Modeling And Experimental Research On Grinding Temperature Field Of Wind Turbine Blades

With the increase of wind power installed year by year,the demand of wind turbine blades,as one of the important components of wind turbine,is increasing exponentially.At the same time,the wind turbine blades used perennially will be damaged by natural disasters such as wind erosion.If the damaged blades can be repaired and reused,the production cost will be reduced.In the process of blade production and repair,grinding is an important process.Traditional manual grinding has high labor intensity,low efficiency,bad working environment and poor uniformity of blade surface quality.In order to overcome the above shortcomings,a SEA-like flexible end-effector-assisted mobile manipulator suitable for large-scale surface grinding is proposed.To address the problems of thermal damage and difficulty in real-time temperature measurement during wind turbine blade grinding,the temperature field of composite-materials surface grinding with cup wheel was studied in this paper.At present,the analytical model of temperature field based on uniform heat source has some problems,such as low accuracy of temperature prediction,so this paper,considering material removal and grinding force distribution,combines heat source shape with heat flow distribution to establishes an non-uniform heat source model with different function distribution in circumference and radial directions under cylindrical coordinate system for surface grinding by cup wheel.And then the analytical model of temperature field under above heat source is deduced.The approximate analytical method has strong logic in the derivation process,but the derivation process is extremely complex in the face of the heat conduction problem under complex boundary conditions.In order to solve the above problems,a three-dimensional transient heat conduction numerical model for composite surface grinding is established by using computer-aided finite element method.The results show that the addition of natural convection heat transfer or forced convection heat transfer boundary conditions improves the accuracy of grinding temperature prediction,and provides a more accurate theoretical basis for preventing grinding burn and guiding heat dissipation of surface grinding by cup wheel.In order to verify the analytical and numerical models of temperature field,the current grinding temperature measurement technology is analyzed and compared.In this experiment,artificial thermocouple method and high-definition infrared measurement technology are used to measure the grinding temperature field and temperature curves of special area points.The experimental results verify the accuracy of the heat source model and the analytical and numerical models of temperature field.The new model reduces the accuracy of temperature prediction from 20% to 6.5%.The grinding depth has a great influence on grinding temperature,and the feed velocity of workpiece has the least influence on grinding temperature.The research results of this paper provide theoretical basis for preventing grinding burn and optimizing grinding parameters.