Dynamic stall characteristics of wind turbine airfoil in sand-wind environment

Although the traditional dynamic stall has been well studied, the effect of sand particle on dynamic stall char-acteristics is seldom considered in the previous studies. Therefore, a research about dynamic stall of the S809 airfoil is accomplished under a sand-wind environment. The unsteady CFD method and the discrete phase model (DPM) are adopted in this research to simulate the dynamic stall characteristic of the S809 airfoil. The influence of different sand particle diameters and different particle concentrations on airfoil dynamic stall characteristics is studied respectively. The simulated results indicate that the maximum lift coefficient and drag coefficient with particle diameter of 10 mu m decrease about 2.18% and 2.52% respectively compared with that of the clear air. Meanwhile, the maximum lift coefficient decreases about 6.93% for the case of particle concentration with 62.6 g/m3. The simulated results also indicate that the lift coefficient and drag coefficient decreasing are enlarged with particle concentration increasing. This tendency indicated that the efficiency of a wind turbine would be reduced in sand storm weather.