Modeling the secondary cavity of two-cavity dies

Abstract

Dies having two distribution cavities and slots are sometimes used in film-forming applications demanding high uniformity. The flow distribution accomplished by the primary cavity and slot is improved by the secondary cavity and slot. In the primary cavity, the main flow direction is lengthwise, and the flow resembles that in a duct. On the other hand, the main flow direction in the secondary cavity is in the plane of the cross section. Nonetheless, in previous literature, the same flow equation is used for both cavities. The principal result of this work is a flow equation for the secondary cavity that takes account of the underlying cross flow. Applying this equation shows that both inertia and pseudoplasticity adversely affect the performance of a secondary cavity and slot.