An Experimental Investigation of Thermal Effects in a Cavitating Inducer

TLDR

The study experimentally investigated how thermal effects influence leading‑edge cavitation development in an inducer using refrigerant R114. Using visualizations and pressure‑fluctuation spectra, the authors measured cavity‑length evolution versus cavitation parameter under various operating conditions, compared R114 to cold water, and assessed thermodynamic effects up to two‑phase breeding. Results show the B‑factor depends mainly on cavitation development, not on rotation speed or fluid temperature, corroborating classical entrainment theory, and suggest alternate‑blade cavitation onset is linked to a critical cavity length while rotating cavitation onset remains unclear.

Abstract

The thermal effects which affect the development of leading edge cavitation in an inducer were investigated experimentally using refrigerant R114. For different operating conditions, the evolution of the cavity length with the cavitation parameter was determined from visualizations. The tests were conducted up to two-phase breeding. The comparison of tests in R114 and in cold water allowed us to estimate the amplitude of the thermodynamic effect. The results show that the B-factor depends primarily upon the degree of development of cavitation but not significantly upon other parameters such as the inducer rotation speed or the fluid temperature, at least in the present domain of investigation. These trends are qualitatively in agreement with the classical entrainment theory. In addition, pressure fluctuations spectra were determined in order to detect the onset of cavitation instabilities and particularly of alternate blade cavitation and rotating cavitation. If the onset of alternate blade cavitation appeared to be connected to a critical cavity length, the results are not so clear concerning the onset of rotating cavitation.