Modeling Flow in Cylindrical Extruder Dies

Volumetric flowrate was studied in the die of a single screw extruder. Variables included the ratio of die length to die diameter, barrel to die diameter, barrel and die temperature, screw speed and product moisture. Die conductance was determined graphically and analytically. Results indicated that for a constant pressure drop across the die, increasing temperature, die diameter or moisture increased flowrate. Dimensional analysis was used to study the effect of each parameter on the flow through the extruder die. An expression for temperature rise due to viscous dissipation for isothermal flow in the die was developed and nomographs are presented.