While most planes use heat to melt ice that can form on the wing either before takeoff or during flight, the process is highly energy intensive and can impact engine efficiency. A new process from German researchers shakes the ice off instead.
Even a small amount of ice can dramatically impact the performance of an airplane wing. Because ice crystals are rough, they effectively change the shape of the wing, interrupting the smooth flow of air over its surface. This increases drag, decreases lift, and affects the plane’s longitudinal stability. So keeping wings ice-free is an important part of aviation.
Until now, the most common way to keep wings ice free is through systems that channel hot air from the engines over the wings. However, according to researchers from Germany’s Fraunhofer Institute, this uses a lot of energy and makes engines less efficient. So they decided to come up with a better way.
They developed a system that relies on tiny piezoelectric actuators embedded on the wing’s surface. These actuators vibrate when a current flows to them, and have the ability to shake off the ice that forms above them.
“The vibrations are in the range of just a few kilohertz,” said Denis Becker, a researcher at Fraunhofer. “They are invisible to the naked eye but very effective. The ice clinging to the wing breaks up and falls off.”
Fraunhofer LBF
In addition to being a greener method to keep wings ice free, the system also positions itself to work with aircraft of the future, which might not have heat-producing engines based on new propulsion technologies.
“The propulsion systems of the future will no longer produce any hot exhaust gas or waste heat, which thermomechanical deicing systems require to do their job,” says Becker. “Our method holds out the prospect of cutting energy consumption by up to 80 percent, making it an important contribution to sustainable aviation.”
Math matters
While tiny vibrating motors that shake off ice crystals might sound like an obvious way to keep airplane wings ice-free, the real breakthrough in the work came in the form of the algorithm that calculates the natural resonance frequency at which the actuators start vibrating – a frequency that can change constantly during flight.
“The determining factors include the material the wings are made from, the speed, the altitude of flight, the temperature, humidity and how thick the layer of ice is,” said Becker.
The scientists tested their algorithm-powered actuators in an icing wind tunnel, which allowed them to optimize their function and prove that they could do their job. They next plan to further dial in the actuators to get them ready for in-flight testing.
The wings were developed as part of the European Union’s Clean Aviation Project, an initiative that seeks to achieve climate-neutral aviation by 2050.
Source: Fraunhofer
