Tests of two major new high-pressure (HP) components, an advanced compressor and turbine, have begun as part of CFM International's Tech56 programme - a three-year effort to develop technology for CFM56 upgrades as well as a potential new generation of engines.
The tests, involving a six-stage HP compressor and a reduced shock HP turbine, follow the successful completion of full-scale blade-out rig tests on a 152cm (60in)-diameter, wide-chord, swept-blade design.
CFMI, which tested the new blade configuration at Villaroche, France and Peebles, Ohio, says the tests revealed more than 2% higher flow at speed compared to the CFM56-7, which has the first wide-chord blade design in use on a CFM56 variant. "In the same size fan, the swept blade could provide 5% to 6% more thrust and as much as a 1% fuel burn improvement compared to the current CFM56-7 wide-chord fan," says CFMI.
A new series of tests are planned using a 172cm-diameter hollow swept fan for potential application on Airbus aircraft. "Studies on the potential application of this technology will continue over the next 18 to 24 months," says CFMI, which is to conduct performance, crosswind and ingestion tests on the larger fan in an exact repeat of its earlier tests on the Boeing 737-sized blade set.
The blade-out tests, meanwhile, caused "only limited damage to the surrounding blades and no material loss other than the released blade. All parts were contained," says CFMI.
Tests of the new compressor, which is designed to achieve a higher pressure ratio with three fewer stages than the current design, will run for about 100h, over the next six weeks and will validate the performance, operability and aeromechanical characteristics of the new design.
The HP turbine tests, which will evaluate the effect of the new design on reducing downstream turbine shock strength and the interaction between high- and low-pressure turbine stages, will run for 75h over about four weeks.
Source: Flight International
