Hydrodynamics Study On Innovative Floating Tidal Current Power Station

As one kind of clean and renewable ocean energy,tidal current energy has recently years attracted more and more attention worldwide.Though a lot of achievement on research of tidal current energy devices has reached,troubles on their installation and maintenance remain unsettled.For this reason,in this paper based on the floating tidal current power station,a series of research have been done by utilizing theoretical,experimental and numerical methods.The research results are expected to provide effective methods and design techniques for the development of more efficient and reliable tidal current devices in the near future.The major working in this paper is sumerized as following.An innovative floating tidal current device with horizontal axis twin turbines is proposed,which featured concise configuration,easier transportation,installation and maintenance in harsh marine environment.And in order to manufacture a high-efficient turbine,the Glauert theory,with consideration of effect of induced velocity,has been applied in the design and optimization of blade which is characterized with high speed ratio,smaller solidity and set-up angle.And then the stability of tidal current device is checked for three typical conditions.The experimental test system for horizontal axis tidal turbine is established,consisting of turbine hydrodynamics test platform and testing program,method for turbine's characteristics and hydrodynamics load.Using this system,one 1kW model turbine and one 10kW prototype have been tested under variety of factors.The experimental results reveale the hydrodynamic performance of horizontal axis turbine,and also can verify the numerical simulation.Additionally,the comparison between lkW and lOkW turbines could be of significance in research of scale effect.Considering the effect of mesh size,turbulence models and solving method,the accuracy and reliability of three-dimension CFD simulation are studied and verified by comparison with experimental results.The interference characteristic between turbine and its support structure is calculated,and the regularity under different parameters is investigated.The flow field and pressure distribution of model are given to analyse the physical parameters which can't be obtained through experiment.A nonlinear elasticity mooring system is proposed,which is suitable for the platform operating in shallow water with heavy load condition.The introduction of elastic rope made the mooring system a strong nonlinear characteristic.Considering the influence of sea flow the catenary equations of multi-component mooring lines have been numerically solved.Comparison among four alternatives,which are chain,chain+buoy,chain+buoy+elastic rope and chain+rope,it's suggested the superiority of elastic rope over others.By altering the water depth and length of elastic rope,the effects of these parameters on mooring system is observed,which can be the theoretical basis for the application of elastic rope.