Thermal And Structural Characteristic Analysis And Research Of Case For Wind Turbine Generator Gearbox

With the development of wind turbine generator towards higher power, higher reliability of wind turbine generator gearbox is in demand. The further study of thermal and structural properties for wind power gearbox can enhance the reliability and life of Gearbox. In this paper, megawatt-class wind turbine generator gearbox is considered as the research object. Finite element analysis method is used to analyze static and thermal-structural coupling properties of the case, and steady temperature field of case and transmission parts in high-speed class. The Matlab simulation software is applied to establish the steady thermal balance model of gearbox and the calculate method of the balance oil temperature for gearbox is given.Firstly, the theory of finite element static analysis is introduced. For the features of structure and load conditions of gearbox, load boundary conditions required by the finite element analysis are determined. Three dimensional models of all components for case are established, which are overall assembled, and carried into ANSYS software to do structural static analysis. The stress and displacement field of case structure are obtained, and strength and rigidity of structural are analyzed.Secondly, according to the basic theory of steady-state heat conduction and heat convection, the total heat value of gearbox is calculated, as well as heat dissipation value of each part. On the basis of simplified model for gearbox, the steady-state thermal equilibrium model about heating and dissipating of transmission gearbox is established using lumped parameter method, and iterative procedure of solving steady-state heat balance equation are constructed by Matlab software, in order to obtain the temperature curves over time of lubricating oil in case, while the thermal average temperature of every parts of case, and the heat dissipation valve of every dissipation part are obtained.Thirdly, three-dimensional entity model of case and high-speed class transmission parts is established. According to finite element thermal and thermal-structural coupling analysis theory, the thermal boundary conditions when the ambient temperature is highest and thermal equilibrium state are determined. Steady-state thermal analysis of the gearbox system is done by ANSYS software, to get steady-state temperature field distribution of case and high-speed transmission parts. The Matlab simulation results and the finite element calculating values are compared with the experimental data, which show that the analysis method for gearbox is correct. On this basis, thermal-structural coupling analysis of case is done, to obtain the deformation value under the action of force and heat. Deformation values of four bearing bores in high-speed class on case are obtained and parallelism value of the shaft caused by the deformation of case is calculated. The influences about the deformation of case on the gear mesh error are analyzed, which provides a theoretical basis for calculating the high-speed class transmission gear mesh total error.Finally, the effects about the changes of the lubricating oil viscosity on the heating of bearing in high-speed class and the temperature rise value of bearing outer ring are calculated.