Sometimes a seemingly simple thing can wreak a lot of havoc. Ice is one of them. In its simplest form, when water freezes, a brittle, crystalline solid is formed. It’s slippery. It sometimes melts fast, and sometimes it doesn’t. When faced with an icy situation, few of us consider the true nature of ice, especially when we are hoping to board a plane.
On average there are more than 26,527 flights in the U.S. per day. Depending on the season and location, the only consideration ice is given by passengers is if it has melted in their drink. Depending on weather conditions, ice very well may mean flight delays, cancellations or in-flight scares. Ice forming on an aircraft is a cumulative hazard faced by the industry. It can affect the flight of a plane in many ways including increasing weight, limiting lift capabilities and impairing engine or communications functions.
Innovative solutions to limiting the effects ice has on aircraft may be just around the corner thanks to a research team at the University of Nottingham. In a press release, the team shared a new research model to help understand ice accretion—the process by which a layer of ice builds up on a solid object exposed to freezing precipitation or to supercooled fog or cloud droplets.
“Up until now, there has been a lack of work conducted on researching mixed ice,” said Zaid Ayaz Janjua, one of the paper’s author. “Our work will help inform research into thermally active nanocoatings for aircrafts to combat ice formation.”
Previous models focused on two forms of ice: glaze, smother and clear, and rime, bumpy and opaque. Rime ice forms when supercooled cloud droplets rapidly freeze, while glaze ice forms when large quantities of supercooled cloud droplets are spread out before they slowly freeze.
“You can think of rime ice as the kind of ice you could easily scrape off from the walls of your freezer, whereas glaze ice is more like ice cube ice,” Janjua said.
The Nottingham team expanded the ice accretion modeling code (ICECREMO) to include the varied spectrum between rime and glaze: mixed ice. A natural formation on inflight aircraft wings, mixed ice demonstrated very different accretion rates than the two ends of its ice spectrum. The team developed a freezing fraction to account for significant changes in ice adhesion characteristics.
“For a particular set of atmospheric conditions, you can have vastly different ice heights, which would greatly influence the amount of energy needed to remove the ice or even the tools you might select to achieve that,” Janjua said.
For airlines, the ability to understand ice adhesion and formation could enhance deicing systems, which often are costly, and eventually lead to new types of “ice-resistant” coatings. The study also could benefit other engineering applications affected by ice accretion such as communications towers, wind turbines, and electrical cables.
Interested in aircraft? Check out our visit to the Singapore Airshow 2018.