Space Shuttle Engine Technology Research Benefits American Jet Engine Manufacturer

In 1992, a series of tests were conducted to experimentally investigate the settings of the blades and vanes of the the turbine components on Pratt's high pressure fuel turbopump that goes on the Space Shuttle main engine. These tests were part of a cooperative program between NASA and P&W, one of America's premiere jet engine/rocket engine manufacturers, to analytically and experimentally study performance improvements possible by repositioning turbine vanes relative to one another.

In the test rigs there were two sets of rotating turbine blades, called rotors, and two sets of stationary vanes, called stators, which direct the flow of hot combustion gases. The 50 airfoil-shaped blades on each of the two rotors and 54 vanes on the two stators are aligned consecutively, one after the other.

The Marshall and P&W engineers studied the effects of slightly rotating the vanes on stator one relative to their downstream counterpart. The vanes were in direct alignment. Tests also studied similar rotational adjustments on the blades of rotor two relative to those on rotor one. P&W engineers were later able to apply the experimental test data obtained in the Marshall Center tests to modify turbine rotor designs in the PW- 4084 engine for the Boeing 777.

The research team learned that a significant improvement in engine efficiency could be attained through the application of this innovative alignment of turbine rotor and stator blades. By applying this concept to the new P&W engine's rotors, they were able to improve its efficiency by a full half-percent. This is a significant improvement.

A twin-engined Boeing 777 aircraft using P&W-4084 engines flying a round-trip between Los Angeles and Hong Kong, a total distance of about 12,500 miles, would save about 400 gallons of fuel. For shorter, Trans-Atlantic flights of about 6,000 miles round-trip, the savings would be about half that for Pacific operations. On an average, transoceanic airliners fly their routes three times a week. Extrapolating the fuel savings for the entire projected airline industry fleet of 92 P&W-4084 equipped Boeing 777 jets over the course of a year of operations shows an anticipated savings of more than four million gallons of fuel -- the equivalent of more than 650,000 barrels of oil.

The Pratt & Whitney engine is one of three being offered by Boeing for customers of the 777. The new Pratt & Whitney engines are projected to be installed on 40 percent of all Boeing 777s manufactured.

Some other benefits will accrue to the U.S. economy from these new engines besides greatly improved airline efficiency. US airplanes and the new fuel-efficient engines will gain an important competitive edge in the international aircraft marketplace.

As a result of the tests conducted at MSFC, the fine tuning of the airfoil blade settings also may find an application in the large electricity-generating turbines used by America's utilities. By increasing generator turbine efficiency, electric utilities could achieve significant operational cost savings. In the case of electric turbines run by fossil fuels, greater efficiency of operation means lower fuel costs and a possibly of reduced pollution.

With America's electric utilities moving rapidly toward deregulation and increased competition, this means that there will be great pressure to pass the savings on in the form of lower electric rates to the consumer.