Efficient Focusing of Aerosol Particles in the Microchannel under Reverse External Force: A Numerical Simulation Study

Focusing aerosol particles efficiently is of great significance for high-precision aerosol jet printing and detection of the airborne target. A new method was proposed herein to achieve the efficient focusing of aerosol particles in the microchannel by using a reverse external force. Considering the slip at the interface between the gas and the aerosol particle, a numerical model of the particle movement in the microchannel was established and simulations were conducted on the gas–particle two-phase flow in the microchannel under the effect of the reverse external force. The results showed that a suitable reverse external force in a similar order of magnitude to the Stokes force can dramatically increase the velocity difference between the particle and the gas, which significantly enhances the Saffman lift force exerted on the aerosol particle. Eventually, the aerosol particle can be efficiently focused at the center of the microchannel in a short channel length. In addition, the influence of the channel geometry, the magnitude, and the direction of the external force on the particle focusing was also studied. This work is of great significance for the precise detection of aerosol particles and the design of nozzles for aerosol jet printing.