthesis approach. By analyzing and comprising the difference of natural characteristics between elastic disk-flexible shaft rotor system and rigid disk-flexible shaft rotor system, the effect of characteristics of disk-flexible on natural frequency and vibration mode of rotor system is obtained. The coupling effect can decrease the natural frequency of rotor system, and the more the angular velocity, the more obvious. Based on the results of single disk rotor system, the vibration mode of the double disk rotor is analyzed. Moreover discuss the effect of distance between two disks on the natural frequency.Secondly, different model of oil film force are analyzed and compared. Due to Capone model has better convergence and precisionnit, oil film force is insteaded by Capone model. The dynamic differential equation of rotor system incentived by using virtual work principle and modal synthesis method, and provides nonlinear dynamic analysis for sliding bearing-elastic disk-flexible shaft rotor system with runge-kutta method. By discussing effect of angular velocity of rotation on nonlinear dynamics characteristics of rotor system, the order of different point enter into Chaos is achieved.Then, some models of flow induced force are enumerated, and it can be found that Muszynska model has better generality and bigger scope of application. Based on Muszynska model, the dynamic differential equation of rotor system is biuld by oil film force by using virtual work principle and modal synthesis method, and provides nonlinear dynamic analysis for sliding bearing- elastic disk-flexible shaft rotor system with runge-kutta method. According to the time history plot, shaft orbit and spectrum graph of rotor system, effects of angular velocity of rotation, eccentric magnitude, brace stiffness and damping, geometric parameters on stability of system are discussesed.Finally, spatial displacement of cantilever rotating elastic thin plate incentived by base excitation is induced by vector mechanics, and the dynamic model of the plate is builded by using Hamilton principle and the combination method of beam function based on Kirchhoff hypothesis. Analyze the response of cantilever rotating elastic thin plate incentived by sinusoidal excitation by using regular perturbation method, and the analytical solution of the vibration of the plate is obtained. Compared with result calculated by numerical difference method, it shows that results of two methods are similar, and the correctness of the analytical method is proved. To get more information of cantilever rotating elastic thin plate, this paper analyze the natural characteristics of the system, and get the natural frequency and mode of the cantilever rotating plate.In summary, with coupled effect of disk and shaft, oil film force and flow induced force are considered, a dynamic model of disk-shaft rotor system in gas turbine is established, which can accord with engineering practice better. By analyzing and discussing effects of relative parameters on dynamic characteristics and stability of rotor system, and analyzing dynamic response of cantilever rotating elastic thin plate incentived by base excitation, get some useful conclusions are obtained. Summarize and analyze of rotor system mechanics in gas turbine are more roundly, so it has a certain reference value in practical engineering application of gas turbine.