Impact of Vortex Generators on Archimedes Spiral Wind Turbine

Abstract

This research presents a novel method for studying the effect of vortex generators on an Archimedes Spiral Wind Turbine (ASWT), demonstrating improvements in power output and efficiency compared to conventional designs. While many forms of horizontal-axis wind turbines exist, the Archimedes spiral wind turbine is particularly efficient for small-scale applications and performs well at low wind speeds. The design features three blades characterized by a uniform spiral growth. Vortex generators (VG) are small devices that enhance flow attachment by creating vortices. This study explores the potential benefits of integrating vortex generators with ASWTs to enhance Horizontal Axis Wind Turbine (HAWT) systems and applications. Computational Fluid Dynamics (CFD) simulations were conducted to assess and compare the effects of these generators on the ASWT. The CFD analysis was performed using the Reynolds-Averaged Navier-Stokes (RANS) equations through the FLUENT package of ANSYS. Initial results showed that large vortex generators negatively impacted performance, reducing efficiency compared to both conventional and small vortex generators because the large vortex generators introduced unwanted drag. Conversely, the inclusion of small vortex generators increased power output by 3.3%, 2.4%, 0.5%, 1.7%, and 4.7% at Tip Speed Ratios (TSR) of 1.0, 1.5, 2.0, 2.5, and 3, respectively. Subsequently, an experiment was conducted to assess the effect of VGs on both modified and conventional systems. The results measured at frequencies of 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 Hz, indicated changes in output of -12.5%, -12.5%, 0%, 6.1%, 7.0%, 0.6%, 2.3%, 0.2%, 4.2%, 4.2% respectively. Overall, it was concluded that power output is enhanced at higher TSRs, confirming that vortex generators improve the performance of the ASWT.