Usually they try to increase the efficiency of wind turbines by improving the air flow around the blades, finding the most profitable modes of operation of the wind turbine, finding the best blade profiles, etc. In the proposed project, we are following an unusual path. Based on our understanding of the nature of the pulling aerodynamic forces when flowing around symmetrical airfoils at low angles of attack (less than 10 degrees), we propose to roll the blades of the vertical-axis Darrieus rotor into rings (Figure 1).

In this case, the swept area of the wind turbine is reduced, and the rings turn into something like a ramjet engine. The longitudinal section of the ring represents a Laval nozzle in its pure form, while a pseudo nozzle appears outside, formed by the outer profile of the ring and the flowing air. (Figure 3) These forces constitute the main pulling forces of the wind turbine. Small pulling forces also arise on the wings (wings), which also have a symmetrical profile (Figure 2).

Like all rotors of this type, the proposed rotor must be pre-spinned and, when the linear speed of the rings reaches approximately 100 km/h, the motor turns into a generator and supplies energy to the network. The concentration of pulling forces in the ring will significantly increase the efficiency of the rotor. The design will be simplified and the stability of the wind turbine will increase.