Research On The Model Of Micro-Particle Collision And Coagulation

Particle pollution in the air has done harm to the health of human andquality of life. Numerous cities have started to measure and control particles. Someinvestigates demonstrate that the smaller particles are, the more dangerous they willbe. Thus, the research on the change of particle size is a significant section for thecontrol of particle pollution. The coagulation of particles leads to the change ofparticle size. Many previous investigators considered that when particles collide theywill coalescence to one for sure which did not match the fact.In the process of collision, the van der Waals force, elastic deformation force,electrostatic force, Stokes drag force, lubrication force and gravity are exerted on theparticles. The collision consists of the stages of compression and rebound. In thispaper we establish and solve the dynamical equations to achieve the collisionefficiency according to the model of particle coagulation. Then, changing thecollision angle, ratio of size and force exerted on the particle, we can obtain thecollision efficiencies at different collision angles, ratio of size and force exerted onthe particle. It is shown that the collision efficiency decreases with increasing theparticle size and ratio of size, but increases with increasing collision angle. Also, thelike charges make the collision efficiency decrease while the unlike charges have theopposite effect. New expressions for the collision efficiencies are brought forward inthe current paper. After modify the coagulation rate by the collision efficiency, thecoagulation rate is smaller than that before modification.The collision between two particles is extended to that between a particle and thewall. The method and procedure of calculation are same with that used in thecollision between two particles. It is denoted that the attachment efficiency has thesame change trend with the collision efficiency, and the deposition after modificationbecomes more difficult.