Simulation of Water Removal in Paper Based on a 2D Level-Set Model Coupled with Volume Forces Representing Fluid Resistance in 3D Fiber Distribution

A numerical model of a vacuum dewatering process was established with a level-set method to simulate two-phase flow in a two-dimensional paper sheet model with constructed volume forces representing flow resistance in a three-dimensional environment. Nine cases of various volume force representations were investigated by comparing numerical and experimental data. Based on the dry content and dwell time relation, the best model is obtained when accounting for in-plane flow resistance at the paper-wire interface. Compared to the other numerical cases, considering the blockage of the pore space, the top layer of the wire plays an essential role in determining the flow resistance during the vacuum process. To validate the maximum dewatering rate obtained in the model, new experimental data with a higher frequency of sampling are needed.The computational time for the two-phase flow models in this study is extensively reduced due to the removal of the internal structure. This distinction enables time-efficient simulations of the vacuum dewatering process in which several dewatering parameters such as the level of the vacuum, the influence of a moving vacuum pulse, and higher basis weights could be investigated.