Efficient micro turbines are expected to play a major role in power generation in the coming years. One of the biggest challenges in significantly increasing the system efficiency from the currently achievable values is the availability of high temperature materials that can be micro-fabricated with a low value of relative tolerance. This paper suggests a possible solution for both the material and the fabrication technique by which this goal can be achieved. Thermodynamic analysis shows that high turbine inlet temperatures, high isentropic efficiencies, and a recuperator with high effectiveness and low pressure losses are imperative to improve system efficiency, particularly in a micro turbine. An excellent relative tolerance with a high temperature ceramics is one way to achieve these improvements. The paper introduces new polymer-derived-ceramics (PDC), which could be used in turbine and recuperator designs. These materials can be used in micro-fabrication techniques to produce absolute tolerances of a few microns, and some of them are thermally stable up to 1800°C in air. The paper presents an enhancement to the typical micro-stereolithography technique, by which PDC can be micro-fabricated to form parts up to a few centimeters in overall linear dimensions and yet to have a relative tolerance that is comparable to or better than that in large-sized conventional parts. It is projected that for a turbine with 10 cm rotor outside diameter and 5 mm blade height, a tip-gap-to-blade-height ratio of better than 0.28% can be achieved by this proposed enhancement. This technique appears to be quite promising for next generation micro turbines, and hence requires further investigation and development.

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