An innovative sensor that can identify the formation of ice in real time may be a game-changer when it comes to safety and efficiency of airlines.
Two prominently different research teams—one that studies extreme liquid repellency and ice-repellent materials, and the other that designs microelectronics systems and microwave sensors—have teamed up for this latest study being performed at UBC Okanagan’s School of Engineering.
The aim of the researchers is to create a unique sensor that can detect the actual moment of the formation of ice on a surface. Microwave resonators were eventually selected by the team because of the materials’ planar profile, ease of fabrication, low power, and high sensitivity.
Assistant Professor Kevin Golovin explained that the device will make it easier to spot and control the accumulation of ice on aircraft, noting the fact that there have been several airline tragedies that were directly associated with icy airplane wings.
The ice detection systems used today are quite rudimentary. For example, pilots visually detect ice on aircraft wings before de-icing in flight. And on the tarmac, certifying that the aircraft is free of ice after de-icing is also done by visual inspection, which is susceptible to human error and environmental changes.
Kevin Golovin, Assistant Professor, The University of British Columbia
The Okanagan Polymer Engineering Research and Applications Lab is run by Golovin.
Although planar microwave resonator sensors enable simple traces of metal deposited onto a plastic, they are sensitive, mechanically strong, and can be fabricated easily, explained Mohammad Zarifi, Assistant Professor and head of UBCO’s Microelectronics and Advanced Sensors Laboratory.
“The sensors give a complete picture of the icing conditions on any surface, like an airplane wing. They can detect when water hits the wing, track the phase transition from water to ice, and then measure the thickness of the ice as it grows, all without altering the aerodynamic profile of the wing,” stated Zarifi.
The duo, together with graduate students Kiana Mirshahidi and Benjamin Wiltshire, has recently reported the study results in Sensors and Actuators B: Chemical. This is the first-ever report that shows how microwave resonators can be used for detecting the buildup of ice or frost, stated Zarifi. The reverse is also feasible—that is, the sensors can detect when the ice begins to melt away during de-icing, he added.
The sensors’ accuracy and sensitivity means the detection happens in real time. That could make both in-flight and ground de-icing cheaper, faster¸ and relatively more efficient.
The resonator detected frost formation within seconds after the sensor was cooled below freezing. It took about two minutes at -10 C for the frost to become visible on the resonator with the naked eye—and that’s in one small area in ideal lab conditions. Imagine trying to detect ice over an entire wingspan during a blizzard.
Ben Wiltshire, Study First Author, The University of British Columbia
Recently, planar microwave resonator devices have shown considerable performance in characterizing, monitoring, and sensing liquid, solid, and gaseous materials. Yet, studies on ice and frost detection have not been performed until now, added Zarifi, in spite of the evident advantages of robust, sensitive, and real-time detection for safety and transportation applications.
“This is a brand-new method for detecting ice formation quickly and accurately,” stated Zarifi. “The radiofrequency and microwave technology can even be made wireless and contactless. I wouldn’t be surprised if airlines start adopting the technology even for this upcoming winter.”