Fluid-Solid Interaction Analysis On Hydraulic Floating Wave Power Device

With the development of economy, the energy demand is increasing. The reducing of Traditional non-renewable energy reserves, not only has triggered the energy crisis, but also has caused a series of environmental problems. But using renewable energy is helpful to alleviate the energy crisis, optimize structure of the energy sources, and protect the environment. Many countries are committed to the development and utilization of renewable energy.Ocean energy is a kind of pollution-free green renewable energy which contains a variety of energy resources with rich reserves. Many countries focus their attentions on it. Wave energy, as the most widely distributed and least restrictive energy in ocean energy, has been extensively developed for power generation. But wave energy is very unstable, and marine environment is complex and changeful, so how to use the wave energy to generate electricity efficiently and permanently still remains to be improved.Hydraulic floating wave power device absorbs the wave energy by the floater, then the energy is transferred to the hydraulic system through the hydraulic cylinder connected with the floater to drive the hydraulic motor, at last the generator starts to work, and changes the energy into electricity. As the energy absorption device of the hydraulic floating wave power device, the floater is very important and its motion under the action of the wave directly affects the efficiency of power generation. The column of the power device is also noteworthy. The research about the floater and column in this paper is shown in following several aspects:Firstly, give a brief introduction to the working principle of the hydraulic floating wave power device and the sea condition of the place where the device is casted, then make a summary of the wave theory. Based on the wave theory, build three-dimensional numerical wave tank in the Fluent software and add source to the fluid governing equation to achieve the purpose of wave generating and wave absorbing. The numerical simulation results of linear waves and two-order stokes wave show that the numerical tank has a good effect on wave generating and wave absorbing.Secondly, analyze the velocity potential composition of the fluid around the floater and the stress condition of the floater. According to the theory of rigid body kinematics and Newtonian second law, build the equations of motion of the floater. Then couple the motion equation and the viscous fluid equations in the Fluent software on the basis of the three-dimensional numerical wave technology and grid technology. Analyze the stress condition and the movement of the floater with and without load in the wave environment, and get some important curves such as velocity-time curve displacement-time curve、force-time curve. The floater is directly connected with hydraulic cylinder, and the generating efficiency is proportional to the velocity of the floater. So generating efficiency-time curve can be got from the velocity-time curve.Finally, the interaction between column and wave is numerically simulated. In Ansys Workbench, one-way and two-way fluid-solid interaction(FSI) are carried to get the changes of the flow field near the device, as well as the deformation and the load change of the column. The simulation results provide a theoretical basis for the further optimization design.