Tangential velocity measurements in a conical hydrocyclone operated with a fibre suspension
2007 (English)In: Minerals Engineering, ISSN 0892-6875, Vol. 20, no 4, 407-413 p.Article in journal (Refereed) Published
The tangential velocity flow field in a conical hydrocyclone was measured using a self-cleaning pitometer. The influence of pulp fibre concentration on the tangential velocity profile was of particular interest.
The measurement, showed that the pulp fibres had a strong influence on the tangential velocity profile. When operating the hydrocyclone with pure water, the velocity profile showed the typical combination of free-vortex-like rotation close to the hydrocyclone wall and solid-body-like rotation in the proximity of the hydrocyclone axis. This profile changed significantly when pulp fibres were added. At a low fibre concentration (1.2 g/l), the fibres smoothened the transition between the free-vortex-like and the solid-body-like region of the velocity profile. The location of the maximum tangential velocity moved to a larger radius. At higher fibre concentration (7.5 and 11 g/l), the free-vortex-like behaviour in the outer area was virtually suppressed. Due to networking, the fibre suspension in the entire hydrocyclone behaved as a solid body.
The radial acceleration profile and tangential rate-of-strain profile were determined. Based on these profiles, a hypothesis was proposed explaining the well-known observation that fractionation efficiency decreases significantly at higher fibre concentrations.
Place, publisher, year, edition, pages
2007. Vol. 20, no 4, 407-413 p.
hydrocyclones; shear forces
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-6376DOI: 10.1016/j.mineng.2006.09.008ISI: 000245938600013OAI: oai:DiVA.org:kth-6376DiVA: diva2:11070
QC 201007012006-11-222006-11-222010-08-04Bibliographically approved