DTU Wind Energy tests sections of a blade in the Poul la Cour Tunnel at DTU Risø Campus.
For wind turbines, it is important to quantify the aerodynamic performance of their rotors with their blades. To quantify this in controlled conditions, wind tunnels are very efficient.
However, modern wind turbine blades are longer than 50 meters. It is thus not possible to test the blades in full length in wind tunnels.
Therefore, DTU Wind Energy tests sections of a blade in the Poul la Cour Tunnel at DTU Risø Campus.
In the wind tunnel, a setup for such tests have been designed to carry out tests of blade sections in a smooth and efficient manner. A blade section can be installed between the two turntables in the floor and in the ceiling. With pressure tubes, the lift of the blade section can be measured. Furthermore, the deficit of the flow created at the lee side of the blade section can be measured by numerous pressure tubes mounted in a so-called wake rake and in this way, the drag of the blade section can be determined.
“We have now carried out numerous tests on blade sections up to 105m/s. In comparisons to other high quality wind tunnels we can see very good agreement and we look very much forward to testing many more models”, says Christian Bak, head of the Poul la Cour Tunnel.
In the photo above, a blade section is seen vertically between the two turntables in the test section in the Poul la Cour Tunnel. Also, the wake rake is seen in the foreground with its pressure tubes that can move to the sides and up and down. Through the windows in the test section, wedges for absorption of noise can be spotted.