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Testing centre is key to study of icing in gas turbines

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.”