Microscopic Visualization Investigation On Kinetic Characteristic Of Fine Particles

Researches on motion characteristic of fine particles had important significance to innovate and develop the theory of fine particles’multiphase flow. So the paper established an experimental system which combined high-speed digital video technique and microscopic visualization technique as an observation method, and some researches were done on this experimental system as below:1. Charge experiments to large glass ball and fine particles.Needle-plate discharge structure to charge large glass ball which was fixed in the middle of aerosol flow channel was used. It is found that large glass ball is positively charged in the positive DC discharge environment, and is negatively charged in the negative DC discharge environment. Besides,the method of how to calculate the charge of large glass ball and the datas of the charge in some conditions. Fine particles’ average charge with the median diameter of1.23μm and1.95μm was given which was measured by ELPI.2. Experimental research on fine particles’motion in the aerosol flow channelFine particles’motion in the aerosol flow channel was researched, related results are presented below:When the large glass ball fixed in the channel both large glass ball and fine particles are uncharged, fine particles flow over the large glass particle.When the large glass ball is charged and fine particles are uncharged, fine particles will be attracted by the large glass ball when they move near the large glass ball because of the dielectrophoretic force, and finally fine particles will be agglomerated on the surface of large glass ball.When the large glass ball and fine particles are charged same charges, to little charged fine particles, rejection generated by the electric field force Fqwill weaken the attraction between large glass ball and fine particles; to much charged fine particles, rejection generated by the electric field force Fq is enough to make fine particles flow over the large glass ball, for fine particles are rejected by the large glass ball,whenthe large glass ball and fine particles are charged opposite charges, the electric field force is attraction force, it will promote the attraction between the large glass ball and fine particles, with the increase of the large glass ball’s and fine particles’charge, the range of attraction increase accordingly.In addition, according to the experimental phenomenon and the force analysis of fine particles, the paper present a force model which contains dielectrophoretic force, drag force, electric force Fq and electric force Fq’. And magnitude analysis is done to fine particles in the aerosol flow channel by using the force model, and the paper analyze the fine particles’ motion characteristics by force analysis. It is found that the force model is applicable by comparing the results with the fine particles’ motion characteristics observed by experiments.