Numerical Simulation And Experimental Study Of Double Helical Rotors Type Wave Energy Converter

As one of the most abundant energy in ocean resources,wave energy is not only easy to utilize,but also environmental and renewable.In the current social context of energy crisis,wave energy development and utilization is important for social development,economic prosperity and border building energy supply.In this thesis,study works have been done from theoretical analysis,simulation to model test about the double helical rotors type wave energy converter apparatus.The main contents and conclusions are as follows.(1)On the background of energy use and social development,the present paper describes the research significance and analyzes the abroad and domestic research status of wave energy converter from the working principle and characteristics of all kinds of wave energy devices.(2)Based on the three-dimensional potential flow theory,analyzes the energy conversion principle of the device,the equations of the water dynamic forces on the flow pipe and impeller blades are thereby concluded,and then provides preference values of control items such as related physical parameters,boundary conditions to the three-dimensional simulation of the device.(3)The simulation results of wave energy device show that: When the flow velocity is small,the torque of 12 mm blade thickness is slightly larger than the other two cases,in other words,the change of blade thickness has a slight effect on the device efficiency;and when the flow velocity is large,the influence of the blade thickness on the torque are apparent,as the blade thickness is8 mm the torque is minimum,while blade thickness is 4mm,the torque is greater than the other two cases;At different flow velocities,with the increase of the blade radial length,the torque decreases;At different flow velocities,with the increase in axial length,the torque lifts first and then decreases,and pinks at about 60 mm axial length;The impact of torque margin gap is quite obvious,as the greater the gap,the smaller the torque,the larger the leakage losses,and the lower the device efficiency;With the increase of the blade number,the torque lifts first and then decreases,and reaches a maximum at about 15 blades;Additional constriction can effectively change the flow state to get a larger torque,and to enhance the system efficiency,the torque reaches a maximum at 15?tilt angle;(4)Experiments of device model is taken in the wave flume,change the wave parametersand get the output parameters of wave energy device model,and analyze the impact of waves on device performance,then provide proposals for issues that arise from the experiment.According to the experiments,when the water depth is 40 cm,the rotation speed is fastest,and the rotation speed will decrease while the wave period increases.