Featured Research

from universities, journals, and other organizations

Icing wind tunnel blows cold and hard to study ice on wings, turbine blades

Date:
February 12, 2014
Source:
Iowa State University
Summary:
Engineers have refurbished an icing wind tunnel and are using it to study ice buildup on aircraft wings and wind turbine blades. A better understanding of the icing problems could lead to better solutions.

Iowa State's Hui Hu examines ice on a test model taken from the university's Icing Research Tunnel. The refurbished tunnel, which has been fully functional for a few weeks, is in the background.
Credit: Photo by Bob Elbert/Iowa State University

From somewhere back behind the Iowa State University Icing Research Tunnel, Rye Waldman called out to see if Hui Hu was ready for a spray of cold water.

The wind tunnel was down to 10 degrees Fahrenheit. A cylindrical model was in place inside the 10-inch-by-10-inch test section. The wind was blowing through the machine at 60 mph. So yes, said Hu, an Iowa State professor of aerospace engineering, turn on the water.

Waldman, a post-doctoral research associate, hit the controls and three spray nozzles threw a fine mist up into the wind. The tiny water droplets circulated through the tunnel, hit the model and started freezing. Within minutes, the frozen droplets distorted the model's smooth and regular shape.

That ice is the result of a three-year project to fully refurbish a 20-year-old icing wind tunnel donated to Iowa State by the Goodrich Corp. (now UTC Aerospace Systems). The wind tunnel can operate at minus 20 degrees Fahrenheit with wind speeds as high as 220 mph. It can create everything from frozen fog to wet glaze ice. It has been fully functional for a few weeks.

"We're trying to understand how the ice builds up on aircraft wings and wind turbine blades," Hu said. "We want to understand the underlying physics. And when we understand the physics, we can develop better models to simulate and predict when and how ice will build up on cold days."

Ice can build up "to quite ugly things" that are dangerous and costly, Hu said.

Ice changes the geometry and balance of wings and blades. That can rob aircraft wings of lift and cause crashes. It can reduce the efficiency of wind turbine blades tremendously, cutting the power harvest from winter's strong winds. It can also throw off the balance of a wind turbine's spinning blades, putting tremendous forces on shafts and machinery, leading to failures or shut-downs. Thawing ice on turbine blades can also be thrown hundreds of yards, potentially hitting people, buildings or vehicles.

With a better understanding of the icing problems, Hu said engineers could develop better solutions.

Hu said there are only a few icing wind tunnels in the country, and the ISU Icing Research Tunnel is the only one on a university campus.

Hu will use the tunnel as part of a $663,000 grant from NASA to study icing of aircraft wings, part of a $360,000 grant from the National Science Foundation to study icing of wind turbine blades and part of a $20,000 seed grant from Iowa State's Institute for Physical Research and Technology to develop new technology to study aircraft icing. He's working on the projects with Alric Rothmayer, an Iowa State professor of aerospace engineering; Kai Zhang, a doctoral student; and Waldman.

They're using cameras and lasers to take advanced flow measurements, including particle image velocimetry, molecular tagging thermometry and digital image projection.

"In the past, there haven't been many quantitative experiments to let people see the underlying physics of wing and turbine blade icing," Hu said. "This is what's really needed."

Hu's experiments, for example, show everything from the thickness of ice as it flows over a wing, the heat transfer of individual water droplets as they freeze, the irregular speed of freezing droplets on a wing or blade and the finger-like patterns of ice formation.

Though they share similar airfoil shapes, Hu said icing on aircraft wings and wind turbine blades can be quite different.

That's because wings are typically made of metal, have very smooth surfaces and are good heat conductors. Turbine blades are typically a composite such as fiberglass, have rougher surfaces and don't conduct heat very well. Wings also operate under drier conditions when they're at altitude; turbine blades near the surface are in the middle of winter sleet and snow.

"All of that makes a huge difference," Hu said.

So far, most of the data about airfoil icing is related to aircraft.

"But the anti-icing strategies that work for aircraft might not be best for a wind turbine," he said.

Now that Iowa State's icing wind tunnel is up and running and looking brand new, Hu said Iowa State engineers will be gathering more and more data about all kinds of icing issues.


Story Source:

The above story is based on materials provided by Iowa State University. Note: Materials may be edited for content and length.


Cite This Page:

Iowa State University. "Icing wind tunnel blows cold and hard to study ice on wings, turbine blades." ScienceDaily. ScienceDaily, 12 February 2014. <www.sciencedaily.com/releases/2014/02/140212093144.htm>.
Iowa State University. (2014, February 12). Icing wind tunnel blows cold and hard to study ice on wings, turbine blades. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2014/02/140212093144.htm
Iowa State University. "Icing wind tunnel blows cold and hard to study ice on wings, turbine blades." ScienceDaily. www.sciencedaily.com/releases/2014/02/140212093144.htm (accessed October 20, 2014).

Share This



More Matter & Energy News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Gulfstream G500, G600 Unveiling

Gulfstream G500, G600 Unveiling

Flying (Oct. 20, 2014) Watch Gulfstream's public launch of the G500 and G600 at their headquarters in Savannah, Ga., along with a surprise unveiling of the G500, which taxied up under its own power. Video provided by Flying
Powered by NewsLook.com
Japanese Scientists Unveil Floating 3D Projection

Japanese Scientists Unveil Floating 3D Projection

Reuters - Innovations Video Online (Oct. 20, 2014) Scientists in Tokyo have demonstrated what they say is the world's first 3D projection that floats in mid air. A laser that fires a pulse up to a thousand times a second superheats molecules in the air, creating a spark which can be guided to certain points in the air to shape what the human eye perceives as an image. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-Fuel Impala

3BL Media (Oct. 20, 2014) Hey, Doc! Sewage, Beer and Food Scraps Can Power Chevrolet’s Bi-fuel Impala Video provided by 3BL
Powered by NewsLook.com
What We Know About Microsoft's Rumored Smartwatch

What We Know About Microsoft's Rumored Smartwatch

Newsy (Oct. 20, 2014) Microsoft will reportedly release a smartwatch that works across different mobile platforms, has a two-day battery life and tracks heart rate. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins