A Low-Speed Compressor Test Rig for Flutter Investigations

Abstract

A test facility for aeroeolastic investigations has been set up at the chair of Aero Engines at the Technische Universität Berlin. The test rig provides data for tool and code validation, and is used for basic aeroelastic experiments. It is a low-speed wind tunnel, which allows free and controlled flutter testing. The test section contains a linear cascade with eleven compressor blades. Nine of them are elastically suspended. The paper presents a detailed description of the test facility results to evaluate the overall flow quality alongside an aeroelastic model to predict the flutter velocity and critical interblade phase angles (IBPAs). Furthermore, chordwise pressure distributions, measured with traveling wave (TW) mode experimental tests, are presented. These measurements have been carried out for a wide range of IBPAs and have been compared to numerical results. Hot-wire anemometry has been applied to examine the inlet flow for several Mach numbers and Reynolds numbers. The results show small turbulence intensities. The blade surface pressure distribution and the flow field of the blade's suction and pressure sides have been obtained by oil flow visualization.