Numerical study of high lift devices to improve airfoil aerodynamic performance

Abstract

ABSTRACT High Lift Devices (HLD) are frequently used flow control devices able to increase the amount of lift generated by a wind turbine blade. The current paper presents a parametric study on the aerodynamic performance of a DU91W(2)250 airfoil with a stationary element placed at the trailing edge. The aerodynamic analysis of these devices is performed using computational fluid dynamics (CFD) based on a 2D Reynolds-averaged Navier-Stokes (RANS) K-ω Shear Stress Transport (SST) turbulence model under the effect of various high Reynolds numbers. The influence of these elements is measured for different angles of attack, lengths and tilt angles. In addition, the novel Cell-set (CS) modeling method has been compared to a fully meshed HLD model to test the reusable cell approach. Numerical results have shown that, for all 10° tilted devices at positive AoAs, high lift values are reached for HLD lengths 0.187c and 0.3c. Particularly for a 0.187c device length, lift experiences a significant enhancement at AoA 7.5°. The impact of HLDs decreases at AoAs between −2.5° and 2.5°and even underperform the baseline airfoil when studying 0.015c devices. Besides, the CS method was validated as a precise modeling tool as a maximum error of 1.93% was determined.