Study On Hydrodynamic Performance Of A Hybrid Wave Energy Converter Based On Oscillating Water Column And Inertial Pendulum

Since the second half of last century,due to the impact of the energy crisis,Europe has first started large-scale research and development of wave energy.According to the relevant data released by the European Marine Energy Center(EMEC),there are more than 200 kinds of wave energy power generation devices being developed in the world in 2017,and the development of technology maturity is different.All types of devices have certain development prospects.In general,it has achieved rapid development,and has made some achievements in the direction of commercialization.However,compared with the development of offshore wind energy,wave energy has a long way to go from large-scale development and utilization.The main factors restricting the large-scale development and utilization of wave energy are: the actual power generation efficiency of the device is low;The environmental conditions of the sea area where the wave energy power generation device is installed are changeable,which brings the uncertainty of energy development;At present,there is an economic bottleneck in the development of wave energy,and the cost remains high.In view of the current situation that most of the wave energy generation devices are inefficient and fail to make full use of wave energy,a hybrid wave energy conversion device with oscillating water column and inertial pendulum is proposed.Combining the original two different wave energy conversion devices,which can reduce the cost and improve the utilization of a single device.The topic of this paper comes from the research content of National Key R&D Program of China(2018YFB1501904),mainly from the following aspects:(1)Floating oscillating water column(OWC)numerical simulation,using previous model tests of the floating OWC,in the Aqwa to establish the same size of the numerical calculation model.In order to simulate the oscillation of the liquid level in the gas chamber,a rigid piston is set up to replace the oscillating water column,and four fenders are set up above and below the oscillating water column,so that the oscillating water column and the floating body have the same pitch / roll motion,and the oscillating water column and the floating body have relative heave motion in the pipe;By writing an external program?Force 64.f90,adding the nonlinear load force of the air turbine on the float and piston and the nonlinear viscous damping force of the device;The time-domain calculation results are compared with the model test and CFD calculation results in references to verify the feasibility of numerical simulation.(2)For the numerical simulation of the buoy with inertial pendulum power generation device,the experimental model of inertial pendulum power generation device completed by the team in the early stage is selected to establish the same size numerical model in Aqwa.The numerical simulation of three working conditions of inertia pendulum lock,no load and fixed linear load is carried out.The frequency response function and wave energy conversion efficiency of float pitching,inertial pendulum pitching and inertial pendulum pitching relative to floating body are analyzed and compared with model test results.(3)A hybrid wave energy conversion device of oscillating water column and inertial pendulum is proposed.The two models are organically combined.The motion response of the device,the wave energy conversion efficiency and the total conversion efficiency of oscillating water column and inertial pendulum are calculated by using the above verified numerical simulation method.The best PTO load damping is selected to achieve the highest power generation efficiency.