Richard J. Udischas

Short and long term particle release from surfaces under the influence of gas flow

Preliminary measurement of particle reentrainment from 5 mm i.d. and 3 m long stainless steel tubes show two distinct regimes of concentration decay with time. In the short-term regime (t 1 being a function of flow rate and particle size. The ST regime appears to correspond to particle release by shear flow in the region where F = (adhesion force)/(removal force) ≲ 1. The long-term concentration decay is described by the desorption model of Wen and Kasper, where n(t) is proportional to (1t) exp (−tT). The LT regime appears to include the release of relatively strongly adhering particles where F > 1 up to about F = 5 or 6 (Wen and Kasper, 1989) which is classically forbidden and explained only in the model Reeks et al. (1988).