Engineering
Evaluating Non-Newtonian Fluid Behavior in a Twin-Screw Extruder
Quick fact
Many polymer melts and food doughs are shear-thinning, meaning their viscosity can drop by a factor of 10 or more as the screw speed—and thus the shear rate—increases. This dramatically alters the pressure buildup and flow uniformity inside a twin-screw extruder.
Why this is interesting
Ever wonder why the dough coming out of a pasta maker changes consistency as it moves through, even though the same ingredients are used? The same thing happens – on a much bigger scale – inside a twin-screw extruder, where the fluid's behavior is anything but simple.