Study On Hydrodynamic Performance Of A New Floating Wave Energy Power Generation Device

As the world economy continues to develop and traditional energy sources become increasingly scarce,mankind is gradually turning its attention to the vast field of ocean energy.The oscillating float type wave energy generation device is one of the hot spots in the research of marine energy generation devices because of its high efficiency and flexible arrangement.This thesis proposes a new floating wave energy conversion scheme,completes the structural design of the device,and establishes the numerical model of its motion response,and investigates its hydrodynamic performance from both theoretical analysis and numerical simulation.The main research contents are as follows:(1)Design and theoretical analysis of a new floating wave energy generation device.In this thesis,a new type of floating wave energy generation device is proposed.The design principle,structural composition and energy conversion mechanism of the new type of floating wave energy generation device are analysed in detail,and the kinematic and dynamic characteristics of the device are mathematically modelled and theoretically studied.(2)Research on the hydrodynamic characteristics of the power generation device by wave parameters.A non-stationary RANS computational fluid dynamics based approach is used to establish a numerical pool using STAR-CCM+ based on the boundary wave generation method and the damped wave dissipation method,and to compare the wave generation with the theoretical values to verify the accuracy of the numerical pool wave generation.It is found that appropriate adjustment of wave period and wave height can help to increase the output power of the device,but in practical engineering,the period cannot be reduced indefinitely,which will cause the power generation device to vibrate too fast and easily cause energy impact and waste,and the wave height cannot be increased indefinitely,which will cause the wave steepness to be too steep and cause the phenomenon of upwelling.(3)Study of the influence of structural parameters on the hydrodynamic characteristics of power generation units.The study investigates the parametric patterns of the motion response and output power of the device under the same input wave conditions and different structural parameters.Considering that the device will generate other degrees of freedom of motion under wave action,the presence of damping plates will change the flow field where the floats are located,thus increasing the stability of the device,so the study of the operation of the device with or without the addition of damping plates is carried out;the study of the performance of the device for changing different numbers of rotating blades.The results show that an appropriate increase in the number of blades allows the vortex fan to produce a greater rotational torque,and that the overall performance of the five-bladed vortex fan is superior in terms of overall device cost,vortex fan operation and power generation efficiency.(4)Numerical simulation study of the hydrodynamic characteristics of an array-based power generator.The effect of the arrangement of the devices on the hydrodynamic coefficient of the array,the response of the device motion and the power output is investigated and this leads to recommendations for the configuration of the device array.The wave power output of the different arrays fluctuates with the wave cycle,with more significant fluctuations in the floats in front of each array at the waveward end and less so in the floats at the rear.The overall performance of the triangular array is better than the other two array types for a certain spacing between the three types of arrays,and the overall energy conversion efficiency can be improved by a reasonable arrangement of the power generation devices.