Scaling study of cavitation pitting from cavitating jets and ultrasonic horns

Abstract

International audienceCavitation erosion prediction and characterization of cavitation field strength are of interest to industries suffering from cavitation erosion detrimental effects. One means to evaluate cavitation fields and materials is to examine pitting rates during the incubation period, where the test sample undergoes localized permanent deformations shaped as individual pits. In this study, samples from three metallic materials, an Aluminum alloy (Al 7075), a Nickel Aluminum Bronze (NAB) and a Duplex Stainless Steel (SS A2205) were subjected to a vast range of cavitation intensities generated by cavitating jets at different driving pressures and by an ultrasonic horn. The resulting pitted sample surfaces were examined and characterized with a non-contact 3D optical scanner and the resulting damage computer-analyzed. A statistical analysis of the pit population and its characteristics was then carried out. It was found that the various cavitation field strengths can be correlated to the measured pit distributions and that two characteristic quantities: a characteristic number of pits per unit surface area and unit time, and a characteristic pit diameter or a characteristic pit depth can be attributed to a given "cavitation intensity level". This characterization concept can be used in the future to study the cavitation intensity of the full scale and to develop methods of full scale predictions based on model scale erosion data

Modeling of surface cleaning by cavitation bubble dynamics and collapse

“…In order to examine removal of a layer of material coating on a solid substrate, we use a similar approach to that we used to study cavitation pitting on materials [14][15][16]. To do so, either a synthetic load representing the forces generated by the bubble dynamics or direct coupling between the fluid computations and the structure computations at each time are applied.…”

“…Industrial scale implementation of ultrasonic cleaning covers many applications including cleaning of machine parts, jewelry, surgical instruments, laboratory equipment, textile, oil pipes, filter membranes, and semiconductor substrates [5][6][7][8][9][10]. Submerged liquid cavitating jets are also widely used for cleaning, cutting, drilling [11][12][13], and for controlled evaluation of materials' resistance to cavitation erosion [14][15][16]. Cavitation intensity produced by submerged jets can be varied in a very wide range through adjustment of the jet velocity, diameter, angle and standoff distance relative to the exposed surface, and the ambient pressure in which they are discharged [15].…”

Analysis of the cavitating flow induced by an ultrasonic horn – Experimental investigation on the influence of actuation phase, amplitude and geometrical boundary conditions

“…Jayaprakash et al investigated the influence of ultrasonic cavitation on different materials according to the ASTM G32 [8] norm for tests of "cavitation resistivity" [7]. They analyzed the damage of cavitation by Pitting Tests.…”

Power law modeling of acoustic cavitation erosion: the hemispherical pit model

“…Modeling of cavitation erosion before the emergence of RCE often utilized metrics such as erosion rate [4][5][6][7], incubation period [8], mean depth of erosion/penetration (MDE/MDP) [9], mean depth of erosion/ penetration rate (MDER/MDPR) [10,11], and mass/volume loss [12,13]. The erosion rate is calculated through numerical differentiation of mass loss data and due to the difficulty in continuous monitoring of the mass loss is inherently inaccurate.…”