Possibility of Quantitative Prediction of Cavitation Erosion Without Model Test

Abstract

A scenario for quantitative prediction of cavitation erosion was proposed. The key value is the impact force/pressure spectrum on a solid surface caused by cavitation bubble collapse. As the first step of prediction, the authors constructed the scenario from an estimation of the cavity generation rate to the prediction of impact force spectrum, including the estimations of collapsing cavity number and impact pressure. The prediction was compared with measurements of impact force spectra on a partially cavitating hydrofoil. A good quantitative agreement was obtained between the prediction and the experiment. However, the present method predicted a larger effect of main flow velocity than that observed. The present scenario is promising as a method of predicting erosion without using a model test.

Cloud cavitation control for lithotripsy using high intensity focused ultrasound

“…Numerous experimental studies (Kato et al 1996;Knapp 1955;Konnno et al 2002;Reisman and Brennen 1996;Reisman et al 1998;Soyama et al 1992) and analytical/numerical studies (Chahine and Duraiswami 1992;Brennen 1988, 1989;Mørch 1981;Omta 1987;van Wijngaarden 1964;Brennen 1995, 1999) have been conducted to investigate the dynamics of cloud collapse and to calculate the pressure generated in the cloud. The indirect experimental measurements of a maximum pressure inside a cloud of up to 10 8 ϳ10 9 Pa have been reported (Kato et al 1996;Reisman et al 1998). Shimada et al (2000) used a numerical model for the spherical bubble cloud, considering the individual oscillating bubbles, to investigate a converging shock wave within the cloud.…”

Unraveling the Geometry Dependence of In-Nozzle Cavitation in High-Pressure Injectors

“…For more than a century, cavitating flows have attracted researchers due to the damaging effects to fluid-handling devices, and the technological applications in the mechanical, chemical engineering, and biomedical fields12345678910. On the one hand, cavitation causes stress erosion at liquid/solid interfaces345678, ranging from minor damages over the span of long-time operations, to disastrous major damages in a relatively short period of time3. On the other hand, it can also facilitate mixing in colloidal suspension, surface cleaning, improving heat and mass transfer34, and enhancing conventional chemical reactivity910.…”

An Erosion Aggressiveness Index (EAI) Based on Pressure Load Estimation Due to Bubble Collapse in Cavitating Flows Within the RANS Solvers

“…Equation (9) predicts that the impact pressure on the material surface is proportional to the square of the flow velocity (√/ .Dα/Dt); as the erosion rate is proportional to the square of the impact pressure, therefore it is predicted that the erosion rate would be proportional to the fourth power of the flow velocity; this finding qualitatively agrees with the experimental evidence that the erosion rate is proportional at least to the flow velocity to the fourth power; equation (9)takes into account also the effect of non-condensable gas content in the liquid by indirectly affecting the maximum bubble radius. Equation (9) also indicates that the erosion rate depends on the initial bubble size as it affects R max and also on the initial bubble number density distribution as reported by Kato et al [12].…”

“…Kato et al [12] were among the first to propose an analytic model to compute material erosion due to cavitation; their model was based in estimating the impact force due to bubble collapse and the frequency of bubble collapses on the material surface. The number density distribution of the bubble size was taken into account in calculating the cumulative impact force due to synchronous bubble collapse; the authors pointed out the importance of the number density distribution on predicting erosion.…”