Geared turbofan is green leader, says MTU
German-based engine manufacturer MTU Aero Engines is here at the Paris Air Show (Hall 2 Stand AB 151) exhibiting a cutaway mockup of a geared turbofan. This is the basic concept for its Claire (clean air engine) technology program, whose aim is to cut carbon dioxide (CO2) emissions by 30 percent by 2035. It is making its first step under the umbrella of the European Commission’s Clean Sky joint technology initiative.
MTU research engineers are optimizing an existing geared turbofan, focusing on the high-pressure (HP) compressor and the high-speed low-pressure (LP) turbine. They hope to reduce the turbine’s length and weight, while improving efficiency via a new concept for the first stage of the LP turbine. The target in fuel burn reduction is 15 percent for this first step.
The company is investing some ?20 million ($27 million), an amount the European Union is matching thanks to the private-public Clean Sky partnership.
In addition, industry partners such as Avio and Volvo Aero are bringing almost ?30 million ($40 million) to the project. The demonstrator is scheduled to make its first run in 2012.
For its second step, MTU plans to combine a two-stage counter-rotating fan with the geared concept, targeting a fuel burn reduction of 20 percent by 2025. The company claims to have tested a counter-rotating fan in the 1980s.
The third step is adding a recuperator. MTU has, for years, been keen on implementing heat exchangers. Under the “intercooled recuperative aeroengine” concept, exhaust nozzle heat is used to increase the temperature of the air entering the combustor. In addition, the air is cooled between the LP compressor and the HP compressor. It hope that with the additional efficiency, fuel burn will be reduced by 30 percent over current engines by 2035.
According to MTU, all key components for the Claire program are available and successfully tested. They meet the company’s expectations in terms of energy efficiency and cost-effectiveness.
MTU also is a partner in Pratt & Whitney’s new PW1000G program, the geared turbofan selected for the Mitsubishi Regional Jet and the Bombardier C Series. In addition to the PW1000G, the company’s major development partnership programs include the PW810 for the Cessna Citation Columbus (now on hold) and the General Electric GE38 for the Sikorsky CH-53K heavy-lift transport helicopter. Also, late last year, MTU took 6.6 percent of General Electric’s GEnx program, the engine that is to power the Boeing 787 and the 747-8. It will be responsible for the turbine’s center frame. The company estimates that the risk-and-revenue-sharing deal could be worth more than ?11 billion ($14.8 billion) over the life of the program.
On the Maintenance Front
In maintenance news, in April, MTU Maintenance Hannover celebrated working on the 5,000th engine to enter its shop. It was a CFM56-7 off the wing of a Boeing 737-800 from TUIfly airline’s fleet. The facility’s new test cell can accommodate powerplants of up to 150,000 pounds of thrust.
In maintenance technology, MTU claims to have a unique patch repair technique for blisk blades, approved since early last year. Technicians use laser powder cladding, where a high-energy laser beam welds a powdery filler material onto a component. The added layers are typically 0.2 to 0.5 millimeter thick. The laser powder cladding technique is said to cause minimal heating and distortion of the workpiece.
For 2008, MTU reported a 6-percent increase in revenues, to ?2.7 billion ($3.6 billion), and achieved profits of close to ?180 million ($243 million). The company spent ?101 million ($136 million) on research and development and employs about 7,500 people in total.
In other company news, last month MTU inaugurated its Polish subsidiary near Rzeszów Airport. It has invested ?50 million ($67 million) in MTU Aero Engines Polska, which occupies a site of almost 200,000 sq ft.
The complex has two wings: one housing the development and administration offices, the other accommodating the machine pool for production and repair. The company undertake the development and manufacture of stator vanes and rotor blades for LP turbines, the assembly of LP turbines and parts repair.
Also last month, MTU sold its U.S. manufacturing facility to EDAC Technologies for an undisclosed sum. The move is part of a shift in the group’s production capacity which will see less highly engineered components produced in the new Polish facility. Under EDAC, the Newington, Connecticut factory will continue to make rotating components such as disks, rings and shafts.