Unsteady Measurements in the Rotor Relative Frame

O. Burkhardt, W. Nitsche,

Technical University of Berlin
Institute of Aeronautics and Astronautics
Marchstr. 12, Sekr. F2, 10587 Berlin, Germany

M. Goller, M. Swoboda, V. Guemmer,

Rolls-Royce Deutschland Ltd. and Co. KG
Eschenweg 11, 15827 Dahlewitz, Germany

H. Rohkamm, and G. Kosyna

Technical University of Braunschweig, Pfkiderer-Institute
Langer Kamp 6, 38106 Braunschweig, Germany

Abstract Unsteady measurements were performed on rotor and stator blades of a highly – loaded 1.5-stage, low-speed axial compressor cascade using dynamic skin-friction measurement techniques. The project focusses on advanced 3D compressor blade design and has the potential to improve tip-clearance fbw control at high loading by introducing different advanced unsteady measurement techniques. As an alternative to typical hot films, a novel surface hot wire with a better dy­namic response was used. This device is capable of measuring the effects of unsteady aerodynamics in turbo machinery components. The results show the inflience at different operating points (mass flaw) and rotor-stator interactions on the boundary layer transition development using statical values as well as analysis functions such as power spectrum and correlation. In addition, prelim­inary results of the unsteady boundary layer development at rotating stall are being presented.

Keywords: Rotor-stator interaction; Unsteady aerodynamics; Boundary layer transition; Mea­

surements in rotating frame.


K. C. Hall et al. (eds),

Unsteady Aerodynamics, Aeroacoustics and Aeroelasticity of Turbomachines, 603-614. © 2006 Springer. Printed in the Netherlands.

0. Introduction

The boundary-layer transition process on turbo machine blades is mainly in – fbenced by periodically incoming wakes, generated by an upstream blade row. Investigation by Adamczyk [1] has shown that the total pressure loss of a com­pressor blade row can be reduced if the incoming wakes mix out after rather than before the following blade row. Preliminary measurements, e. g. [2], were carried out using simple and suitable set ups to investigate interactions be­tween rotating and stationary blade rows. Traversable bars with diameters of 3 mm placed in front of a linear stator cascade were used to simulate and in­vestigate wake-induced transition. In the last few years measurements were directly conducted on real turbo machines with single or multi-stage blade rows. Detailed boundary layer measurements on stator vanes were done us­ing surface hot film sensors. However, until now simultaneous data acquisition using a high number of sensors has never been carried out, especially on rotor blades due to the complexity of the setup. Such measurements were performed in this project using a telemetry-system and a 16-channel miniature constant – temperature anemometry ring.

1. Setup

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