FORMING OF PAPER SHEETS: A NUMERICAL SIMULATION BASED ON HYDRODYNAMICS OF FIBROUS SUSPENSIONS

摘要

A fiber-level simulation of paper forming in a twin-wire roll former is conducted with a furnish typical of fine paper. A mix of bleached kraft softwood and hardwood pulps was chosen, each refined to different levels. The resultant web structure obtained from the couch roll was determined from these numerical experiments. This wet web structure is used as input to a simulation of wet pressing, which produces a consolidated sheet structure. Results regarding how the change in fiber mix (e.g. HW/SW ratio) and changes in pulp refining affect the structure of the web are shown. Important features such as sheet fiber orientations, anisotropy, retention of fibers, fines and fillers and sheet exit moisture are all predicted by the simulation.