Direct simulation of inhalable particle motion and collision in a standing wave field

Abstract

Motion of inhalable particles (PM10) under the effect of acoustic standing wave was numerically studied, and the inter-particle collision rate was investigated based on the direct simulation Monte Carlo (DSMC) method. The results show that the particles convergence rapidly, generating two particle number concentration peaks in a wavelength range along the wave propagation direction. Considering the inter-particle collision, it is found that when the particle size and number concentration keep constant, the collision rate first increases and then decreases with the increase of the frequency. Hence there is an optimal frequency that corresponds to the highest collision rate. As the sound intensity level increases, the collision rate increases monotonically. In cases with the same acoustic wave, the collision rate increases with the particle number concentration. The particle size is also an important factor that strongly affects the collision rate. The large inhalable particles collide more intensively than the small ones.