| Recently,the depletion of fossil energy has been accelerated with the increasing energy consumption.Therefore,more and more researchers are committed to the development of new energy sources that can replace fossil energy.Among them,wind energy is one of the most promising new energy sources and becomes the hot topic.The utilization of wind energy resources mainly relies on the kinetic energy,captured by the wind turbines,convert into electrical energy.According to the direction of the rotation axis,the wind turbines can be divided into horizontal axis wind turbines and vertical axis wind turbinesCurrently,the horizontal axis wind turbines are rapidly developing and are suitable for large-scale grid-connected power stations,which mostly are megawatt-level large wind turbines.Relatively speaking,the development of vertical axis wind turbines is slow.However,it has some outstanding characteristics and advantages due to its special structural.First,the vertical axis wind turbines have simple structure,so it can receive wind in multiple directions.Besides,it can be installed directly on the ground,which is convenient for maintenance personnel to operate and control.What’s more,it has relatively constant force,which contributed to a long service life.Finally,the noise of vertical axis wind turbines is low.Vertical axis wind turbines are widely promoted and applied in cities,remote areas,agricultural and pastoral areas that are not suitable for large-scale grid-connected power generation.As we all know,the power of the vertical axis wind turbine is relying on the design of the airfoil profile of the wind turbine blade.Therefore,the profile design,modification and improvement of vertical axis wind turbine blades is an active area of research,and it is also a key link in increasing the power of vertical axis wind turbines that should not be underestimated.In this paper,the H-type vertical axis wind turbine is taken as the research object.The influence of different groove structures arranged at different positions on the aerodynamic performance of vertical axis wind turbine is studied by adopting the groove structure in passive flow technology.The wavy groove has three sizes arranged on the outer surface of the blade,0.1-0.4chord strength respectively.The curved grooves,Gurney grooves and Gurney flaps were arranged on the inner surface of the blade at a position of 0.9 chord length,respectively.Besides,the computational fluid dynamics method was used to analyze the aerodynamic performance of vertical axis wind turbine with different grooves,as a result ofthe complicated unsteady flow conditions of vertical axis wind turbine blades,and the influence of grooves on the gas flow was observed.And airfoil aerodynamic effect is the best arrangement of the side groove structure wind turbine airfoil and back arrangement best pneumatic groove structure effect of wind turbine and the original airfoil wind machine,wind and solar energy experimental base in Inner Mongolia university of technology in wind tunnel experiment,and explores the vertical axis wind turbines with groove structure optimum installation Angle.The results show that the wind tunnel experiment verifies the results of the simulation calculation,and proves that the wind turbine with the changed profile has a positive effect on improving the aerodynamics.Within a certain range of blade tip ratio,the wind energy utilization rate of a wind generator with one corrugated groove and a wind generator with arc-shaped grooves can be improved.The wind turbine with 1 wavy groove can increase the wind energy utilization rate by 13.76% at low tip ratio,and the tangential force of the single blade increases significantly in the downstream area.The wind turbine with curved grooves can increase the maximum wind energy utilization rate by 14.60% at high tip speed ratio,and the tangential force of the single blade increases significantly in the upstream region.The two modified blades can improve the flow separation and improve the aerodynamic performance of the vertical axis wind turbine.The optimal installation Angle of the vertical axis wind turbine with different grooves is the same as that of the original airfoil vertical axis wind turbine.It can be found that the grooves can effectively improve the lift coefficient of the airfoil in the area where the Angle of attack is from 0° to 16°the drag-reduction effect is better for the airfoil with curved grooves.The maximum drag-reduction rate can reach45.62%.In a small Angle of attack range,a wavy grooves would not reduce drag,while a larger Angle of attack would lead to a stronger separation zone on the upper surface of the airfoil.The drag-reduction effect of the wavy grooves would also increase with an increasing Angle of attack. |
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