This paper presents the results of an aerodynamic analysis of a small-scaled transonic centrifugal compressor for micro turbojet engine (TJE) applications. The analysis was conducted using a CFD model validated by experimental data collected for the gaged JetCat P200-RX micro-TJE. The loss coefficients of the impeller, vaned diffuser and deswirler were estimated for 4 design points corresponding to 70%, 80%, 90% and 100% rotation speeds to perform the loss balance diagram. The flow angle spanwise variation demonstrated an intensive flow separation zone at the top 25% of the vaned diffuser span due to the pressure shock appearance. It was shown that the main source of the losses in the investigated compressor is the deswirler due to non-optimal flow turning conditions. The diffuser loss coefficient was estimated as 0.18 at the compressor full load.

The paper presents the results of the investigation of the part span shroud effect on the transonic axial compressor operational map. The objective of the paper is a 4.5-stage transonic low-pressure compressor of the aero-derivative gas turbine engine. The study was performed with using 3D RANS calculations via Ansys CFX commercial solver. The numerical model was validated with experimental data for 4 speedlines. The standard k-ɛ turbulence model demonstrated good agreement with the experimental data while SST model unexpectedly overpredicted mass flow rate. The strong effect of the mesh aspect ratio in the radial direction was observed. A significant decrease of the mass flow rate and the compressor efficiency was shown for the rotation speed range 85% – 95%. The maximum mass flow rate decreasing was estimated as 3.5%, maximum efficiency deterioration – 1.5%.