Determination of ultrasonic effect mode providing formation of cavitation area in high-viscous and non-Newtonian liquids

Abstract

The article presents the phenomenological model of the formation of cavitation area in high-viscous and non-Newtonian liquids. Proposed model is based on the study of the formation of cavitation area as a whole but taking into account the main effects and phenomena occurring inside this area. The analysis of the model allows revealing optimum intensities of the ultrasonic influence, which are necessary for the appearance of the mode of developed cavitation for liquids different in their rheological properties. The analysis of the model lets determining, that optimum intensities of the influence for the most of liquids does not exceed 40 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at the frequency of 22 kHz, with the exception of dilatant fluids, for which intensity of influence can achieve 100 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . As a result of the model analysis it is found out the change of optimum intensity for non-Newtonian liquids with the course of time induced by the relaxation of viscosity. Increase or decrease of the intensity, which is necessary for the formation of cavitation area, achieves 20 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . Obtained results can be applied for the choice of power modes of the ultrasonic technological equipment and the control of the process of cavitation treatment of media with different rheological properties.