EXPERIMENTAL STUDY OF SUBMICRON PARTICLES' MOTION IN THE EFFECT OF PARTICLE-SINK

As particulate air pollution has aroused the universal concern of the public, the motion and diffusion law as well as the distribution rule of suspended particles have become research focuses. The suspended particles in air are discrete which are different from continuum medium, and thus the model of particle motion are different from that of continuous fluid. To ascertain the model of particle motion is a critical issue in the research of ambient particulate matter. This paper concentrates on the movement of submicron particles in still air where the particle-sink exists. In this experimental study, submicron particles were generated by combustion, particle-sink was simulated through electrostatic adsorption device, and particles' movements at different intensities of particle-sinks were measured by PIV and LDV. The experimental results show that movements of particles in still air without sink are Brownian motion, and if there is a sink, particles move to the sink at variable velocities which varied inversely as the distance to the sink. It turns out that particles' movements around sink are analogous to that of continuum flow. Also, an empirical formula of particle's twodimensional velocity distribution is given on the basis of PIV experimental data, which shows the motion of particle in small space does not satisfy the continuity equation. Meanwhile, experiments in a bigger space were performed by LDV technique, and the result is identical with previous experimental outcome. Therefore, according to this study, a hypothesis is presented as follows:a non-pneumatic-conveying air purify technology base on sink's action and particle disperse is feasible.