Measurements of the Flow From a High-Speed Compressor Rotor Using a Dual Probe Digital Sampling (DPDS) Technique

The flow from a high-speed rotor in a rotor-first arrangement has been measured using a “dual-probe, digital sampling (DPDS)” technique. The flow field was found to be steady in rotor coordinates (periodic in machine coordinates) outside the rotor wake, and three components of velocity and the pressure field were determined in this area. The wake regions were unsteady. In these regions the measurements based on ensemble averages of multiple samples did not follow the behavior established during calibration in steady uniform free-jet flow, except near the wake center. The broadening of the wake and three-dimensional effects in the flow field were measured at reduced throttle and increased speeds. The results serve to illustrate the potential of the measurement technique, on which the emphasis of the presentation is placed.