Laser Doppler Anemometry Measurements in an Axial Compressor Stage

The aim is to provide unsteady experimental data on the flowfield in a benchmark one-stage axial compressor, to improve the understanding of the flow features. The investigation is conducted with a two-component LDA, and 32 axial locations are surveyed, from the rotor inlet to the stator outlet. Because LDA is a nonintrusive device, data are obtained from the rotor row, providing information in a region difficult to explore with other techniques. Limitation of blade shadowing is addressed with an adjustment of the laser head orientation, which permits reaching any point inside the rotor. Furthermore, a dual probe orientation gives two sets of measurements yielding three velocity components. The dynamics of the rotor tip clearance vortex is discussed in the interrow gap. There is a strong interaction between this vortex and the rotor blade wake. Phase-averaged results show the unsteady flowfield and the rotor-stator interaction. The rotor wakes are cut up by the stator row and are visible until the exit of the axial zone of measurements. Their interaction with the stator blades boundary layers creates strong time-dependent flow structures, resulting in phase lags between the rotor wakes at the stator outlet. (Author)