| As global energy consumption continues to increase,people are paying more and more attention to the use of renewable energy.Tidal energy,as a clean energy source,has gradually become one of the trends in the development of world energy diversity due to its large reserves and convenient acquisition.The water turbine is the main tool for developing tidal energy,and the vertical axis tidal energy water turbine is increasingly receiving attention and research due to its high adaptability.Compared to a single water turbine,a multi-rotor water turbine arranged simultaneously can generate greater energy harvesting effects.Therefore,studying the hydrodynamic characteristics of multi-rotor water turbines is very important.In this paper,the hydrodynamic performance of vertical axis tidal energy water turbines under different operating conditions was studied by simulating and analyzing a representative double-rotor vertical axis water turbine.The impeller is the key component for energy capture in water turbines.In this paper,using two water turbines as representatives,we firstly studied the energy harvesting efficiency and load variation of a double-rotor vertical axis water turbine under different spacing and relative rotation directions.Furthermore,the interference mechanism between the rotors of the vertical axis water turbine was revealed by combining the flow field analysis.Subsequently,numerical simulations were carried out to investigate the energy harvesting of a double-rotor vertical axis water turbine in a wave-flow coupling environment.The performance of the double-rotor vertical axis water turbine was analyzed under wave conditions,and the load on the blades and turbine were monitored to summarize the impact of waves on the water turbine.Experimental studies were also conducted on the double-rotor water turbine in uniform flow and wave-flow coupling environments.The power output of the double-rotor water turbine under uniform flow and wave-flow coupling conditions was monitored by torque sensors to further verify the conclusions of the numerical simulations.Finally,with regards to the development trend of tidal energy generation devices,this paper combines the double-rotor vertical axis water turbine with a floating platform,and studies the power output and load characteristics of the double-rotor vertical axis water turbine in typical working conditions under three types of motion states: heave,pitch and roll,in a steady flow.Subsequently,in a wave-flow coupling environment,we focus on the influence of parameters such as the turbine spacing,turbine rotation direction,and speed ratio of the water turbine on the motion of the floating platform and mooring force.In addition,we also studied the motion characteristics of the multi-rotor floating platform under different wave parameters.By performing numerical simulations on the scheme that combines the double-rotor vertical axis water turbine with the floating platform,we obtained the performance characteristics of the multi-rotor floating platform,which can provide important reference for the design,optimization,and operation of tidal energy generation devices in practical engineering. |
PDF Full Text Request