Cavitation in compressible supercritical carbon dioxide

Abstract

The threshold pressure to induce cavitation in supercritical carbon dioxide is analysed with Rayleigh theory, and the surface tension and the viscosity of the fluid are ignored. It is found that the acquired ultrasonic pressure is similar to the critical pressure of the fluid due to the absence of vapour pressure. Based on a liquid state equation and the available physical parameters, a new state equation for supercritical carbon dioxide is proposed for solving the Gilmore equation with improved accuracy. The fourth order Runge–Kutta method is adopted to calculate the bubble-wall motions and the results show that a bubble in supercritical carbon dioxide may collapse and the characteristics of its motion are similar to cavitations in ordinary liquid. The compressibility of supercritical fluid should be considered when studying its cavitations, and our results show that the collapse intensity decreases greatly when the compressibility of supercritical fluid is considered.