OVERVIEW OF PARTICLE RESUSPENSION PROVESSES iNDOOR AIR POLLUTION

An overview of particle removal and re-entrainment under various conditions is presented. A detailed analysis of particle resuspensions in turbulent flow is also performed. The instantaneous fluid velocity field is generated by the direct numerical simulation (DNS) of the Navier-Stokes equation via a pseudospectral method. Particle removal mechanisms in turbulent channel flows are examined and the effects of hydrodynamic forces, torques and the near-wall coherent vorticity are discussed. The particle resuspension rates are evaluated, and the results are compared with the model of Reeks. The particle equation of motion used includes the hydrodynamic, the Brownian, the shear-induced lift and the gravitational forces. An ensemble of particles is used for particle resuspension and the subsequent trajectory analyses. It is found that turbulent near wall vortical structures play an important role on small particle resuspension. Environmental importance of particle resuspension in connection to air pollution in indoor environment is described. It is shown that personal exposure to indoor pollution is orders of magnitude larger than those to outdoor environment.