MATHEMATICAL MODEL OF THE PROCESS OF MULTISTAGE FRAGMENTATION OF DROPLETS IN AN ULTRASONIC FIELD

Consideration is given to the problem of creation of fi ne aerosols by a novel method consisting in the droplets of a liquid breaking up in a series of antinodes of a powerful ultrasonic fi eld. This makes it possible to obtain an aerosol cloud with a droplet size under 50 μm with a high effi ciency at relatively low energy expenditures. A mathematical model of multistage spraying of droplets in an acoustic fi eld has been proposed, which is based on the energy approach with hydrodynamic criteria, with the Weber number and the acoustic Bond number being basic ones. Critical conditions have been determined for the breakup of droplets, and also their limiting dimension. Possible mechanisms of disintegration of droplets, as they pass successively through the antinodes of the ultrasonic fi eld, have been described depending on the initial size of the droplets and the velocity of their motion, the surface tension of the liquid in the droplets, and acoustic pressure. From the results of measurements of the dispersion parameters of the aerosol obtained in the process of multistage spraying of the liquid in the acoustic fi eld, free parameters of the mathematical model of the process have been determined.
Consideration is given to the problem of creation of fi ne aerosols by a novel method consisting in the droplets of a liquid breaking up in a series of antinodes of a powerful ultrasonic fi eld. This makes it possible to obtain an aerosol cloud with a droplet size under 50 μm with a high effi ciency at relatively low energy expenditures. A mathematical model of multistage spraying of droplets in an acoustic fi eld has been proposed, which is based on the energy approach with hydrodynamic criteria, with the Weber number and the acoustic Bond number being basic ones. Critical conditions have been determined for the breakup of droplets, and also their limiting dimension. Possible mechanisms of disintegration of droplets, as they pass successively through the antinodes of the ultrasonic fi eld, have been described depending on the initial size of the droplets and the velocity of their motion, the surface tension of the liquid in the droplets, and acoustic pressure. From the results of measurements of the dispersion parameters of the aerosol obtained in the process of multistage spraying of the liquid in the acoustic fi eld, free parameters of the mathematical model of the process have been determined.
Author:  Olga B. Kudryashova, Andrey V. Shalunov, Viktor A. Nesterov, and Sergey A. Terentiev
Keywords:  aerosol, fragmentation of droplets, ultrasonic fi eld, mathematical model
Page:  533