Challenge
The kinetic energy of flow can be described as the vector sum of fluid speed and orbital speed. A favourable flow angle is necessary for the airfoil-shaped rotor blades to generate torque on the turbine's rotation axis. Tangential propulsion and suction forces are derived from uplift force. The propulsion force, as the smaller component, drives the rotor, while the suction forces cause permanent load-unload cycles that affect the load-bearing structure of the vertical-axis turbine, causing it to sway. How would a rotor blade have to be designed to generate propulsion exclusively?
Invention
The RES-Turbine's flipped-over rotor blade comprises two segments of elongated blades connected at an intermediate turning point, with the suction and drag sides of the blade flipped over. According to the invention, the orbit of a rotor blade is defined either by a constant radial distance to its axis of rotation, or by varying radial distances. The axis of rotation may be vertical or horizontal. The flipped blade has the effect of eliminating suction forces while adding propulsion forces.
Advantages
- Full compensation of suction forces within a single rotor blade
- Elimination of downwind rotor thrust
- Prevention of load change reactions
- Generation of strong and steady torque
- Generation of propulsion forces at any point in the rotor blade's orbit
Applications
- Turbines of any size, with either a horizontal or vertical axis of rotation
- Water turbines for run-of-river and tidal power stations