This Small Business Innovation Research phase I project will develop a new type of `hybrid foil/magnetic bearing` with associated control systems. The concept is based on the combination of the technology of the magnetic bearing with that of the foil bearing, the latter acting in an auxiliary or enhancement role. Actuators incorporated in the foil bearing will allow active control of the foil to: (a) retract during normal magnetic bearing operation, (b) increase the load capacity of the entire support system during operational transients or peak load situations, (c) assist the magnetic bearing in passing through rotor critical speeds during start-up and coast-down while still maintaining small clearances, (d) act as a stand alone during magnetic bearing failure , and (e) lock-up the shaft to avoid damage to the magnetic bearing when the system is not powered. Other innovative features of this research are: the use of either gas (e.g. air) or liquid fuel as a bearing lubricant, (b) the use of similar control action in both the magnetic and foil bearings, (c) the use of piezoelectric actuators for high bandwidth control of the motion of the foil. Phase I of the research will be a feasibility study using both numerical simulation and experimental testing on the existing components. A test rig will be constructed and run for testing and verification of the concept. The results from this phase will be a) a reliable simulation and design algorithm, b) experimental knowledge base regarding the operation of the foil and magnetic bearings in tandem, as well as individually, c) the design of a preprototype, for experimentation in Phase-II, and d) the initiation of strategic alliances with industrial partners. If successful, the hybrid bearings should find wide market applications in jet engines, compressors, turbopumps, and other rotating machinery. In addition to its capability of reducing power loss and wear, the hybrid bearing also has excellent potential for supporting systems that experience repeated extreme transient loadings.
