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In Northwest China, wind resources are especially abundant, but this area is also seriously affected by sandy environments, so any wind turbines in this area are definitely affected by the sand-wind flow. Therefore, the shear stress transport k-ω turbulence model and discrete phase model are both used for the simulation of an S809 airfoil to study the influence of sandy environments on the aerodynamic performance. Based on this, the modified blade element momentum theory will be used to design wind turbines that can operate in both clean air and sandy environments and study the influence of sandy environments on wind turbine performance. The results show that the influence of the sand-wind environment on the aerodynamic performance of the airfoil is as follows. In the particle diameter range of 5 to 30 μm, as the particle diameter increases, the lift coefficient decreases, and the drag coefficient increases. However, in the particle diameter range of 30 to 100 μm, the change is just the opposite. At the same time, as the increase of particle mass concentration, the lift coefficient of the airfoil decreases, and the drag coefficient significantly increases. Also with the increase of equivalent density, the change is just the opposite. Moreover, the influence of sandy environments on the performance of wind turbines is found to be as follows. At low wind speeds, the power output of the sandy turbine is greater than that of the clean turbine when they run in a sandy environment. Also, it is found that whether wind turbines run at high or low wind speeds, the thrust of sandy turbine is less than that of clean turbine when they run in sandy environments.

No abstract

Field experiments are carried out to investigate the fluctuation characteristics of pressure on wind turbine blade surface in real operating environments. The tested wind turbine positioned pressure tapes along the blade span to obtain the dynamic pressure of seven airfoil sections over six rotation periods, and analyzed its time-domain, frequency domain, and standard deviation. The results show that the pressure on blade surface presents highly unsteady characteristics, and rotation of the wind turbine is one of the main factors that causes pressure fluctuations on the blade surface. The standard deviation of pressure near the leading edge of each airfoil section is relatively larger, indicating that the leading edge is the most sensitive to field wind conditions. Compared with the pressure surface, the blade suction surface contributes more to wind turbine power fluctuation and is more sensitive to various unsteady sources. Moreover, the standard deviation of the pressure on the blade pressure surface is largest at the tip, and the standard deviation of the pressure on the blade suction surface is clearly divided into two regions along the chord direction with different scales at different spanwise sections.