Demonstration of a Microfabricated High-Speed Turbine Supported on Gas Bearings

A single-crystal silicon air turbine supported on gas lubricated bearings has been operated in a controlled and sustained manner at rotational speeds greater then I nullion rpm and power levels approaching 5 W. The device is a second-generation version of the microbearing rig first reported by Lin et al. [I], and is the first raicromachine to operate at circumferential tip speeds of hundreds of meters per second, comparable to conventional scale turbomachinery. To achieve this level of peripheral speed, microfabricated rotors must withstand large induced stresses, need a sufficient power source to drive them, and require stable, low friction bearings for support. This paper focuses on process improvements in the niicrobearing device fabrication and on the advances in operating micro-gas bearings and micro- turbomachinery. The successful operation of this device motivates the use of this technology for high-power density MEMS. Presented at the Solid-State Sensor and Actuator Workshop held in Hilton Head Island, SC on 4-6 Jun 2000. Sponsored in part by Defense Advanced Research Projects Agency contract DABT63-98-C-0004.