Mathematical Simulation of the Influence of Acoustic on the Efficiency of PM 2.5 Coagulation

The particles of micron and submicron sizes (PM 2.5 and less) in gas environments pose a significant danger to humanity due to the emergence of specific and very dangerous diseases of the cardiovascular, respiratory, and immune systems of the human body. Such particles are the most difficult to detect; therefore, their effects on human health have only been discovered in recent decades. Classical ultrasonic coagulation by sinusoidal action turns out to be ineffective for PM 2.5 due to the peculiarities of the physical mechanisms of hydrodynamic and orthokinetic interaction realized in gaseous media. This article presents a theoretical justification for choosing ways to increase the efficiency of ultrasonic coagulation of PM 2.5 by creating special conditions under which nonlinear disturbances of the velocity and pressure of the gas phase in the ultrasonic field occur. The authors performed simulations of ultrasonic coagulation under nonlinear disturbances of the velocity (vortex) and the pressure (shock waves), which has numerical difficulties due to the instability of existing methods. As a result of the numerical analysis, the possibility of increasing the coagulation rate of particles in the submicron size range up to limit values (13 times due to nonlinear pressure disturbances, and an additional increase of at least 2 times due to aerosol compaction in the vortex field of gas velocity) was shown.