Modelling the effect of shear flow on fibre orientation anisotropy in a planar contraction

Författare: Hyensjö, null, Dahlkild, A. A., Krochak, P, Olson, J, Hämäläinen, J.P.
Dokumenttyp: Artikel
Tillstånd: Publicerad
Tidskrift: Nordic Pulp and paper research Journal
Volym: Vol. 22, No.3   376-382
År: 2007


The effect of turbulence generating vanes and its location in a planar contraction on fibre orientation anisotropy was studied by mathematical modelling. We use single phase CFD modelling as an input for the fibre orientation dispersion model to study the effect of shear flow and turbulence in an accelerated fluid flow on fibre orientation anisotropy. For different streamlines in the contracting channel, the fibre orientation distribution model is solved, and the fibre orientation anisotropy could be studied along streamlines near the vane wall and vane tip and further away downstream. The boundary layer did decrease the fibre orientation anisotropy both in the plane of paper and in the plane of contraction, i.e the fibres were less oriented. For the outlet profile of the contraction the fibre orientation anisotropy was more effected by the blunt vane tip than the tapered one. Experimental results in the literature were used to validate this modelling approach and a good qualitative agreement was achieved.