Impeller Performance Study Of Multi-stage Energy-Capable Tidal Power Generation Device

Amidst whimsical international politics and economic trends,many disputes involve energy competition and the problems of interest brought by the energy industry.Therefore,the development in the energy field is always an important topic that cannot be ignored in the international environment.The exploitation and utilization of land resources are gradually saturated,and the ocean,which occupies more than 70% of the earth's surface area,has become the focus of discussion and engagement.Marine resources,especially marine renewable energy,have become the hot topic among researchers in the current energy discourse system,and among them,the development and exploitation of tidal current power has become the main stream.The research on tidal current energy in various energy great powers,including China,has begun to enter the blowout stage.A variety of equipment forms and transmission patterns emerge in an endless stream,causing full discussion in the scientific research and academic circles,but they are still one step away from mature large-scale applications.In such a disentangled and complex environment,it is inevitable to study the design,optimization and demonstration application of a new type tidal current energy utilization device.Therefore,how to make breakthroughs in current tidal power exploitation to further promote the performance development of tidal current energy utilization devices has become the layout concept and key issue of this graduation thesis.This paper takes the improvement of tidal current capture device and single unit performance of tidal power generation equipment at present as the objective,and a multi stage impeller tidal current power generator is proposed by increasing impeller stages and making reference to the design concept,simulation and practical experience of traditional hydroturbines.Moreover,micro and macroscopic studies are carried out on each factor of the impellers,and the device feasibility and effectiveness are verified through software simulation and prototype experiment.First of all,in order to fill in the blanks of current literature review and market research,not only the research history of tidal power generation device is introduced,but also the latest research results in the field of tidal energy at home and abroad in recent years are described.It is pointed out that the research of tidal power turbine is in the climbing stage,and further research exploration in this field is required;Secondly,to provide complete logic to support the design and optimization of the impellers,the basic theories and methods of impeller design involved in the design field of tidal turbines are introduced,including airfoil theory,momentum blade-element theory and,furthermore,the analysis theory of blade ultimate performance deducted by integral calculation;the numerical values of the force and energy superposition of turbines under the combined effect of waves and currents are calculated.In the blade ultimate performance analysis,the turbine power performance,torque performance,lift performance and thrust performance are included.On the basis of the previous research,the paper makes a more in-depth and detailed description,and adds more applicable calculation and derivation with more extendibility,which can provide theoretical support for the following airfoil optimization,blade design and impeller design;Furthermore,a detailed introduction of the new type multi stage impeller tidal current power generator is made,ranging from overall structure,airfoil optimization,blade structure design,multi stage impeller structure design to fixed pile design.The structure parameters of main components are designed and determined through methods including classical theoretical calculation,computational fluid dynamics analysis and finite element numerical simulation,and the complete equipment is made in the end.In the previous process,the influence of the curvature of the trailing edge of the airfoil on its hydrodynamic performance is introduced,and the bending angles of the blades are set to the optimal 15°.In the next step,the blade numbers and impeller stage numbers are studied,and the five-blade three-stage impellers are determined.Later on,the optimal distance between each impeller stage is determined and the impeller optimization design is finished;And then,hydrodynamic analysis of the impellers designed and finished in the previous text is conducted,and the Fluent fluid simulation module in ANSYSWorkbench is used for model building,mesh generation,solution and result processing.The transient rotating region speed change,calculation region speed change and pressure distribution in different sections of the multi stage impeller in different steps are demonstrated,the simulation performance of the new type impeller is analyzed,and the correctness and the effectiveness of the design purpose are verified;In the end,the correctness of the optimization design described above is verified through designing airfoil optimization experiment,blade optimization experiment,multi stage impeller prototype experiment and the marine experiment of the complete machine of the multi stage tidal current power generator,improving the credibility of the research results of this paper.In addition,a reference for the experimental methods and process designs in the field of tidal current power generation is provided through the platform construction,electrical design,data acquisition and other methods during the experiment.