Optimization of 200 to 3000 W Gas Turbine MEMS Arrangement

The persistent increase in demand for compact efficient power generation plants for the decentralized power supply systems applications, pipelines, micro air vehicles, electronics, etc stipulates developments of independent micro sources. Application of the micro gas turbine engine (μGTE) as an electric generator drive allows a sharp increase in the specific energy and operation independence, elimination of ambient temperature effects on the specific power, environmental friendliness improvement. However, GTE miniaturization causes its efficiency decreasing. Hence, there is a need in improvement of the micro engine of 200–3,000W power efficiency. The approach proposed is the ceramic tunnel turbomachine concept for the regenerative μGTE (MEMS-based) application [1, 2, 3] with conventional annular systems of vanes replaced with three-dimensional conic channels. The μGTE turbocompressor unit design is dependent on the conceptual arrangement approach i.e. a manner the gas turbine engine micro turbocompressor (μTC) is joined with the driven micro electric generator (μEG) assumes a great importance. Two conceptually opposite μTC concepts over the turbocompressor unit are considered: - the μTC rotor connected with the μEG rotor by an electromagnet coupling; - appropriate elements of μEG built into the rotor and stator sections of μTC. Examination of the essentially different concepts of the μEG - micro turbocompressor (μTC) arrangement demonstrated that an independent power generation, high temperature, and high speed μGTE reliable operating can be ensured by different arrangements, e.g. with the rotor and stator sections of the electric generator placed between the appropriate turbine and compressor stage devices. In this case it is easier, compared to some other approaches, to evade an unpropitious effect on the μTC rotor strength characteristics (total stress level, critical velocities within the speed operation range, radial and axial deformations, etc) imposed by sizes and mass of the contact-free electromagnet couplings elements. This inference ensues, also, from the studies conducted [4, 5].