Abstract

Two component LDA velocity measurements have been made in three axial planes: just downstream of the Inlet Guide Vanes, (IGVs); the rotor and stators of a high speed aeroengine Compressor. At each axial stage circumferential measurements over a 22.5 degree arc were made in 0.25 degree interval steps at 21 radial heights between 2% and 98 %. The latter corresponds to high quality velocity measurement data less than 0.5 mm from the rig window. Overall, the data collection corresponds to over 10,000 2D velocity measurements with between 3-7000 velocity samples per spatial location. Some of these data are illustrated in the 3D contour plots shown of the measured IGV velocity magnitude and the flow angle. These data and other similar data at the other axial locations have been used to help develop new blade designs and validate Computational Fluid Dynamic codes. The sharp IGV wakes were resolved in 0.05 degree angular steps, each wake being some 0.4 degrees wide. The results show the very severe velocity gradient through the wake and the significant variation in flow angle in the boundary layer, (up to 20 % annulus height and above 80 % annulus height). The stability of the LDA system and the measurement rig was such that circumferential velocity profiles measured 12 days apart deviated at most by less than 0.5 %. Comparison with conventional instrumentation in measurement regions where this was valid has shown agreement to within 0.2 %.

© 1996 Optical Society of America