Research On Hydrodynamic Performance Of Horizontal Axis Tidal Current Turbine In Complex Flow Field

The ocean contains a lot of renewable energy,especially tidal energy,which has broad development prospects because of its high energy flow density and strong predictability.At present,the horizontal axis turbine with good starting performance and high energy utilization has become the main form of tidal current energy capture device.However,the actual marine hydrological environment is complex,and the seawater will form various complex flow fields under the influence of terrain,waves and other factors,which will have an important impact on the hydrodynamic performance of the turbine.At present,CFD simulation or test methods are mostly used to study the hydrodynamic characteristics of hydraulic turbine in complex flow field,which often consumes a lot of calculation time or experimental cycle.Therefore,it is necessary to develop a fast and effective prediction method for complex flow field to meet the needs of optimal design and accurate control.Based on the unsteady blade element momentum(BEM)theory,the hydrodynamic characteristics of horizontal axis tidal current turbine(HATCT)in complex flow field are studied in this paper.Based on the traditional BEM theory,combined with the coordinate system transformation method,dynamic inflow model and dynamic stall model,the unsteady hydrodynamic calculation method of HATCT is established through independent programming.And compared with the experimental and CFD simulation results,the effectiveness of the numerical method is verified.According to the marine environment dominated by shear flow,the influence law of flow field shear rate on hydrodynamic coefficients of HATCT is calculated and explored;The effects of shear rate,oscillation amplitude and oscillation frequency on hydrodynamic coefficients of hydraulic turbine are analyzed including the surge and pitch motion of platform.According to the of wave-current environment,the effects of wave period,wave amplitude and immersion depth on the hydrodynamic coefficients of HATCT are studied;The influence law of the amplitude and frequency of the oscillation on the hydrodynamic coefficients of the HATCT is analyzed when the wave is combined with the platform’s surge and pitch motion.It can quickly calculate the power and load characteristics of HATCT in complex flow field,provide reference for its structural check,performance analysis,optimal design and control,and has academic significance and application value in theoretical research and engineering practical application.