Analysis and Measurement of the Flocculation Intensity of Flowing Pulp Suspensions, 2001 Papermakers Conference Proceedings

Paper formation is strongly effected by the homogeneity of the pulp suspension in the approach system and in the headbox. It is generally believed that small scale, high intensity turbulence acts to deform and eventually rupture flocs and disperse fibers although there is some ambiguity in the literature. Improved experimental and analytic techniques are required to better understand the complex interactions between papermaking flow characteristics and the uniformity of pulp suspensions. To meet this need we have developed a technique to measure flocculation intensity in a developing turbulent pulp suspension flow, the Dynamic Panoramic View (DPV) system, and a pulp suspension velocity measurement technique based on Particle Image Velocimetry (PIV). To help understand these complex flows we use Large Eddy Simulation (LES) and Reynolds’ Averaged Navier Stokes (RANS) numerical techniques to simulate time varying turbulent flows and the flocculation variation in fiber suspensions respectively. The focus of this paper is a description of these techniques. The formation measurement and analytic techniques are applied to analyze a grid generated decaying turbulence flow field.