Development of Flow Instability and Rotating Stall in a Multi-Stage Axial Copressor with Variable Guide-Vanes

Abstract : Many well-known investigations on flow instabilities of axial compressors have been conducted in low-speed research machines, often in a single stage configuration. It is at least not assured, that the results can be transferred directly to multi-stage compressors with compressible flow, therefore measurements in machines of this type are of considerable practical interest. These machines, however, pose a lot more problems in realisation, operation and measuring techniques. They have to be of robust and elaborate design and manufacture to withstand high rotational speed and to avoid problems with blade vibrations and critical rotor speed. They need even as model machines with reduced size driving power of several hundred kW up to the MW range, preferably with variable speed.