Cold weather testing centre is key to study of icing in gas turbines

NRC, Rolls Royce, and PWC collaborate on high-thrust turbofan research .

June 2011 — The National Research Council of Canada (NRC) is engaged in a $42 million joint venture with Rolls-Royce Canada Limited and Pratt & Whitney Canada (PWC) to advance research on internal icing in gas turbine engines.

The Global Aerospace Centre for Icing and Environmental Research (GLACIER) facility is a specialized 9-metre-diameter wind tunnel that sprays super-cooled water mist into the world’s smallest and largest aircraft turbines. Located in Thompson, Manitoba, the facility recreates operating conditions that can cause unusual internal icing, allowing engineers and researchers to monitor them. The facility is now fully operational, and operating near capacity.

NRC has generated data for icing certification specifications for nearly 5 decades at its existing gas turbine lab in Ottawa. This lab can test smaller engines found on light corporate jets. In contrast, GLACIER’s test bed can handle engines five or six times more powerful – capable of generating up to 150,000 pounds of thrust. By comparison, the largest turbine now built has around 120,000 pounds of thrust, so the facility can handle future increases in engine size.

Pratt & Whitney and Rolls-Royce are the principal owners of the state-of-the art facility, while NRC and other research bodies are contributing their areas of expertise. Recognizing NRC’s global reputation in gas turbine engine research, Rolls-Royce and Pratt & Whitney approached the agency to develop, maintain and update this new facility over its life. In exchange for helping its partners test and certify engine designs, NRC gains access to the facility for research, development and training related to improving gas turbines and aircraft-icing sensors.

“GLACIER is a highly advanced centre for ice testing; the findings of this research is critical to the aerospace industry to ensure engine dependability and quality,” says Walter Di Bartolomeo, chairman of the board of GLACIER. “The centre will also be a global leader in cold weather research which will deliver important benefits to the aviation industry, worldwide.”

Rolls-Royce plans to use the facility for certification program of its new Trent XWB engine, developed to power the Airbus A350 aircraft family. Pratt & Whitney will test the new Geared Turbofan-PurePower engine, earmarked for first application on Bombardier Aerospace’s new C-Series airliner. The facility will also be used for a variety of performance, endurance and specialty testing in on a year-round basis outside icing season.

Gas turbine icing can reduce power and, in extreme cases, flame out or damage engines. It can also choke multiple sensors, misleading the on-board computers that now routinely manage airliner flight control systems, en route.

The causes of ice-build-up are yet to be fully understood in certain design, speed and atmospheric conditions, but research suggests a complex causal brew. The internal design of turbojets affects icing, yet identical engines seated on different aircraft types accumulate ice differently. This problem occurs at altitudes near 40,000 feet, where atmospheric moisture is unexpected. Small-scale tests conducted by NRC have shown that at temperatures well above freezing, internal engine surfaces can collect ice surprisingly rapidly under special conditions.

Regulators in North America and Europe will start certifying commercial turbojet engines against this type of ice build-up beginning in 2012. Current research data from NRC and its collaborators will inform the regulatory bodies. “Every new engine design will be required to survive internal icing,” says Dr. Ibrahim Yimer, Director of the Gas Turbine Laboratory of NRC Aerospace.

Research at the GLACIER facility will help scientists improve sensors, replicate icing conditions at sea level, and discover exactly what happens when aero turbines ingest ice crystals.

The funding of $42 million for this facility includes a Government of Canada investment of $13.4 million, and a $9 million secured, repayable loan from the Province of Manitoba; with the balance coming from the aerospace industry.

“The GLACIER facility is made to handle the future,” says Dr. Yimer. “Its main goal is to make flight safer. Our role here is to help regulatory agencies and engine manufacturers make sure aircraft engines are safe for flight, not just in Canada but in the U.S., Europe, and across the world.”

About the National Research Council Canada

Recognized globally for research and innovation, the National Research Council Canada is a leader in the development of an innovative, knowledge-based economy for Canada through science and technology. Its Institute for Aerospace Research is Canada's national aerospace laboratory, undertaking and promoting research and development in support of the Canadian aerospace community in matters affecting the design, manufacture, performance, use and safety of aerospace vehicles.

For more information, visit the NRC’s website