A NUMERICAL SOLUTION FOR SINGLE-SCREW EXTRUSION OF A POLYMER MELT

A general numerical‐analysis procedure is presented for the screw extrusion of a non‐Newtonian material. The full Navier‐Stokes energy and continuity equations are used in the numerical procedure. The flow is taken as steady and incompressible, and the viscosity is written according to the Ostwald‐de Waele model in which the viscosity is assumed to be inversely proportional to the square root of the second invariant of the rate of deformation tensor and exponentially dependent on the temperature. The procedure allows the prediction of vorticity, stream‐function, swirl velocity, internal energy, and viscosity over any cross section of a groove containing plastic. Calculations for the mass extrusion rate and power consumption (shear rate) for the screw extruder are also given. Typical cases are considered for which all the quantities listed above are determined. The results compare favorably with other theoretical work. Copyright © 1969 American Institute of Chemical Engineers