- We will look at how ice affects the loads on the wings, for it is quite a lot of weight coming on the wings and our piece is above all to be able to measure the ice, says Johan Casselgren, researcher in the Department of Fluid and Experimental Mechanics at Luleå University of Technology.
More and more small and large wind farms are being built in the northern districts where it during parts of the year is a cold climate with icing which means limiting energy production. There are already techniques for using cameras to assess ice in large surfaces, but it is slow and only works on clear ice. The research led by Johan Casselgren is all about how to develop a technique that is fast, robust and reliable. It occurs by illuminating the wings with three wavelengths of near infrared and shoot it with a camera that is sensitive to near infrared light (NIR).
- The idea is that we should use such a camera that can capture an entire blade so that we can see how the ice begins to form on the blade. It allows us to couple such data with how the wings are affected in terms of how they are bent and twisted. What we will also work with is to develop a technique for measuring grain size of the snow and the density of the ice has, he says.
The research is part of a larger project called "Vibrations and loads of wind turbines at ice load" with Swedish Energy Agency as the main financier. Whitin the project is also some international cooperation with Gyeongsang National University in South Korea who donated a mini wind power mill to the research project.
- It is difficult to do testing on a giant wind turbine but now we have fortunately a little one that we can start on, which is horizontally and a little easier. Instead of testing on a wing which is 120 meters long, so we can test this technology on a small scale in order to later make bigger tests, says Johan Casselgren.
The project includes, besides Johan Casselgren, also PhD Lavan Eppanapelli, Benjamin Friberg and a number of students taking the project C course with a focus on energy.