Abstract
The flow characteristics of wood pulp suspensions in circular pipes have been investigated experimentally. The disruptive and turbulent shear stresses on the pipe wall are formulated as a function of the fiber concentration. The yield shear stress becomes large with increasing pulp fiber concentration. The flocculation of pulp fibers starts to become loose near the pipe wall when a shear stress exceeding about four times the yield shear stress acts on the suspension. Furthermore, the pulp fibers become to disperse uniformly over the cross section owing to the shear stress at least approximately ten times the yield shear stress.
