Modelling of fibre orientation probability distribution in the jet-to-wire impingement

Abstract

Fibre orientation distribution is essential factor affecting the properties of produced paper. The fibre orientation distribution is mainly determined by the fluid dynamics in the wet-end and in the wire-section of the paper machine. In this work the fibre orientation probability distribution in the paper machine jet-to-wire impingement is studied using modelling. The model used in this work is based on diffusion-convection equation. In addition to the transport of the fibres due to the mean flow, the model includes flow induced rotation of the fibres and randomising turbulence effects. Thus, the purpose of the model is to estimate the effect of the flow dynamics on the development of the fibre orientation probability distribution.

Modeling and simulation of anisotropic cross-linked cellulose fiber networks with an out-of-plane topography

“…As mentioned in the introduction, the preferred fiber orientation is a complex function of jet, wire, and drainage speeds. Niskanen [17] showed that the orientation distribution of the fibers in the suspension can be approximated as an elliptic function of jet-wire speed difference and drainage speeds. In our simulations, we initially orient the suspended fibers with the same orientation distribution function.…”

“…Due to the speed difference between the jet and wire, hydrodynamic shear acts on the fibers in the MD. As a result, the commercially formed sheets manifest a preferential fiber orientation in the MD [17]. The fabric is a permeable surface with an associated weave pattern, designed to facilitate water drainage while retaining fibers, fines, fillers, and additives.…”