A novel device to measure pulp fiber hydrodynamics.

Application: This paper describes a new device for measuring the hydrodynamics of pulp fibers. The device may be used to predict the fiber separation that occurs in hydrocyclones, given a knowledge of the flow field in the hydrocyclone.

In order to understand the separation of different pulp fibers in a hydrocyclone, there is a need to study the hydrodynamics of pulp fibers. A novel device, called the rotating tank hydrodynamometer (RTH), has been developed to study the hydrodynamics of pulp fibers under conditions similar to those in hydrocyclones. The RTH is capable of achieving a wide range of Reynolds numbers (up to about 0.5 based on fiber diameter) with water: Use of the tank as a measuring device has been validated by testing glass spheres, copper wires, and nylon fibers, which all have known hydrodynamic characteristics. The RTH has also been used to test hardwood kraft pulp fibers. Long wood fibers travel taster than shorter fibers under identical hydrodynamic conditions. At the high centripetal accelerations present in a hydrocyclone (700m/[S.sup.2]), the mean "radial settling velocity" of fibers is about 7mm/s.

Wong and Green are with the Department of Mechanical Engineering, University of British Columbia 2324 Main Mall, Vancouver, BC, V6T 1Z4, Canada. Email Green at [e-mail]