Design and CFD analysis of centrifugal compressor for a microgasturbine

Purpose - This paper aims to show how a good compressor can be designed and modeled with CFD steady models and to explain reasons for discrepancies between experiment (1 D design) and 3D CFD analysis. Design/methodology/approach - A model with only one impeller channel was used to compare 1D design data, which were obtained from centrifugal compressor design code, written and developed by the authors. The often used model for CFD analysis of turbo machinery known as "frozen-rotor" model, only yields satisfying results for efficiency and pressure ratio, at and near the point of best efficiency. For this case, the static pressure shows a nearly uniform circumferential distribution at the inlet of the diffuser, which numerically leads to more homogeneous flow rates through the single vane channels, and thus to a more realistic time averaged flow distribution. Findings - The numerical results with respect to performance data showed quite good agreement with experimental data at and near the operating point of best efficiency. Originality/value - This paper offers a combined 1 D and 3D numerical approach in turbo machinery design, especially in radial compressible turbo machines design.