CFD modeling of a headbox with injecting dilution water in a central step diffusion tube

For engineering applications of water dilution controlling system, the fluid dynamics of a mixed flow was studied with computational fluid dynamics (CFD) simulations and self-designed experimental set-up. In order to examine the predictability of CFD model for the headbox in industrial scale, two pulp suspensions before mixing were treated as homogeneous flows separately. Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations. A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure-velocity coupling. Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube, and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.