The Optimization And Numerical Analysis Of The Axial Tidal Current Turbine

The tidal current turbine is the equipment which extracts the energy from the tidal current. The tidal current turbine is direct put into the current stream which is different from the traditional tidal turbine, for the low cost of the energy generation.Nowadays, the solving the global warming problem has become the hot topic of the renewable energy research. Compared with the wind energy, the tidal energy is more predictable and more energy density. How to efficiently transform the energy from the tidal to electricity is the key of the design of the tidal current turbine. A series of the hydrofoils are the base of the tidal current turbine design. At the other hand, the accuracy of method used to predict the characteristic of the tidal current turbine is important to design a high efficient tidal current turbine.In this paper, the airfoil dynamics forecasting software XFoil is used and the accuracy of the predicted results are verified. Combined with MATLAB platform, we use embedded programming to define the parameter of NACA63-815. Then, the convergence of geometry and aerodynamic of the parameter hydrofoil is confirmed.And next, the particle swarm algorithm optimization method is used to search the optimize function solution which targets the dynamic characteristics of the hydrofoil at different attack angle. The comparison between the original hydrofoil and the optimized hydrofoil shown that lift and lift-to-drag coefficient of the optimized hydrofoil are significantly enhance ranging from 0° to 20 °, which verify optimization progress.Based on blade element momentum theory method(BEM), using XFoil software provides real-time kinetic parameters of blade section hydrofoil to solve radial velocity coefficient and axial velocity coefficient. The local Reynolds number is involved to describing the Reynolds effect on the hydrofoil. The results of the Reynolds number correction BEM model are compared with the commercial software,which show that the accuracy of the Reynolds number correction BEM model prediction is much better. In the high tip speed ratio, the error of the Reynolds number correction BEM model is 7%, while the commercial software is 50%.With the optimized hydrofoil, the turbine blade geometry is redesign. Based on the XFoil code and the Reynolds number correction BEM model, the optimize function combining with the tidal current turbine power coefficient at different tip speed ratio(TSR) is optimized by the MATLAB function. After optimization, the performance characteristics of the tidal current turbine at different tip speed ratio(TSR) are compared with the original tidal current turbines. Except for TSR = 6, the performance of the tidal current turbine have increased significantly.Using UG to rebuild the tidal current turbine 3D model and meshing of the tidal current turbine is conducted by ICEM to build the structured grids of the fluid domain.The SST turbulence model is applied to tidal current turbine numerical prediction.And then, the distributions of velocity field and pressure field of the fluid domain are analyzed.