Experimental investigation on the particle capture by a single fiber using microscopic image technique

Four kinds of solid particles were captured by a single fiber. The particles included two kinds of fly ash particles and two kinds of ceramic particles under three different types of charging pretreatment. The single fiber was fixed across a square cross-section glass tube. A standard continuous aerosol generator was used to disperse particles to generate a uniform aerosol. The aerosol particles from the generator were tribocharged, polarized or charged, and then passed across the fiber. A microscope and a CCD camera were used to observe the capturing process and the shape distribution of dendrites. The results showed that the deposited particles developed in different ways. In the tribocharged case, dendrite formation can be classified into three distinct stages. In the prepolarized case, straight chains were formed at a uniform spacing interval, and had high binding intensity to support very long chains. Even though the long chains fell over they still had high capturing efficiency. In the precharged case, some straight chains with some branches were formed, but their binding intensity was low and they easily fell over and broke. The results also showed how the particle diameter and shape influenced the formation of dendrites and chains.