Thermoelastic Coupling Research On Rod-fastened Rotor Dynamic Characteristics

Based on the characteristics of the disc rotor bar gas turbine, the rough surface elastoplastic contact model and the rotor dynamics model are applied. This paper deals with the frictional contact between the rotor disc and its thermoelastic coupling nonlinear problem, and hopes to further improve the modeling precision of the disc rotor. In this paper, based on the rotor thermoelastic coupling dynamics, the following work has been done:First of all, based on the rod disc interface roughness of the rotor disc, the solid surface contact problem was analyzed, and at the same time considering the elastic-plastic deformation of asperity, combined with the Mandelbrot - Tian (M - T) fractal network model and the classical contact heat conduction theory, the Cantor set fractal theory, which is not dependent on the observation scale, are chose to obtain the contact surface heat transfer coefficient by writing the programs.Secondly,using the finite element analysis software to establish three-dimensional finite element analysis model of heat transfer of the rotor disc,by determining the boundary conditions of the model, the step load and simulation operating mode, the thermal expansion and the change of the contact pressure of pull rod rotor wheel is obtained by simulation calculation, the change of contact surface heat transfer coefficient and stress field numerical influence is less than imagined.Finally, three dimensional finite element model of temperature field and pull rod combination of prestressed modal analysis for more accurate rotor are established by the application of calculation and analysis data , hope to be able to design the working speed range that can avoid the natural frequency of structures.The research of thermoelastic coupling rod rotor dynamics can reduce rotor stress value of the maximum stress area, increase rotor stability , resist to deformation ability ,decrease the rotor unbalance response value and has the important value of engineering for the optimization of rotor material selection, structure design and gas turbine rotor life management application.