Premium
Inertia and gravitational effects in extrusion dies for non‐Newtonian fluids
Author(s) -
Leonard William K.
Publication year - 1985
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760250910
Subject(s) - inertia , dimensionless quantity , die (integrated circuit) , mechanics , newtonian fluid , power law , materials science , flow (mathematics) , viscosity , non newtonian fluid , power law fluid , extrusion , classical mechanics , physics , composite material , mathematics , statistics , nanotechnology
Abstract An analysis is presented which allows the sheet or film die designer to estimate when inertial and gravitational effects are important. General theoretical equations are developed for end fed dies with arbitrary variation of the cavity cross sectional shape, cavity taper, slot length, and gap over the width. The method assumes viscous flow and a two dimensional approximation for the cavity flow. For fluid flow properties, it is assumed only that the apparent viscosity is a single valued function of the shear rate. In the important special case of constant die geometry and power law fluids, three dimensionless numbers plus the power law index are the parameters controlling the uniformity of flow from the die. Results are presented that illustrate when die orientations with respect to gravity and when fluid inertia are important. When they are not, simple expressions for die inlet pressure and uniformity index are given.