Computation of Erosion Potential of Cavitation Bubble in an Ultrasonic Pressure Field

Cavitation is the creation and collapse of a vapor cavity in a liquid. Cavitation can be produced by a sound field and this principle is employed in the ultrasonic vibratory cavitation device. The rapidly fluctuating applied pressure results in cavitation of the liquid. The pressure produced by the collapse of a vapor bubble can be determined by solving equations of bubble dynamics. The fundamental equation of bubble dynamics is the Rayleigh-Plesset- Noltingk-Neppiras-Poritsky equation popularly known as the RP equation. This equation does not account for the effect of liquid compressibility. Gilmore's equation, which considers liquid compressibility, can be used to obtain realistic estimates of bubble wall velocities at the end of bubble collapse. This paper discusses the numerical solution of Gilmore's equation to evaluate the bubble wall velocity at the end of bubble collapse and the pressure imposed on a solid surface from impingement of the resulting jet. The parameters affecting the growth and collapse of a single bubble is are studied. A discussion of results of cavitation damage experiments in sodium is also provided as a confirmation of the theoretical estimate of damage.