Resistance rotor (turbine)
A drag rotor is a type of impeller of a turbine . It is used in particular in wind and water turbines , the mode of operation of which is based primarily on the use of flow resistance.
effect
Depending on the aerodynamic principle used to generate torque , propellers and turbines are divided into drag and lift rotors. While the speed of buoyancy surfaces is significantly greater than that of the inflowing medium , a drag surface can only be moved at maximum with the flow speed of the medium; this means lower performance for the same area or size . The advantages of resistance rotors are a relatively large starting torque and a low structural load.
Examples
In wind energy, the design of the resistance rotor has not prevailed, even though what is probably the oldest wind turbine in the world, the Persian windmill , was a vertical-axis resistance rotor.
Further examples of resistance rotors can be found in the drives of paddle steamers . Even spinnakers , which are set at right angles to the apparent wind, only use the resistance principle.