Multi-scale simulation of paperboard edge wicking using a fiber-resolving virtual paper model

Paper in proceeding, 2011

When liquid paperboard based package material is made aseptic, unsealed edges of the board are exposed to a liquid front which in some circumstances may soak the material to some extent. This is not desired since it may lead to aesthetic as well as functional defects. In order to make a priori predictions of the edge wicking properties of a given paper material, something which is of great interest to paperboard industry as well as packaging manufacturers, micro simulations are required. To calculate the penetration of fluid in the open edge of a paper sheet a multi-scale framework is developed. On the fiber micro-scale, virtual paper models are generated in PaperGeo [6]. In IBOFlow [7] a pore morphology method is used to calculate capillary pressure curves, and the active pores one-phase flow simulations are performed for relative permeabilities. The result is a database of capillary pressure curves and relative permeabilities as functions of saturation and porosity. The database is used as an input for a twophase flow simulation on a 2D virtual macro sheet to calculate the penetration of fluid in the paper. The multi-scale framework is validated against pressurized edge wick measurements with good agreement.