Influence Of Typical Tropical Cyclone On Wake Flow And Load Of Yawed Wind Turbine

The southeast coastal area of China has a large amount of wind resources,and the development of offshore wind power technology can solve the large power load shortage in the coastal area.But at the same time,it will be affected by frequent tropical cyclones,which will affect the construction and operation of wind farms.Therefore,in order to reduce the fatigue load of wind turbine,it is of theoretical significance and engineering value to analyze the load of wind turbine during tropical cyclones.In this paper,a wind field model representing the mainstream direction of a tropical cyclone is constructed,and then the wake and load characteristics of a single wind turbine during yaw of a typical tropical cyclone are studied,and the change law of wake and load at different yaw are analyzed.(1)Taking NREL 5MW wind turbine as the research object,based on Open FOAM software,the wake velocity and turbulence characteristics of wind turbine at 20m/s uniform inflow are studied when the wind turbine is not yaw,yaw 15°,yaw 30° and yaw 45°.The velocity characteristics and turbulence characteristics of the wake of the wind turbine when the wind turbine is not yaw,yaw 15°,yaw 30° and yaw 45° are also discussed.It is found that the influence of tropical cyclone on wake velocity and turbulence intensity of wind turbine is far less than that of wind speed and turbulence intensity carried by tropical cyclone itself under the same yaw Angle,the relative quantity is small.For the same incoming flow,the wake velocity and turbulence intensity of the wind turbine decrease with the increase of yaw Angle,and the wake velocity and turbulence intensity are symmetrically distributed along the center line of the wind turbine without yaw,but asymmetrically distributed in yaw.(2)Taking NREL 5MW wind turbine as the research object,based on FAST software,the load of the wind turbine without yaw is studied at 20m/s with uniform incoming flow;During the typical effective tropical cyclone inflow,the load of the wind turbine without yawing;And in the typical destructive tropical cyclone incoming flow,the wind turbine rotor shutdown state of each load.It is found that the load amplitude fluctuation of the wind turbine increases greatly under the condition of efficient tropical cyclone inflow.The amplitude fluctuation of the pitching moment and flap-waving moment of the wind turbine shut down under the inflow condition of the destructive tropical cyclone is larger,while the amplitude fluctuation of the pendulum moment of the beneficial tropical cyclone is larger,and the thrust of the wind turbine is larger.The amplitude fluctuation of the thrust of the wind turbine is basically the same.(3)In the case of 20m/s uniform incoming flow and typical efficient tropical cyclone incoming flow,the load of wind turbine under the conditions of non-yaw to yaw 45° is studied.And the load of wind turbine before yaw to 40° yaw when the typical destructive tropical cyclone comes in.It is found that with the increase of yaw Angle,the load period and amplitude of uniform flow will increase.For typical effective tropical cyclone,the increase of yaw Angle has little effect on the load period and amplitude,little effect on the mean value of blade root shunt moment and lowspeed axial torque,and great effect on the mean value of flap-around moment and yaw moment.When the yaw of typical destructive tropical cyclone is less than 10°,the influence on the load of wind turbine is small,and with the increase of yaw Angle above 10°,the load of wind turbine is greatly increased.