Stochastic analysis of a collection process of submicron particles on a single fiber accounting for the changes in flow field due to particle collection

摘要

Flow effects on the collection of submicron particles by a single fiber are investigated by stochastic analysis of the particle deposition evolution. The incident particle-laden stream is simulated by a Lagrangian-Eulerian approach, while the flows around a fiber and particles accumulation are solved using the Lattice Boltzmann method in conjunction with Brownian dynamics to trace the trajectory of randomly moving particles. A boundary surface on the fiber also evolves to include the changing morphology due to particle deposition. The simulation method is validated for collection efficiencies and pressure drop of clean fiber. Brownian effects on particle accumulation were examined in terms of the Peclet number. Predictions of evolving particle-layered filter geometry showed a strong effect of carrier-gas convection on the extent and the morphology of the particle accumulation, which, in turn affected the morphology of the filter. This strong interaction between the carrier-gas convection and the filter membrane causes more active particle accumulation, and thus at all Peclet numbers examined with carrier-gas convection yielded higher collection efficiencies, but with a higher pressure drop.