Investigation on design flow of a millimeter-scale radial turbine for micro gas turbine

As compared to the conventional large scale gas turbines, the aerothermodynamics design of a micro gas turbine will be quite different not only due to the small scale effects, but also due to the constraints associated with many considerations. As a major component and main work unit of the micro gas turbine, the design flow and the design results of the micro radial turbine directly determine the physical realization of the micro gas turbine. This paper mainly presents the investigation and discussion on scaling considerations and the design flow through a micro radial turbine which with diameter of 10 mm for a 50 W-class micro gas turbine. Firstly, theoretical analysis of scaling effects, thermodynamics, fluid mechanics, turbomachinery aerothermodynamics, heat transfer and rotor dynamics are described. Secondly, four sub-modules of different design considerations are constructed and the periodical design results are presented. Finally, the design flow of millimeter-scale radial turbine is proposed. The results indicate that the distinctive design principles and design challenges are not negligible and the discussions and definitions of the design flow for the micro turbine are essential. These works not only methodize the design details, but also define the basic design flow as the reference for the new designer.