Simultaneous Cavitation Susceptibility Meter and Holographic Measurement of Nuclei in Liquids

Cavitation Susceptibility Meter (CSM) and holographic measurements of cavitation nuclei distributions are compared in this paper. The CSM optically detects cavitation in water samples flowing through a venturi and relates the unstable nuclei concentration to the applied tension in the fluid. A ruby laser holographic system measures the nuclei size distribution directly. Microbubbles have been used as the dominant nuclei source. The data from the two detection schemes are correlated by accounting for the dynamic response of the cavities in the venturi throat. The active nuclei distributions predicted by the holographic data compare favorably with those measured by the CSM. Both detection method show that the nuclei concentration rises approximately exponentially as the applied tension is increased and then, with further reduction in the pressure, tends to a nearly constant maximum due to the shortage of remaining cavitatable nuclei. The CSM consistently underestimates the c...