Simultaneous Phenomenon of Particle Deposition and Reentrainment: Effects of Surface Roughness on Deposition Layer of Striped Pattern

Formation of particle deposition layers on rough wall surfaces was studied as a simultaneous phenomenon of particle deposition and reentrainment. The test powders used were alumina of micron sizes and the experiments were conducted under turbulent aerosol flows. After particle deposition and reentrainment reached an equilibrium state, deposition layer of a striped pattern was formed. The striped pattern was characterized by the interval and the thickness, which decreased when the roughness of the wall surface increased. Further, the striped deposition layers moved slowly downstream, and the velocity of the moving deposition layers decreased with the increase of the surface roughness. A moment balance model was used to explain the effect of the surface roughness on the velocity of the moving deposition layers.