Scaling of Cavitation Erosion Progression with Cavitation Intensity and Cavitation Source

A simple mathematical expression is presented to describe cavitation mean depth of erosion versus time for cavitating jets and ultrasonic cavitation. Following normalization with a characteristic time, t*, which occurs at 75% of the time of maximum rate of erosion, and a corresponding material characteristic mean erosion depth, h*, the normalized erosion depth is related to the normalized time by 1 1.2 2 1 e . − − = − + t h e t This was obtained by conducting systematic erosion progression tests on several materials and varying erosion field intensities. Both a modified ASTM-G32 method and DYNAFLOW’s cavitating jets techniques were used and the jet pressures were varied between 1,000 and 7,000 psi. The characteristic parameters were obtained for the different configurations and the correlation was found to be very good, exceeding an R of 0.988 for all cases. Relationships between these parameters and the jet pressure were obtained and resemble familiar trends presented in the literature for mass loss. The study allowed a comparative evaluation and ranking of the various materials with the two accelerated erosion testing methods used. While several materials ranked the same way with the different erosion intensities and testing method, the relative ranking of erosion resistance of some materials was seen to be dependent on the cavitation intensity.