Study of the Flow in a Dual Cavity Slot Die.

One-dimensional flow model for non-Newtonian fluids in a dual cavity slot die is presented. The viscosity of nonNewtonian fluids is treated as the Ellis model. The conservation equations of mass and momentum in a dual-cavity slot die are one-dimensionally simplified by assuming an appropriate mean flow over the cross section of the flow. The flow field in the slot is assumed to be fully developed. The equations of flow for the cavity and the slot are derived separately and then coupled. We use a finite difference method to solve these governing equations. Using this model, we find that the location and the cross-section area of a secondary cavity have large effects on the distribution of outlet flow. It is concluded that the dual cavity die can effectively reduce the flow non-uniformity.