Thermodynamic Effect on a Cavitating Inducer—Part II: On-Board Measurements of Temperature Depression Within Leading Edge Cavities

Temperature depression within the leading edge cavities on a space inducer is measured in Refrigerant 114 using miniature thermocouples mounted on the rotating blades. Time-averaged values of cavity temperature depression are determined all along the descent in cavitation number and correlated with the extent of cavities. In addition to mean values, temperature fluctuations are analyzed with respect to the onset of cavitation instabilities, namely, alternate blade cavitation and supersynchronous rotating cavitation. Temperature spectra relative to a rotating frame of reference are compared with pressure spectra obtained in a fixed frame of reference. Temperature oscillations issued from different blades are compared, and phase shifts between consecutive and opposite blades are evaluated in the case of the supersynchronous instability regime.