Simulation Analysis And Optimization Of Offshore Oscillating Water Column Wave Energy Gathering Chamber

Wave energy, as a large and widely distributed clean energy, has high exploiting value. It can convert wave energy into other forms of energy, usually electric energy with various energy conversion device. The oscillating water column (OWC) wave energy converter is widely used in the world. Because it is important of the form and size of oscillating water column gas chamber for the energy conversion efficiency,the related parameters were optimized with the computational fluid dynamics (CFD)method for the offshore oscillating water column wave, It included the integration optimization of different meshing methods and air chamber simulation methods which elaborated the oscillation water column gas chamber parameters and CFD analysis process.The structured grid or mixed mesh is designed with VOF model in the ICEM CFD, dynamic mesh, porous media and user defined function (UDF) function of the FLUENT software. The wave elimination technology are used in 2D and 3D numerical wave tank to create respectively with the water quality point wave and push plate wave in open channel. The sinks created by the push plate wave method are applied to simulate the oscillating water column in the gas chamber. It was optimized for the draft depth and width of the front wall and the width of the chamber with the 2D model simulated in different periodic linear wavesBased on the results of 2D analysis, It was optimized about the height and the outlet size of the offshore oscillating water column with 3D model. The size of the single-chamber model is determined according to the optimal results. More than one air chamber is connect in series to design double or three gas chamber structure. The relationship is verified between wave and air chamber based on the analyzing results of the liquid level and pressure in each chamber and the velocity vector cloud and volume fraction cloud.The analysis results show that : The numerical wave tank can optimize the parameters of oscillating water column which is modeled with wave-making and elimination function using FLUENT software. The conversion efficiency reach peak when the offshore oscillating column resonated in the chamber (the wave period is about 3.75 s?T?4.25s). At the same time the amplitude of the liquid level in the chamber increases when the sizes decrease of the draft depth, the thickness of the front wall and the width of the chamber. It was obviously that the width of the chamber affects the energy conversion power. The efficiency will improve when two or more offshore air chambers connect in series. The pressure in the frount chamber is greater than the following ones. The oscillating water column will runs in the form of 'one up and one drop' if the appropriate U-shaped chambers are set up. At the same time,the positive and negative pressure produce in the former and the rear chamber. And the relative pressure will increase significantly.