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Invention of the Year
  Invention of the Year
High Temperature, Flexible, Fiber Preform Seal
Glenn-developed seal is an enabling technology for high performance systems.

A patented seal developed for the National Aerospace Plane project by Dr. Bruce Steinetz, Tribology & Mechanical Components Branch, and Mr. Paul Sirocky has won NASA's 1996 Government Invention of the Year Award.

The Inventors: Paul J. Sirocky (left) and Dr. Bruce M. Steinetz
The Inventors: Paul J. Sirocky (left) and Dr. Bruce M. Steinetz

The advanced High Temperature, Flexible, Fiber Perform Seal is braided out of emerging high temperature ceramic fibers or superalloy wires into a flexible, flow-resistant seal. The device was developed to seal the flow of ultra-hot combustion gases within the National Aerospace Plane (NASP) engines to prevent the pressurized gases from leaking past the movable engine panels to rear engine cavities and causing loss of the engine or the entire aircraft. "The need to seal the hot gases and distorted sidewalls required that we develop a device having the flexibility of rubber O-rings and could operate at 2000+ deg F, a very tall order," according to Steinetz. "The high temperature fiber preform seal is one very important step in that direction."

The seal has been used for numerous NASA applications since it was patented in 1992. The patented seal technology was used by General Electric in the joint NASA/DOD/GE Integrated High Performance Turbine Engine Technology Program. The hybrid rope seal successfully sealed the perimeter of advanced nickel-aluminide turbine vane airfoils allowing the vanes to grow relative to the supporting structure, thus overcoming the thermal shock failure experienced with the conventional sealing approach. The high temperature turbine vane/seals combined with several other advanced technologies contributed to meeting the program goals of reducing specific fuel consumption by 20 percent, and increasing engine power-to-weight by 40 percent, in a successful full-scale Joint Turbine Advanced Gas Generator engine test.

The invention is being evaluated by Pratt & Whitney as a potential replacement for sealing interfaces between large nozzle turning vanes and flow-path fairing elements for the F119 engine for application in the F22 fighter, the country's next generation premier fighter. P&W will test the seal in a full scale engine in May. Williams International is evaluating the seal for an advanced turbine engine, while another engine manufacturer is considering using the seal as part of an industrial gas turbine generator for auxiliary electric power. Researchers Michael Adams and Lawrence Kren helped perform laboratory feasibility qualifying the seals for subsequent engine and industrial system tests.

NASA is developing a future replacement for the Space Shuttle and will be testing many of the technologies on an experimental vehicle, the X-33. The X-33 contractor team is exploring possible use of the NASA rope seals for sealing joints between the aerospike engine nozzles and joints between the vehicle's heat-resistant thermal tiles.

Although the seal was developed for aerospace uses, it is being evaluated for industrial applications as well. Under a reimbursable Space Act Agreement NASA Glenn is working with a major U.S. producer of industrial gases, to adapt the seal technology for use in the company's high temperature, proprietary industrial gas systems. Other potential future applications include sealing furnace doors, heat exchangers, continuous casting and glass processing equipment.

The seal is able to bend around sharp radii (about equal to the seal's diameter) conforming to and sealing complex components. In addition, the seal exhibits low leakage, retains resilience after high temperature cycling, and is capable of supporting structural loads.

Glenn has not won NASA wide competition since 1988 when Harold Sliney won the Invention of the Year Award for his high temperature solid film lubricants. Steinetz, of Westlake, joined Glenn in 1983. He earned a doctorate in mechanical and aerospace engineering from Case Western Reserve University. Bruce and his wife Caroline have 2 children and enjoy traveling and watersports. Sirocky, of Middleburg Heights, worked on many projects, including wind turbines and Space Shuttle experiments, in his 30 years at Glenn. Paul died in 1999.

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Last Updated: September 21, 2009te -->