Research On Structural Optimization And Piezoelectric Generation Of 3D Offshore Oscillating Water Column Model

The traditional research structure of oscillating water column type Wave power generation devices mainly uses air chamber to collect wave kinetic energy which can be converted into air kinetic energy to drive turbine generator to output electric energy.The structures of mechanical equipments are complex,and they are easy to be corroded by seawater which resulted in short service life.So,They are not suitable to provide continuous and effective energy supply for marine network sensors.Based on the research of traditional OWC Wave power generation,this paper proposes an offshore oscillating water column Wave power generation device based on piezoelectric ceramic wafer to output electric energy.The oscillating water column air chamber collects wave energy,and converts wave kinetic energy into air kinetic energy to drive the piezoelectric ceramic wafer to deform and generate electricity.The output electric energy directly supplies power for small devices such as ocean buoy lamps and wireless sensors.The piezoelectric vibrator is forced by the floppy drive action of air to avoid breaking due to impact of rigid contact.The structures of new energy conversion are simple and they could continuously supply power to devices such as marine wireless sensors by wave energy.Study on the Primary Energy Transfer Device of Wave Energy(oscillating water column wave energy collection).Computational Fluid Dynamics(CFD)software is used to divide the three-dimensional flume model into mixed grids,FLUENT software is used to simulate the wave generation by open channel method,and VOF model is used to monitor the hydrodynamic process in the flume.The influence of factors such as water depth and incident wave height of the front wall on the output energy of the gas chamber was studied.Four OWC gas chamber structural models with symmetrical and asymmetrical front and rear walls of square and cylindrical shape are compared and analyzed.The gas-liquid two-phase fluid mixture were solved by Navier-Stokes equation,and the highest output pressure of 2172Pa is obtained when the square gas chamber with asymmetrical front and rear walls is in the suction state of the gas chamber.A single air chamber,a series double air chamber and a series three air chambers are studied to collect the air mass flow output by a Wave period.Considering the equipment construction and the output efficiency,the series double air chamber are determined as the optimal output model,and the series double air chamber combined with the piezoelectric ceramic wafer are designed as the structural model of the oscillating water column type piezoelectric power generation device.The research on The Secondary Energy Transfer Device of Wave Energy(wave energy driven piezoelectric power generation),summarizes the excitation modes of piezoelectric ceramic wafers,solves four types of piezoelectric equations by combining mechanical conditions and boundary conditions,and theoretically analyzes the piezoelectric wafers with fixed boundary conditions to obtain their central point deformation values.The APDL software is applied to write the simulation analysis process of piezoelectric wafer.Under the fixed support boundary condition,variable load force is applied to the circular piezoelectric vibrator.The matrix conversion formula is adopted to convert the basic parameters of the four piezoelectric materials into computer data recognizable by APDL,The output power of PZT-5A piezoelectric material is 1.1V.Taking PZT-5A as the research object,the factors affecting energy output,such as the thickness of piezoelectric wafer,the number of stacked layers and metal substrate materials,is simulated and analyzed.The results show that the output voltage is 1.36V when the thickness of the piezoelectric wafer is 1.2mm and the number of stacked layers is 5.The output energy of aluminum(Al)substrate material is relatively obvious,which is 5.5 times that of single crystal piezoelectric sheet.The excitation experiment was used to simulate the impact of air flow on the piezoelectric wafer.The results of simulating the output energy of the piezoelectric wafer were verified.The influence of excitation frequency and matching impedance on the output voltage was measured.The results showed that the output voltage of the piezoelectric vibrator with larger substrate diameter also increased,and the output energy was relatively more stable under the influence of external conditions.