Measurements of the Pressure and Velocity Distribution in Low-Speed Turbomachinery by Means of High-Frequency Pressure Transducers

The flow in a low-speed, single-state compressor with a very high blade loading has been measured using a two-probe arrangement. The measuring technique and data reduction procedure described have been especially adjusted for application in low-speed turbomachinery. Those machines show only small pressure fluctuations in the flow downstream of the rotor, for which specific requirements concerning the measuring technique have been taken into account. The probes used contain unsteady pressure transducers and simulate an unsteady multisensor pressure probe. This technique proves to be suitable for applications in low-speed turbomachinery. The measurements are based on phase-locked ensemble averages of multiple samples, where the data are acquired using a simple and convenient experimental setup. This allows the velocity and pressure distribution of the flow to be determined in rotor coordinates. The results show the flow field and the loss distribution of an aero-dynamically highly loaded rotor at design flow rate.