Following several months refurbishing a special NASA test rig, GE Aviation and NASA this summer will begin a wind-tunnel test program to evaluate counterrotating fan-blade systems for "open rotor" jet engine designs.
The testing will be conducted throughout 2009 and early 2010 at wind tunnel facilities at NASA's Glenn Research Center in Cleveland, Ohio. This is not a full engine test, but a component rig test to evaluate subscale fan systems using GE's and NASA's advanced computational tools and data acquisition systems.
In the 1980s, GE successfully ground-tested and flew an open-rotor jet engine that demonstrated fuel savings of more than 30 percent compared with similar-sized, jet engines with conventional, ducted front fan systems. Since then, GE has dramatically advanced its computational aero-acoustic analysis tools to better understand and improve open-rotor systems.
"The tests mark a new journey for GE and NASA in the world of open rotor technology," said David Joyce, president of GE Aviation. "These tests will help to tell us how confident we are in meeting the
technical challenges of an open-rotor architecture. It's a journey driven by a need to sharply reduce fuel consumption in future aircraft."
GE and the Fundamental Aeronautics Program of NASA's Aeronautics Research Mission Directorate in Washington are jointly funding the program. Snecma (Safran Group) of France, GE's longtime 50/50 partner in CFM International, a highly successful joint company, will
participate with fan blade designs.
For the NASA tests, GE will run two rows of counterrotating fan blades, with 12 blades in the front row and 10 blades in the back row. The composite fan blades are 1/5 subscale in size. They will be
tested in simulated flight conditions in Glenn's low-speed wind tunnel to simulate low-altitude aircraft speeds for acoustic evaluation, and also in Glenn's high-speed wind tunnel to simulate high-altitude cruise conditions in order to evaluate blade efficiency and performance.
Engine noise is a prime challenge in operating open-rotor engines in a commercial aviation environment.
NASA's test rig, now refurbished and modernized, was actually used in the 1980s when NASA and GE first tested scale-model, counterrotating fan systems that led to the development of the open rotor GE36 engine.
The first wind-tunnel tests this summer will essentially reenact those 1980s tests. GE and NASA will first run blades of the same design that led to the original GE36 jet engine. This will establish critically important baseline data for GE for flight test correlation because the GE36 in the 1980s flew on Boeing 727 and MD-80 aircraft.
As new and more exotic fan blade designs are run in the wind tunnel, GE and NASA will be able to assess comprehensive aero and acoustic design space in order to better understand how these designs will perform in an actual operating environment.
In total, GE and NASA will run six different sets of blades in the NASA wind tunnels, including five sets of modern blade designs. GE designed and fabricated the scale-model blades at its Cincinnati facility using technical input provided by the GE Corporate Research Center in New York.
Open-rotor jet engine designs are among the longer-term technologies being evaluated for LEAP-X, CFM International's (GE/Snecma) technology program focusing on future advances for next-generation CFM56 engines.
NASA's Aeronautics Research Mission Directorate, in partnership with U.S. industry, universities, and other government institutions, develops critical systems technologies and capabilities that address national priorities.
GE Aviation, an operating unit of General Electric Company (NYSE: GE), is a world-leading provider of commercial and military jet engines and components as well as integrated digital, electric power, and mechanical systems for aircraft. GE Aviation also has a global service network to support these offerings. For more information, visit us at www.ge.com/aviation.
The enormous efficiency from bypass air created by this fan system drove the GE36's dramatic fuel savings. As fuel prices fell sharply in the late 1980s and early 1990s, the GE36 was never launched commercially, though it was recognized worldwide as a technology breakthrough.