Computational Investigation of the Flow Through a Headbox, 2001 Engineering Finishing & Converting Conference Proceedings

M. Reza Shariati, E. Bibeau, X. Zhang, M. Salcudean, I. Gartshore, Z. Abdullah--The fluid flow through the headbox has a significant effect on the resulting paper quality. The exit flow is influenced to a great extent by the incoming flow into the converging section and therefore it is important to develop powerful computational tools, which are able to compute through the header, tubes and convergent section. Mean flow and turbulence characteristics have been computed through the header, tubes and slice of a generic headbox geometry. From the results, it is clear that the flow non-uniformities originating in the header can be more significant than those coming from the individual diffuser tubes. The variation of the turbulence intensity through the slice is explored and the influence of flow through the tubes on turbulence intensity is assessed. The influence of the convergent section on fiber orientation is explored by using a fiber model, which tracks the fiber motion. Comparisons are made between numerical predictions and the observed statistics of fiber orientation in a model headbox. The results emphasize the importance of turbulent dispersion as far as fiber orientation is concerned, but show that the present simulation correctly represents trends of fiber orientation in the convergent section.