| As a large-scale rotating machinery, gas turbine is widely used in aviation, aerospace, water, transport and electricity and other industrial fields, it plays a vital role in modernization of national defense and our country economic society development. In recent years, with the increasing of the gas turbine capacity and rotational, rotor vibration problems have become increasingly prominent. So the research which is on dynamics of gas turbine system has important engineering significance.In this paper, firstly according to the drawings of a gas turbine, the three-dimensional model of blade-disc-rotor system has been established with the SolidWorks software. Then applying reciprocal inertia principle, it has got the equivalent simplified disc-rotor system, and established two kinds of transfer matrix model that one is centralized quality model and the other is distribution of quality model. Through the modal analysis of transfer matrix model, natural frequencies and mode shapes of the gas turbine disc-rotor system have been obtained, and to compare the results of two models, it has verified the validity of the method.To further study the natural vibration characteristics of the system, the gas turbine structure model of blade-disc-rotor system has been established. With the superiority of ANSYS substructure method, system mode is solved again. In the meanwhile, it has made an analysis of static frequency with the overall method and substructure method respectively which is based on ANSYS software. By comparing the results of two methods, it has verified the accuracy and superiority of the ANSYS substructure method. In addition, it has compared dynamic frequency result of the ANSYS substructure method with the frequency result of transfer matrix method; the validity of the two methods has been verified.Imbalance is the most common vibration faults of the rotor system. In order to analyze that the unbalance takes influence on vibration characteristics of the gas turbine blade-disc-rotor system, it has solved the system unbalance response with the transfer matrix method and ANSYS substructure method respectively. And explore that the influence of eccentric position and size of the eccentric mass is on unbalance response of the system. Meanwhile, also for the results of two methods unbalance response obtained are compared, and it has verified the accuracy of two methods. Based eccentric impact factors on the response characteristics of unbalanced, it has illustrated the application of the unbalance response in the rotor balancing.Blade disc system vibration is the main source of vibration on turbine blade-disc-rotor system, so the separate analysis of them is very necessary. With ANSYS software, it has established two kinds of finite element model of blade disc system that one is the basic sector model and the other is the full model. Respectively under the non-rotating state and the rotation state, blade disc system modal has been solved. It also has analyzed the forced vibration response in the aerodynamic loads. Finally, the finite element model of the blade disc system has been established under different aspect ratio in fixed blade width and fixed blade length. And explore that the influence of aspect ratio is on natural vibration characteristics of blade disc system.The gas turbine blade-disc-rotor system as the research object in this paper, by means of the transfer matrix method and ANSYS substructure method, it has solved the intrinsic mode and unbalance response of the system, analyzed the forced vibration response for the single blade disc system in the aerodynamic loads, and meanwhile explored that the influence of aspect ratio is on natural vibration characteristics of blade disc system. For the blade-disc-rotor system dynamics problems, this research is a more comprehensive overview and analysis; it has important reference value in the practical application of engineering. |
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