Hydrodynamic Performance Research Of A Single Float Type Wave Power Conversion Device

With the advantages of large reserves, no-pollution and cyclic utilization, wave energy is becoming one of the hot spots in the domestic and international ocean energy research field. China owns long coastline, the wave energy reserves is quite abundant and huge potential for the development and utilization in the future. Research and design the wave energy converter that suitable for China’s particular parts of the ocean is extremely important to alleviate the energy crisis and environmental pressure. Single float type wave power generation device is successfully designed based on the heave motion of marine structures. It owns the advantages of simple structure, excellent adaptability, high conversion efficiency and good reliability. In order to develop the Single float type wave power generation device practically, both physical model experiment and numerical simulation are developed to study the wave energy converting systemically.This paper introduces the related knowledge of Airy wave theory, and then theoretical analysis of the characteristics of the wave movement. Based on those analyses, this paper specially develops the method to calculate the wave energy of the wave front.The main research works are listed as follows:(1) Hydrodynamic calculation and analysis The principle of wave energy conversion device (WEC) is to use relative motion between objects, theoretical analysis and calculation of vertical wave exciting force is deduced. And vertical cylinder is chose as wave energy capture device. Then we do analysis the hydrodynamic performance about the cylinder plasmodium:frustum of a cone shaped floating body, pour frustum of a cone shaped floating body and vertical placed cylinder in time domain area. And the numerical results of response shows good agreement with the model test results.(2) Model test This paper designed a model of WEC that based on the heaving movement of floating body, and also designed corresponding energy storage, controlling unit, hydraulic plumbing system and the match relations between hydraulic cylinder, hydraulic motor, and generator. Based on those, model test is carried out under regular waves in the laboratory. The hydrodynamic performances of wave energy power generation device are tested under different wave heights, wave frequencies and different initial drafts. And then the relations between those factors and the output power are studied.(3) Experimental results and analysis Through researching and analysis, the main conclusions of this paper are obtained as follows:1) The generation capacity of the wave energy generation increases with the incident wave height.2) Near the natural frequency of the device, device easily occurred resonance phenomenon, and at this condition wave energy power generation gets maximum result.3) Wave energy conversion efficiency changing trend is more complex, for this device in the incident wave height of0.36m, wave frequency is0.4Hz, wave energy conversion efficiency maximum22%.This paper comprehensive use of numerical simulation and model test method, research the device generating capacity and conversion efficiency of the main factors:initial draft, wave height, wave frequency, and gives optimal incident wave elements. The model test gives the certain reference value and basis for practical engineering application.