ASPIRATING PROBE MEASUREMENTS OF THE UNSTEADY TOTAL TEMPERATURE-FIELDDOWNSTREAM OF AN EMBEDDED STATOR IN A MULTISTAGE AXIAL-FLOW COMPRESSOR

The results from the area traverse measurements of the unsteady total temperature using a high-response aspirating probe downstream of the s econd stator of a three-stage axial flow compressor are presented The measurements were conducted at the peak efficiency operating point. Th e unsteady total temperature data are resolved into deterministic and unresolved components. Hub and casing regions have high levels of unst eadiness and consequently high levels of mixing. These regions have si gnificant levels of shaft resolved and unresolved unsteadiness. Compar isons are made between the total temperature and the total pressure da ta to examine the rotor 2 wake characteristics and the temporal variat ion of the stator exit flow. Isentropic efficiency calculations at the midpitch location show that there is about a 4 percent change in the algebraically averaged efficiency across the blades of the second roto r and if all the rotor 2 blades were behaving as a ''best'' blade, the improvement in efficiency would be about 1.3 percent. An attempt is m ade to create a composite pow field picture by correlating the unstead y velocity data with temperature and pressure data.