Hybrid Foil/Magnetic Bearing

Mohawk Innovative Technology, Inc. (MiTi) has conceived a unique hybrid foil/magnetic bearing design that is compact, light weight and uses a control strategy that optimizes the total bearing system performance. The hybrid bearing being proposed for this effort builds upon the air Force IHPTET and Navy investment in foil and integrated rotordynamic-magnetic bearing design analyses that resulted in the development and demonstration of a 97 psi load capacity foil bearing with enhanced damping capability and magnetic bearings in a large turbine generator. With the maximum foil bearing load capacity and temperature capability (1300 F) exceeding that of magnetic bearings, there exists significant potential to develop a hybrid bearing system with capabilities well in excess of either bearing alone in the same or smaller configuration than presently possible.d In addition, the increased load capacity of this hybrid bearing concept provides needed capability in sustaining transient shock events without the life limiting intermittent rubs that occur in conventional magnetic and backup bearing combinations. A four-task six-month effort is proposed that will: (1) add foil bearing analysis into the already integrated rotordymanic-magnetic bearing analysis; (2) conduct design tradeoff studies with the new integrated design analysis to assess the benefits of the hybrid foil magnetic bearing in an Army gas turbine engine, using General electric provided engine data; (3) demonstrate the key control strategy needed to integrate these two bearing technologies in a single bearing tester provided at no cost to the program and in the process verify the integrated design analysis; (4) prepare a final report and Phase II proposal for fabrication and test of a hybrid bearing in a rotor simulator representative of an Army engine in collaboration with GEAE.