Numerical investigation of sand erosion rate in a horizontal axis wind turbine

Abstract

Renewable energy represents an important alternative solution for many energy problems nowadays and a tool for a healthier environment by reducing carbon footprints resulting from burning fossil fuels. However, more work needs to be done towards maximizing the energy produced from renewable energy methods and making sure that the infrastructure used stays in service for a longer duration. Sand erosion phenomena is responsible for the degradation of the wind turbine blades and hence the decrease in their performance and life. In the current research, a numerical study of both performance and sand erosion of a Small-Scale Horizontal Axis Wind Turbine (SS-HAWT) is carried out. This study introduces new sights of instantaneous and forecasted erosion rates within the blade of the wind turbines. Three-dimensional E216 airfoil blades of radius 0.5 m are established according to blade element momentum theory. Sand particles with different mass flow rates of 0.001, 0.002 and 0.003 kg/s and uniform diameters of 50, 100 and 200 μm have been selected as eroding particles under two different average air velocities of 8 m/s and 10 m/s. The results indicate that the performance of wind turbines is enhanced as the flow separation at the suction side is shifted to the trailing edge. Furthermore, the optimum tip speed ratio is about 5 at an air velocity of 8 m/s with a power coefficient of 0.432. In terms of erosion findings, V-shaped scars are reported near the leading edge of the blades. In addition, the instantaneous erosion rate grows exponentially with the tip speed ratio. Therefore, the yearly prediction of maximum erosion depth at the optimum operating conditions is obtained to be 5.7 mm/year in some spots of the turbine blades.