Vibration technology can prevent aircraft wings from freezing and replace energy-intensive methods

In the Clean Aviation project, Fraunhofer researchers worked with partners to develop a system that removes ice by vibrating the freezing point on aircraft wings. This significantly reduces the amount of energy required for deicing compared to traditional methods. This technology is also suitable for future low-emission promotions.

When ice forms on the wings of an aircraft, it is dangerous to the entire aircraft. Ice can reduce lift, increase drag, and impair the mobility of control surfaces such as elevators, ailerons, and rudders. In the worst case scenario, the plane could stall in mid-air and crash.

This problem can occur at any time of the year, especially when the plane passes through clouds or a layer of cold, moist air after takeoff or during approach. To address this issue, aircraft are equipped with thermal systems that draw hot air from the engine and direct it across the surface of the wing. However, this process requires a large amount of energy and also affects engine efficiency.

Fraunhofer Institute for Structural Durability and System Reliability LBF is currently working with partners to develop energy-saving de-icing methods. The basic idea is that by vibrating the icy parts of an aircraft wing, the ice will crack and flake off.

First, sensors detect icing on specific parts of the wing. The natural resonant frequency, i.e. the frequency range at which the material begins to vibrate, is then determined, followed by actuation of the piezoelectric actuator. The actuator triggers low-frequency material vibrations that target 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 they are very effective. They cause the ice on the wings to break up and flake off,” explains Fraunhofer LBF researcher Dennis Becker.

Wing resonant frequency

To calculate the vibrational frequency, Fraunhofer researchers first had to study the highly complex interaction of the various factors that cause the natural resonant frequency when ice forms.

“Determining factors include wing material, speed, flight altitude, temperature, humidity, and ice layer thickness. The algorithm uses that information to calculate the natural resonant frequency,” Becker explains.

During flight, external conditions constantly change, so the resonant frequency also changes. Thickening or melting of the ice film is also a factor. The sensor therefore continuously supplies new measurement information, allowing the electronics to operate the actuator at a regulated frequency at any time.

For this research project, Fraunhofer experts underwent various steps, including installing the wing in an icing wind tunnel and optimizing the way the piezoelectric actuators operate.

The idea of ​​using vibration to remove ice has long been discussed in aviation circles. Now, for the first time, researchers have succeeded in creating a highly dynamic and accurate system that puts this idea into practice in the real world.

“Experiments in the icing wind tunnel have shown that electromechanical de-icing works. As a next step, we will conduct further tests in the wind tunnel to prepare the system for in-flight testing,” says Becker.

Future low-emission aircraft powertrains

Fraunhofer LBF experts carried out this research project as part of the European Union’s Clean Aviation Research and Innovation Program. Partners include aircraft manufacturer Airbus and aerospace company Parker Meggitt.

The aviation sector has recently faced major challenges. Energy consumption and carbon emissions will need to decrease dramatically in the coming years. Across the industry, manufacturers are working to develop more environmentally friendly powertrains, including electric and hybrid drives.

“However, future propulsion systems will no longer produce the hot exhaust gases and waste heat that thermomechanical design systems require to do their job. Our method has the prospect of reducing energy consumption by up to 80%, making it an important contribution to sustainable aviation,” Becker explains.