Novel Concept for an Air-Pressure Driven Micro-Turbine for Power Generation

A novel concept for an air pressure-driven micro-turbine is proposed in this paper. Turbine and generator are embedded in one single component, thus eliminating coupling losses and misalignment issues, and improving compactness, reliability and lifetime. The machine is a single-stage axial impulse turbine with a rotor diameter of 14 mm. Electric and mechanical designs were carried out concurrently. Two prototypes of the micro-turbine were built. The first one was a not fully optimized prototype for concept proofing while the second one was designed to optimize the fluid dynamic efficiency minimizing the air consumption. In the second prototype the air flow can reach speeds up to 100000 rpm (with 2.4 bar of supply absolute pressure) and produces, when coupled to a small generator, a maximum electrical power of 13W. The maximum total efficiency is around 4% in the optimal condition while the maximum turbine efficiency is around 50%.Copyright © 2011 by ASME