Effects of wall vibration on particle deposition and reentrainment in aerosol flow

The simultaneous phenomenon of particle deposition and reentrainment on a vibrating wall has been studied experimentally. Aerosols that were generated by dispersing alumina powder, of size 3.8-12.5 mum mass median diameter, were transported into a vertical glass tube equipped with a vibration motor. The formation process of the particle deposition layer in the tube was observed through a digital video camera with a zoom lens. The experimental results showed that wall vibration was effective to enhance particle reentrainment. Critical flow velocity for the case of no particle layer formation decreased with increasing vibration acceleration and/or particle diameter. In contrast, at a velocity below the critical value, the wall vibration increased the amount of particles deposited on the wall. The critical condition for no particle layer formation under wall vibration was explained using a moment balance model.