Load Analysis Of Vertical Axis Turbine In Complex Sea Conditions And Fatigue Analysis Of Connecting Structures

Floating vertical axis tidal generator will be affected by the complex environment load in marine environment,which will makes the whole generator sway violently and affects the performance of the vertical axis turbine.Therefore,the generator will reduce the life expectancy and even break down during the operation.So it is necessary to study the movement and force of floating vertical axis tidal power generator in complex sea conditions.In the whole structure,the flange connection structure is the weak link of the whole generator because the bolts of flange are prone to fatigue fracture under complex sea conditions,which is easy to cause a major safety accident.Therefore,this paper focuses on the study of the movement and stress of floating vertical axis tidal generator in complex sea conditions,and analyzes the static strength and fatigue life of the flange connection structure.Firstly,this paper analyzes the complex ocean environment loads,mainly describes theory of the wind load,wave load and current load.Besides,the irregular wind load and wave load movement are solved by using wind spectrum and wave spectrum,and the work condition and extreme sea condition of floating tidal generator are defined.Secondly,the dynamic analysis of the carrier of floating tidal power generator is carried out,and three coordinate systems are established to describe the motion of the floating carrier.By analyzing the motion responses of floating carrier in complex sea conditions through AQWA,the motion responses of six degrees of freedom are obtained in frequency domain and time domain.The force on the main shaft of the hydraulic turbine is obtained by the means of the single disk single pipe model and the blade element theory.According to the analysis of the hydrodynamic characteristics of the floating carrier of the generator through AQWA,the related parameters of the design wave are selected.According to the parameters of design wave,the fluid force and inertia load are mapped into the ANSYS static analysis module through AQWA-WAVE,and the static strength of the whole floating tidal generator and the contact strength of bolts structure which connects flange with flange with larger stress are analyzed.Finally,the time domain analysis results are taken shape as load spectra and the fatigue life of flange connection structure is analyzed by nCode.