Research On Fluid-solid Load And Vibration Characteristic In Transmission System Of Doubly-fed Wind Turbine

Because of bad working environment of wind turbines,wind turbine is affected by irregular change wind load and strong wind impact load throughout the year.Meantime in order to obtain more wind in the process of equipment running,it often need to pitch and yawn,which will impose additional load on wind turbine.Combined with reasons of overhead and difficulty of maintenance,reliability and service life of wind turbine are much higher than the general mechanical system.As main mechanical equipment of wind turbine,the transmission system is affected by unstable random dynamic load and fatigue stress which are greater than other transmission mechanism,which make transmission system frequently occur fault and seriously affect the safe operation reliability of wind turbine.Therefore,it more important practical significance of stable and reliable running that study dynamic behavior and vibration characteristics of wind turbine transmission system.In this paper,based on virtual test technology,fluid-solid coupling theory,random vibration parameters and nonlinear contact method,etc.,combining the theoretical analysis and calculation method,experimental measurement and finite element analysis method,study effect of wind load and running load on low speed shaft,gear box,high speed shaft,shaft coupling and generator of transmission system under wind turbine running environment,and study some related problems of transmission system action,dynamic and static mechanics and reliability sensitivity under wind load and running load coupling characteristics.Main research content of the article is as follows:(1)By measuring wind resource data of NeiMenggu ZhuoZi No.2 wind farmer and analyzing statistical data,proposing synthetic curve of wind resource distribution.With function of Weibull wind resource distribution and method of least squares estimation,Utilizing mathematical analysis software MATLAB to analyze data second time and calculate location parameter c and shape parameter k,and building wind resource engineering mathematics model.In order to provide basis of wind famer design,by comparing calculation curve and measured curve and fixing parameter of wind resource mathematical model,simulate and get the size of wind load when wind turbine run.(2)With viscous fluid mechanics theory and computational fluid dynamics theory,Considering fully aerodynamic load time-changing law,air wake entangled and turbulent load of wind turbine in actual running environment.And studying load change law of wind shear,tower shadow and braking load in process of wind turbine running,calculate internal working vibration load.Based on fluid-structure coupling analysis theory and control theory of wind turbine,study calculation method of wind turbine drive system coupling vibration load spectrum.(3)According to structure characteristics and mechanical characteristics of wind turbine,with dynamic simulation software ANSYS/LS-DYNA,set up reasonable quality node,unit type and boundary conditions to simplify system model.By loading coupling load spectrum,study transmission stiffness and structural damping in vibration characteristics influence of transmission system and put forward theory analysis method of impacting natural frequency with transmission stiffness and structural damping.With engineering design of transmission system to build virtual prototype,Utilizing QR damping method to analyze modal of whole machine and natural frequency,spectrum,transient dynamics and contact.By extracting vibration characteristic of key points,ensure vibration sensitivity of transmission stiffness and structural damping and put forward method of optimization design for transmission system.(4)In order to reduce vibration value of wind turbine transmission system running,improve operation reliability of wind turbine.With sensors,data acquisition unit,power amplifier and PC to build vibration monitoring system,collect data of vibration displacement,velocity and acceleration of wind turbine transmission system.Using software MATLAB and OrginalLab to analyze data,illustrates rotation speed in all levels of drive shaft,eccentricity and dynamic incentive to affect system vibration,and put forward method of reduce failure with adjust parameter reasonably of v-P control curve.(5)Studying reliability sensitivity of whole transmission system with simulation of dynamic and static mechanics.Statics analysis,with low speed shaft material density,low speed axial material elastic modulus,shrink disk material density,shrink disk material elastic modulus as random variables,dynamic analysis,with aerodynamic load and internal external excitation load as random variables.Studying probability sensitivity of wind turbine transmission system for random variables by using analysis method of Monte Carlo mechanical reliability sensitivity under influence of fluid-structure interaction of wind turbine drive system.Base on research above,mastering comprehensively method of load calculation engineering and influence law of each load for whole wind turbine and parts under wind turbine running condition,which lay the foundation of engineering design for wind farmer and reliability design,optimization design for wind turbine.