Study On Oscillating Hydrofoil Tidal Energy Generator Applied Liquid Metal Magnetohydrodynamics

With the environment deteriorating and the human demand for energy increasing continually,people pay more attention to the development technology of renewable energy.As a new type of marine energy,tidal current has the advantages of high energy density and convenient development.In current tidal current power generation devices,excitation generators are often used for power generation.Gearbox transmission or hydraulic transmission is required to meet the requirements of high-speed generators for system transmission,which enhances the complexity of the device and the difficulty of maintenance.Therefore,this paper proposes to use liquid metal magnetic fluid power generation to replace the traditional power generation,and to study the performance of this new tidal energy power generation system.Firstly,the model of system is established and the mathematical model of the system is established according to the airfoil theory and liquid metal magnetic fluid power generation theory.The relationship between power generation parameters,overall power generation efficiency and seawater flow rate,hydrofoil airfoil parameters,pitch motion parameters are determined.Then,the Simulink simulation model is established by using Matlab.The reference standard for measuring the lift performance and motion performance of the hydrofoil by the lift coefficient and the maximum heave height of the hydrofoil and the reference standard for measuring the electrical performance of the system by the power generation and power generation efficiency is decided.Secondly,I study the hydrodynamic performance and lift performance of the hydrofoil by simulating the Simulink simulation model.The results show that when the hydrofoil pitching motion is designed to be sinusoidal motion,the heave motion of the hydrofoil is also sinusoidal motion that has the same frequency and has a slight motion lag than the pitching motion.Within a certain angle of attack,the angle of attack is larger,the lift coefficient is larger.The change of the pitch amplitude of the hydrofoil has a great influence on the lift performance of the hydrofoil.The hydrofoil with low pitch frequency and flow velocity have a great influence on the hydrofoil’s motion performance.Finally,the electrical performance of the oscillating hydrofoil tidal energy generator system applied liquid metal magnetohydrodynamics generator is analyzed.The research results show that the liquid metal magnetic fluid power generation mode has the characteristics of large current and small voltage.When the hydrofoil pitching motion is sinusoidal motion,the system emits alternating current with the same AC frequency as the pitch frequency and the final power generation can reach 2-3kW.The increase of the pitch amplitude has a signi:ficant effect on the power generation and efficiency.When the pitch amplitude is larger,the lifting effect is more obvious.Reducing the airfoil chord length can increase the power generation and efficiency effectively.When the chord length is small,increasing the thickness of the airfoil has a better effect on increasing the power generation.The power generation system can effectively increase the power generation in the tidal current with a higher velocity,but will reduce the overall power generation efficiency.