| Micro Gas Turbine is a type of small distributed generation device, which is widely used and meets the demands of different kinds of energy supplies. In this paper, a two-stage centrifugal compressor of a certain micro gas turbine for the automotive was studied in the CFD way.Using CFD software "NUMECA" to simulate a Krain's semi-shrouded centrifugal compressor, the numerical results were almost matched with the experimental ones, which showed the numerical ways were doable.Labview building-environment was used to write out the software for processing blade-data. It was used to smooth the leading and trailing edge of each blade section according to the origin blade data, and exports for different sorts of CFD software were provided. In a word, the software made the geometric modeling work more convenient.By taking two stages as a whole, numerical calculation was used to analysis this centrifugal compressor. And the performance curve at specified rotation speed was smooth, while efficiency was a little lower. Post-processing software "CFView" was used to see details of the flow filed, and it showed different loss in each parts. Situation in high-pressure stage was somewhat better than that in the low-pressure stage, and in each stage radial diffuser made the most loss, while axial diffuser and impeller were following behind. However, the flow through inlet guide vanes and return channel flow performed much better. In addition, each stage was calculated separately, and the performance curve confirmed that the high-pressure stage was a little better than the low one.Researching on the impeller and radial diffuser of the low-pressure stage, that how did blade angle and flow angle affect the aero-performance were studied. And the result showed that-within a certain limits, changing blade angle or inlet angle would weaken the vortex, reduce low velocity zone, increase efficiency and surge margin; meanwhile, there would be a little loss in the mass flow.
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