Optimisation design for wind turbine mainshaft bearing based on lubrication reliability

Abstract

The lubrication of the mainshaft bearing has a great influence on the safe operation of wind turbines. In this paper, an optimal design model of the mainshaft bearing of a wind turbine is established on the lubrication reliability analysis. The maximum rated dynamic load is set as the design objective. The roller number, roller diameter, roller length and wall thicknesses are design parameters. Constraints are formulated mainly based on lubrication reliability and structure consideration. In the lubrication reliability constraint model, the lubrication reliability criterion was determined by solving the minimum film thickness of numerical calculation model of grease EHL. The reliability of bearing lubrication is calculated by Monte Carlo Simulation, and uncertain variables based on sensitivity analysis are selected to improve calculation precision. In the structure constraints, range for the design variables is determined in terms of requirements of geometric structure and strength. Finally, the mainshaft bearing was optimised and analysed by genetic algorithms. The analysis results show that the rated dynamic load of bearing is improved from 1.3e6 N to 2e6 N. Meanwhile the lubrication reliability is improved about 10%. The model presented shows great advantages and practical usefulness in the mainshaft bearing research of wind turbines.