Calculation of the Water Droplets Local Collection Efficiency on the Wind Turbines Blade

Abstract

Wind turbines operating in cold climate are susceptible to icing events. In order to gain a better understanding of the blade icing, the water droplets local collection efficiency affected by different factors was investigated. First, the water droplets conservation equations which are based on the fluent user-defined scalar (UDS) were introduced. Second, the Eulerian method was validated. Two test cases indicate that the developed method is effective. Then, the local collection efficiency on the S809 airfoil was studied. Results show that as the angle of attack (AOA) increases, the water droplets impingement region moves toward the airfoil lower surface and the maximum local collection efficiency decreases. The local collection efficiency and the impingement region increase with the water droplets diameter and the air flow velocity but decrease with the airfoil chord length. Finally, the local collection efficiency affected by the three-dimensional (3D) effect was studied. Results show that the maximum local collection efficiency in the blade tip region decreases up to 96.29% due to the 3D effect.