| Accurate and effective quality control of the manufacture of information grade paper is becoming the primary papermaking concern with the recent and upcoming advances in modern printing technology. An important quality issue, but poorly understood phenomenon, is the interactions between papermaking flow characteristics and the uniformity of fibrous suspensions. To extend knowledge and understanding of these complex interactions, the behavior of a flowing pulp suspension in a grid generated turbulence flow field was experimentally studied and the scale dependency of the suspension uniformity was modeled. A Dynamic Panoramic View technique was developed simultaneously to measure and quantify the suspension local mass variability along the stream-wise direction as well as the transverse direction. The effects of mean flow velocity, concentration, and local flow characteristics on the local mass variability of a representative hardwood kraft pulp were studied. A model was developed to characterize the rate of fibre aggregation in a decaying turbulent flow field. This model was found to be in excellent agreement with experimental data. |
