EXPERIMENTAL INVESTIGATION OF THE ENERGY CHARACTERISTICS OF A VERTICAL-AXIS WIND TURBINE WITH A WIND FLOW CONCENTRATOR IN A WIND TUNNEL

Abstract

This paper presents the results of an experimental study on the efficiency of a vertical-axis wind turbine equipped with a stationary aerodynamic wind flow concentrator. The relevance of this work is driven by the need to improve the energy performance of autonomous power generation systems in low-potential wind flow conditions (3–5 m/s). The primary objective of the research is the experimental evaluation of the improvement in the starting and operational characteristics of such a wind turbine. The research methodology is based on a comparative analysis of the characteristics of a baseline Savonius rotor and a modified wind generation system utilizing confuser-type guide vanes. Experimental investigations were conducted in a subsonic wind tunnel using a PMG-20 permanent magnet synchronous generator. The operating mode of the wind turbine was investigated under an active electrical load of 230 Ohms, simulating the power supply for low-power consumers and charging devices. It was established that using a concentrator with optimized curvilinear blade geometry allows for the realization of the Venturi effect. This ensures local flow acceleration in the impingement zone on the blades moving in the wind direction, as well as aerodynamic shielding for the blades moving against the wind. It was found that the use of the wind flow concentrator reduces the self-starting speed threshold of the electromechanical system by 30 %, from 2.7 m/s to 1.9 m/s. Furthermore, it is shown that at a wind speed of 4.0 m/s, the output electrical power increased from 12.39 mW to 44.8 mW, representing a 3.6-fold power increase compared to the baseline configuration. The obtained results demonstrate the promising potential of utilizing this novel vertical-axis wind turbine design to expand the operational range, increase power output, and enhance the operational stability of wind turbines in low-wind areas. Keywords: wind energy, vertical-axis turbine, aerodynamic concentrator, self-starting, energy efficiency, active load.