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To address this problem, aircraft are equipped with thermal systems that draw hot air from the engines and channel it across the wings. This requires a “great deal” of energy, however, according to researchers at the Fraunhofer Institute for Structural Durability and System Reliability (Fraunhofer LBF) in Darmstadt, Germany, and can affect engine efficiency. The team worked with partners to develop an alternative deicing method, announced this week (3 November).
Instead of hot air, the process uses vibrations to crack and remove ice. First, sensors detect ice formation on specific sections of the wing. The natural resonance frequency of those areas – the frequency range where the material starts to vibrate – is then determined. Piezoelectric actuators can then vibrate the spots where ice has formed.
“The vibrations are in the range of just a few kilohertz. They are invisible to the naked eye but very effective,” said Fraunhofer LBF researcher Denis Becker. “The ice clinging to the wing breaks up and falls off.”
To calculate the vibration frequency, the Fraunhofer researchers first needed to study the complex interaction of several parameters. “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. Algorithms use that information to calculate the natural resonant frequency,” Becker explained.
The project involved various steps, including tests in an ‘icing’ wind tunnel and optimisation of the piezoelectric actuators. Further wind tunnel tests are planned to get the system ready for in-flight testing, Becker added.
“The idea of using vibration to remove ice has been talked about in aviation circles for a long time now. Now, for the first time, researchers have succeeded in creating a highly dynamic and accurate system that puts this idea into real-world practice,” the announcement said.
The resonant frequencies of a wing can vary throughout a flight as conditions change, so the sensors work continuously to activate the actuators at adjusted frequencies.
The technique could be useful for aircraft using next-generation propulsion methods such as electric or hybrid power, the researchers suggested. “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. Our method holds out the prospect of cutting energy consumption by up to 80%, making it an important contribution to sustainable aviation,” Becker said.
The project is part of the European Union’s Clean Aviation research and innovation programme. Partners include aerospace firms Airbus and Parker-Meggitt.
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