WiValdi rotor blade demonstrator - Which forces act on a rotor blade?

Rotor blade research at the Krummendeich Wind Energy Research Park

DLR's research wind farm (WiValdi) is currently under construction in Krummendeich, Northern Germany. It will have two large standard wind turbines. They are additionally equipped with innovative research sensor technologies. The sensors are placed primarily in the rotor blades.

WiValdi Rotor Blade Demonstrator

The WiValdi rotor blade demonstrator shows a 2.2m model of a rotor blade. It is similar to the rotor blades that will be used in WiValdi. A network of acceleration sensors and strain gauges is installed in the blade. The latter determine the internal stress on the material. Depending on what actions the visitor performs on the exhibit, the rotor blade deforms and the corresponding measurement data is shown on a display.

Vibration monitoring

A wind turbine vibrates due to wind gusts and turbulence excitation. Therefore the behavior of the blade is of particular interest: The exhibit shows the state of the art in the field of real-time modal analysis to estimate frequency and damping. For this purpose, vibrations and deformations are permanently recorded and evaluated autonomously using software developed at the DLR Institute of Aeroelasticity. The damping is of particular interest. It describes the period of time until the oscillation of a rotor blade stops. From this, insights can be gained into the stability behavior and service life of the wind turbine. Frequency tracking of several modes enables to determine whether ice has formed on the rotor blades - important information for shutting down turbines or defrosting the ice using a blade heater.