The flow field within the rotor of a transonic axial compressor has been computed and compared to measurements obtained with an advanced laser velocimeter. The compressor was designed for a total pressure ratio of 1.51 at a relative tip Mach number of 1.4. The comparisons are made at 100 percent design speed (20,260 RPM) with pressure ratios corresponding to peak efficiency, near surge, and wide open discharge operating conditions. The computational procedure iterates between a blade-to-blade calculation and an intrablade through flow calculation. Calculated Mach number contours, surface pressure distributions, and exit total pressure profiles are in agreement with the experimental data demonstrating the usefulness of quasi three-dimensional calculations in compressor design.

The flow field ahead, within, and behind the rotor of a transonic axial compressor designed for a total pressure ratio of 1.51 at a relative tip Mach number of 1.4 has been studied in detail using an advanced laser velocimeter. The tests were carried out at 70 and 100 percent design speed (20,260 rpm) and equivalent mass flows corresponding to the point of maximum isentropic efficiency. The tests yielded quite complete data on the span- and gap-wise velocity profiles, on the three-dimensional shock waves in and outside of the rotor blade channels, and on the blade wakes. Some of the experimental results will be submitted, discussed, and compared to corresponding analytical data of a through-flow calculation. The comparison reveals considerable discrepancies inside the blade row between the two-dimensional calculation and the experiments primarily due to the loss and deviation correlations used, as well as to the distribution of losses and flow angles inside the blade channels.

In order to verify a new controlled diffusion blade design concept, the stator of an existing transonic axial compressor stage was redesigned. Stator and equivalent cascade tests revealed the potential of such blades for a considerably higher aerodynamic loading than it has been applied up to now. The design procedure is described, and the results of plane cascade and stage testing are submitted, including performance analysis of both cascade and stator blade sections, at design and off-design operating conditions. The blade profile shapes and cascade geometries were calculated by means of an inverse, two-dimensional method taking also into account the axial velocity density ratio (AVDR). This design concept is essentially based on prescribed blade pressure distributions, which are optimized with respect to the blade boundary layer development. The flow phenomena are illustrated by means of loss and flow turning investigations, blade pressure distributions, and laser velocimetry data. The test results reveal that the two-dimensional approach applied is quite promising for the three-dimensional blade design. Finally, overall and blade element performance comparisons between the original NACA 65 profiled stator and the redesigned one demonstrate the favorable flow behavior of the new stator, as well as the great potential of the controlled diffusion blade concept.

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