Modelling of free radicals production in a collapsing gas-vapour bubble.

This paper deals with a model linking bubble dynamics under an acoustic pressure field and production of free radicals in the resulting collapses of this bubble. The bubble dynamics model includes interdiffusion of gas and vapour in the bubble as well as evaporation or condensation at the interface, and it assumes uniformity of the internal pressure and perfect gas law for the gas vapour mixture. At the maximum compression of the bubble, all the reactions of dissociation which can occur are assumed at thermodynamic equilibrium. The local composition (especially in free radicals) in the bubble is then calculated by an algorithm based on free energy minimization using the information concerning the maximum compression provided by the bubble dynamics model resolution. Using this model a comparison of free radicals production has been made for two different driving frequencies (20 kHz and 500 kHz), and at given bubble radius and acoustic pressure, an optimum of liquid bulk temperature has been derived for the production of free radicals very similar to the experimental one concerning oxidation reactions in aqueous phase.

[1]  Andrea Prosperetti,et al.  Erratum and Comments on ``Nonlinear oscillations of gas bubbles in liquids: An interpretation of some experimental results'' [J. Acoust. Soc. Am. 73, 121-127 (1983)] , 1984 .

[2]  Andrea Prosperetti,et al.  The thermal behaviour of oscillating gas bubbles , 1991, Journal of Fluid Mechanics.

[3]  Anthony I. Eller,et al.  Rectified Diffusion during Nonlinear Pulsations of Cavitation Bubbles , 1963 .

[4]  T. Lepoint,et al.  What exactly is cavitation chemistry , 1994 .

[5]  Werner Lauterborn,et al.  Numerical investigation of nonlinear oscillations of gas bubbles in liquids , 1976 .

[6]  Andrea Prosperetti,et al.  Thermal effects and damping mechanisms in the forced radial oscillations of gas bubbles in liquids , 1977 .

[7]  Andrea Prosperetti,et al.  Nonlinear oscillations of gas bubbles in liquids: An interpretation of some experimental results , 1983 .

[8]  M. Entezari,et al.  Effect of frequency on sonochemical reactions II. Temperature and intensity effects , 1996 .

[9]  Lawrence A. Crum,et al.  The polytropic exponent of gas contained within air bubbles pulsating in a liquid , 1983 .

[10]  Andrea Prosperetti,et al.  Numerical integration methods in gas‐bubble dynamics , 1989 .

[11]  M. Entezari,et al.  Effect of frequency on sonochemical reactions. I: Oxidation of iodide , 1994 .

[12]  Joseph B. Keller,et al.  Damping of Underwater Explosion Bubble Oscillations , 1956 .

[13]  D. Hsieh.  Some Analytical Aspects of Bubble Dynamics , 1965 .

[14]  Andrea Prosperetti,et al.  Bubble dynamics in a compressible liquid. Part 2. Second-order theory , 1987, Journal of Fluid Mechanics.

[15]  Andrea Prosperetti,et al.  A theoretical study of sonoluminescence , 1993 .

[16]  Andrea Prosperetti,et al.  Bubble phenomena in sound fields: part one , 1984 .

[17]  Michael J. Miksis,et al.  Bubble Oscillations of Large Amplitude , 1980 .

[18]  S. Chandrasekaran,et al.  Modelling of a batch sonochemical reactor , 1994 .

[19]  H. G. Flynn.  Cavitation dynamics. I. A mathematical formulation , 1975 .

[20]  K. Suslick,et al.  On the origin of sonoluminescence and sonochemistry. , 1990, Ultrasonics.

[21]  Milton S. Plesset,et al.  Theory of Rectified Diffusion of Mass into Gas Bubbles , 1961 .

[22]  Andrea Prosperetti,et al.  Nonlinear bubble dynamics , 1988 .

[23]  Andrea Prosperetti,et al.  Bubble dynamics in a compressible liquid. Part 1. First-order theory , 1986, Journal of Fluid Mechanics.

[24]  Robert I. Nigmatulin,et al.  Dynamics, heat and mass transfer of vapour-gas bubbles in a liquid , 1981 .