Research On Power Generation And Stability Of Dielectric Elastomer Driven By Oscillating Water Column

Most of the surface of the earth is covered by the ocean,which are rich in energy resources.As an important component of ocean energy,wave is a kind of high-quality renewable energy.The oscillating water column wave energy device collects energy from the ocean and converts it into electrical energy.Its power generation unit is exposed to the humid environment for a long time,which is prone to corrosion damage,resulting in short service life and difficult maintenance.In this paper,the power generation mode is changed based on the traditional oscillating water column wave energy power generation device,the traditional air turbine generator is replaced by a dielectric elastomer generator,then the structure of the device is simplified and the life of the power generation system is extended.The main research contents are as follows:(1)The dynamic model of oscillating water column is established based on the potential flow theory,and the velocity potential expression by the Green function method is grasped,the pressure at the position of the front wall inside the air chamber device of the oscillating water column and the pressure at various underwater locations is obtained.The hyperelastic model of dielectric elastomer and the interaction model between pressure and film are established to solve the pressure inside the air chamber,the displacement of water column and the deformation of dielectric elastomer film.The ABAQUS finite element software is used to simulate and analyze the deformation of the dielectric elastomer film.After comparison with the theoretical results,it is found that there is little difference between the two,indicating that theoretical calculation model can simulate the deformation of the dielectric elastomer film driven by the oscillating water column.Through the simulation on the deformation of the film after pre-stretching,it is concluded that under the same pressure,the more pre-stretching,the less the deformation of the film.(2)The variation of capacitance with wave parameters(including the period cycle and amplitude),oscillating water column device parameters(including the depth of water and front wall draft)and dielectric elastomer film parameters(including the radius and thickness)during the deformation process of dielectric elastomer film driven by oscillating water column is studied.The effects of the above parameters on the output energy of the dielectric elastomer film driven by the oscillating water column device are discussed.After comparing the output energy of three energy collection cycles of dielectric elastomer,the optimal parameters and the maximum output energy are determined.It is concluded that the maximum energy can be obtained through the constant electric field energy cycle.Moreover,when the pre-stretching is applied to the film,the output energy of the dielectric elastomer film decreases as the pre-stretching increases.(3)The stability of the dielectric elastomer film driven by oscillating water column during deformation is investigated.Based on the relative permittivity related to temperature and the free energy model of thermoelastic dielectric elastomer is established.Equations in unstable state at the condition of tensile loss,electric breakdown,dielectric instability and tensile fracture failure modes when film deformation are calculated and the effect of temperature on each failure mode are analyzed.It is found that the nominal stress and the nominal electric field will be increased when the temperature increases.The stable working area of dielectric elastomer film is defined and the influence of temperature and electrostrictive coefficient on the stable working area is studied.It is concluded that the stable working area of dielectric elastomer film becomes larger when the temperature increases or the electrostrictive coefficient decreases.It is also proved that the dielectric elastomer film deformation driven by oscillating water column will not fail in any mode under the given parameters.