Micro-Scale Radial-Flow Compressor Impeller Made of Silicon Nitride: Manufacturing and Performance

Abstract

A micro-scale, high-speed compressor impeller (12mm diameter, 800,000 rpm) was tested for feasibility in regard to aerodynamic performance. The compressor was designed for application in a fist-sized gas-turbine-generator. To survive high stresses at such high temperatures, the rotor was manufactured as a single turbine/compressor/shaft unit in silicon nitride, by the Mold SDM process. Performance testing was conducted in a cold-flow rig at reduced speed of 420,000 rpm. Results from a CFD code compared favorably to measured data at this speed. Extrapolation from test conditions to full design speed was accomplished by application of CFD applied at both speeds.