Fluid Structure Interaction Study On Suspending Axial-Flow Tidal Current Turbine

With the rapid development of society and economic, global energy demand has been growing rapidly. As the excessive consumption of traditional fossil energy and the resulting environmental pollution problem is becoming more and more serious, many countries in the world begin to do the research and application development on the renewable energy sources, such as ocean energy and other related energy. Among them,tidal current energy which is predictable and has high energy density and velocity stability has aroused people's more attention.In this thesis, we took new type axial-flow tidal current turbines as the object of the research, carried out a preliminary design to the structure sizes of the turbine and did Fluid Structure Interaction(FSI) analysis about the tidal current turbines and its rotors by combing the commercial software ANSYS Workbench and ANSYS CFX.The detailed researches were as follow:Firstly, according to the related theory and actual working condition, we carried out the project design about the tidal current power generation device. And the 3D model design software CATIA was used to establish the three dimensional model of the turbines,which contained the shape design of blades and ducts. 3D numerical simulations have been carried out using a CFD software to study the hydrodynamic performance of a ducted dual-rotor model with a shaft spacing of 1.8D(where D is the blade diameter) and the single-rotor model. Based on the previous study results, we established the experimental prototype, and carried out the physical model test, and the measurements verified the effectiveness of our CFD method.Secondly, the Fluid-solid interaction(FSI) method which based on the numerical simulation has been introduced in detail. The conceptions of One-way coupling and Two-way coupling have been defined. By using two different FSI methods, we calculated the static stresses of the tidal current turbines and the single-rotor in different cases.Finally, we conducted the wet model analysis for single-rotor model and got its inherent frequency and relating vibration modes in the water. Based on the model analysis results, we conducted the harmonic response analysis for the sing-rotor model,and it was verified whether the rotor can withstand the dynamic stress which caused by the structural resonance. Transient response analyses were carried out on the single-rotor model, and we analyzed the distributing characteristics of vibration, which under theaction of fluid exciting force, on the blade's dangerous surface from the perspective of time domain.