Study On The Hydrodynamic Performance Of A New Type Of Buoyant Pendulum Wave Energy Converter

With the global warming,the shortage of fossil energy and environmental pollution have attracted the common attention of governments of all countries.In response to these problems,countries in the world are striving to find and develop alternative,clean,and renewable new energy sources.As a kind of high-quality renewable energy,marine energy is inexhaustible and inexhaustible,and has attracted widespread attention.According to statistics,marine energy accounts for more than 70%of the world's total energy and is considered to be one of the world's largest reserves of renewable energy.Marine energy mainly includes natural resources such as wave energy,tidal energy,ocean current energy,temperature difference energy,salinity difference energy,marine biomass energy,and seabed geothermal energy.As a kind of marine energy,wave energy is widely distributed and is the largest undeveloped renewable energy on the earth.If it can be fully developed and utilized,it will greatly alleviate the current energy shortage problem.This paper proposes a new type of buoyant pendulum wave energy converter,and uses the simulation software AQWA to simulate and analyze its hydrodynamic performance.The main research contents are as follows:First introduced the linear wave theory and the basic equations and boundary equations of the ideal fluid,and then explained the six degrees of freedom of the floating body movement,and then proposed a new type of buoyant pendulum wave energy converter,and its working principle Described and explained the resonance principle of the device.Based on this,a mathematical model of the pendulum's pitch motion is established,and according to the pitch motion equation,it can be seen that only by adjusting the upper and lower positions of the counterweight,the equivalent stiffness and equivalent inertia can be greatly adjusted,thereby adjusting the buoyancy pendulum's natural frequency.Then briefly introduce the current mainstream ocean engineering analysis software.According to the hydrodynamic parameters of the device to be studied in this article,I chose the software AQWA,which has both pre-processing and post-processing functions and has a very powerful comprehensive analysis capability.The threedimensional model was drawn using the drawing software UG,imported into AQWA Workbench,and the hydrodynamic model of the pendulum was established.Four sets of working conditions with different flooding depth positions and four sets of working conditions with different heights of the center of gravity are selected to explore the influence of flooding depth and height of the center of gravity on its hydrodynamic parameters.According to the calculation results,the law of changes in hydrodynamic parameters is analyzed.At the same time,it is concluded that by adjusting the height position of the counterweight,the natural frequency of the buoyancy pendulum can be greatly adjusted to make it resonate with waves and improve the power generation efficiency of the power generation device.Finally,the free damping oscillation test and resonance power generation test of the device were carried out.The free damping oscillation test proves that the selfvibration frequency of the buoyancy pendulum can be greatly changed by adjusting the height and position of the counterweight,and the resonance of the power generation device with different wave periods can be realized.And the test results are consistent with the simulation results.From the results of the resonance power generation test,the power generation efficiency of the model prototypes exceeded the 25% power generation efficiency index specified in the "13th Five-Year Plan".It proves that the device does have excellent performance of broadband and high-efficiency power generation,and has high application potential.