A Method for Calculating Ultrasonic Coagulation of PM2.5 Particles in Vortex and Turbulent Acoustic Flows

Abstract

We propose a method for calculating the kinetics of ultrasonic coagulation of PM2.5 during fine gas cleaning that provides an order of magnitude higher calculation performance. Increased productivity is achieved through the proposed and justified method of reducing the original three-dimensional problem to a two-dimensional one. The proposed reduction method is based on the fact that the time of complete rotation of vortex acoustic flows turns out to be much shorter than the characteristic coagulation time during fine gas cleaning. This makes it possible to present the fractional composition of aerosol particles as a function of two stream functions instead of three coordinates. Calculations carried out using the proposed method make it possible to identify the possibility of increasing the efficiency of coagulation in three-dimensional flows due to the following mechanisms: a local increase in concentration caused by the inertial transfer of particles to the periphery of three-dimensional vortices in the gas phase, increasing the frequency of particle collisions due to three-dimensional turbulent disturbances in ultrasonic fields with a high amplitude of oscillatory velocity (more than 10 m/s), and increasing productivity and ensuring the possibility of continuous implementation of the process in flow mode due to the transfer of particles between the streamlines of the main vortices initiated by ultrasonic vibrations as well as due to external flows perpendicular to the plane of the vortices in three-dimensional space. The developed set of programs for implementing calculations can be used in the design of gas cleaning equipment.