Three-Dimensional Numerical Model of Ultrasonic Coagulation of PM2.5 Aerosol Particles in Vortex Acoustic Flows

The effectiveness of existing dust collectors for PM2.5 particles, which pose a significant health hazard and are found in areas previously considered free of such particles, is close to zero. One effective way to enlarge particles to improve the efficiency of existing dust collectors is forced ultrasonic coagulation of aerosols. However, ultrasonic coagulation is effective only starting with particle sizes of 5–10 µm and more. Therefore, the studies conducted by the authors are aimed at finding and theoretically substantiating the possibilities of increasing the efficiency of PM2.5 coagulation by creating conditions for the formation of three-dimensional nonlinear effects—vortex flows and turbulent disturbances. A numerical model of ultrasonic coagulation is proposed taking into account these effects. The numerical analysis of the model using PM2.5 aerosol as an example allowed us to establish that coagulation is most effectively realized in resonant acoustic fields, in which vortex flows and turbulent disturbances have maximum speed. The presence of three-dimensional turbulent disturbances leads to the fact that the coagulation efficiency reaches almost 100% at a sound pressure level of no more than 165 dB.