Hydrodynamic Performance Analysis Of The Two-raft-type Wave Energy Converter

As a kind of ocean energy,wave energy has the characteristics of wide distribution,high energy density and low clean pollution.It has great prospects in the future development and use,and has gradually become the focus of attention of all countries.In recent years,the research on the geometry of the raft wave energy device has gradually increased.However,in the actual environment,when designing the raft wave energy device,the problem of efficient utilization of wave energy has not been well solved,which has become a serious obstacle to the development of wave energy industrialization.At present,many scholars have preliminarily studied the effect of waves on the hydrodynamic performance of raft wave energy devices,but for the further optimization design research after the comparative analysis of various raft shapes,the systematic research on the body coupling between two rafts and mooring equipment under waves and currents has been carried out,and few results have been published.Therefore,it is of great academic value and engineering significance to carry out the research on the hydrodynamic performance of the raft wave power generation device under the conditions of wave and wave current for improving the efficiency and reliability of the raft wave power generation device and improving the overall performance of the device.(1)Aiming at the research and verification analysis of raft wave energy power generation device,a numerical wave tank is established based on CFD method.The feasibility of wave generation method is verified by analyzing the grid convergence and time step convergence.On this basis,the numerical analysis of two raft wave power generation devices is carried out to verify the interaction of waves and wave current with objects,and the effectiveness of the numerical calculation method is verified by comparing with the published experimental data.(2)Aiming at the hydrodynamic characteristics of raft wave energy devices with different shapes,based on the numerical method established in(1),the vertical and horizontal forces,relative pitch motion amplitude,and conversion efficiency of wave energy devices under wave conditions are numerically analyzed,and the wave period,wave height,relative direction,spacing,top angle degrees,draft ratio,hinge point position,bottom shape,center of gravity height,length The influence of parameters such as PTO on the hydrodynamic characteristics of wave energy devices.Based on this,a raft parameter combination corresponding to the maximum energy capture coefficient is established to optimize the structural parameters of the device.(3)Based on the numerical method established in(1)and the numerical model established in(2),the numerical analysis of the relative pitch motion amplitude and conversion efficiency of the wave energy device under wave and current conditions is conducted for the raft wave energy device with optimized structural parameters,and the effects of PTO parameters,wave parameters,and flow velocity on the performance of the optimal raft wave energy conversion device are obtained.On this basis,aiming at the mooring system of the installation under the action of waves and currents,and based on the energy capture characteristics of the raft type wave energy conversion device,firstly,the quality of the mooring equipment is analyzed and compared,and the optimal quality of the mooring equipment is obtained;Then ten types of mooring systems based on single mooring are proposed.Through comparative analysis of the conversion efficiency of these ten types of devices,nine dual mooring modes are combined to obtain their impact on the optimal raft wave energy device,providing a reference for the design of the wave energy conversion device mooring system.