Validation of Flow Mechanisms of Fibre Suspensions in Small Diameter Pipes

摘要: Pipe friction loss data were obtained simultaneously for a eucalypt kraft suspension (2.0% pulp stock concentration) flowing in six tubes ranging diameter from 3.77 to 28.8 mm at velocities up about 3 m/s. This work is an extension of previous study using TMP and pine fibres only the three smallest tubes. It was confirmed lowest pipe diameters that water curves correspond but deviated markedly as tube increased. Extrusion-like flow into small produced either single axial-floc (long fibre pulps), or multiple end-on-end, longitudinally weaker, cylindrical flocs with shorter hardwood fibres. The elongated floc structures are more compliant near wall directionally aligned hence can readily retract deflect away shear rate increases.