APP82: Feasibility Study of a MEMS Viscous Rotary Engine Power System (VREPS)


In this project an analytic, theoretical and numerical study of the Viscous Rotary Engine Power System (VREPS) is completed. In addition, a proposed process flow for the fabrication of the VRESP using DRIE of silicon is developed. The design premise of the VREPS is to derive mechanical power from the surface viscous shearing forces developed by a pressure driven flow present between a rotating disk or annulus and a stationary housing. The resulting motion of the rotating disk or annulus is converted into electrical power by using an external permanent magnet, embedded nickel-iron magnetic circuits, and an external switched magnetic pole electric generator similar to the design proposed by M. Senesky for the UC Berkeley micro-Wankel Engine [1]. This project will examine the power output, isentropic efficiency, dynamic stability, and operating characteristics of the disk and annular viscous turbines. The viscous turbine is optimized for maximum isentropic efficiency using MATLAB numerical optimization routines. A unique triple-wafer micro-fabrication process for VREPS is also developed. The proposed design consists of a 250 ƒÝm thick, 3.4 mm OD / 2.4 mm ID annular rotor with embedded magnetic poles and four 10 ƒÝm driving channels on each side of the rotor. Electrical power is generated with a switched magnetic pole generator, external permanent magnet, and integrated magnetic circuits. Calculations with water predict an output power of 825 mW at an isentropic efficiency of 25% using a pressure drop of 5 MPa.

Project end date: 01/20/05

Thomas H. Cauley III
Publication date: 
September 10, 2004
Publication type: 
BSAC Project Materials (Final/Archive)
PREPUBLICATION DATA - ©University of California 2004

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