The refurbished 20-year-old icing wind tunnel can create conditions of minus 20 degrees Fahrenheit, wind speeds up to 220 mph, frozen fog and a glaze of ice.
In the past, most models of what happened to water and ice on turbine blades had only been through a computer's aerodynamic projection. There wasn't any physical research to back it up.
Hu, who's been at
"We need to really know what's going on," he said. "You can use some mathematics to describe some of the theory about what it will be, but results and seeing the physics is almost impossible to see with a model based on your imagination."
The research is comprised of a
Hu's co-workers on the projects, which uses cameras and lasers, are
But winter brings its share of problems.
Ice collects on the blades and it "changes the geometry of the turbine and therefore the efficiency will drop."
The efficiency that a turbine will drop might not be too much, but one propeller with more ice than the other two can put more pressure and stress on them and the turbine itself. The results can be engine failures and shut-downs.
Ice collects in two forms: rime, which forms in cold and dry conditions and creates a layer on the blades that changes the balance but doesn't affect the aerodynamics, and glaze, which forms when it's not too cold and only a portion of a droplet turns to ice so a droplet can flow a little and creates some weird patterns.
The glaze form was something Hu was really interested in learning about.
Hu believes the research is also important because it helps us start to understand what can happen on airplanes in winter weather. The water droplets can freeze and add weight to the airplane.
Hu said in parts of
As everything melts, the ice on the propellers does come with a risk. Hu said with ice can slide off and larger pieces can be thrown more than 3,000 feet. It does pose a danger passing vehicles, but Hu only knew of one incident.
The results Hu found weren't what was expected.
"We're all pretty excited about this," he said. "We've never seen results come back from a lab and many things we've thought aren't actually happening."
Hu hopes the research will lead to more, which is certainly needed, and ideas for engineers to develop new solutions.
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