A model to predict the pressure development in single screw extrusion

A general model for the prediction of the pressure field in single screw extrusion is developed. A special case of this model has already been established, where the channel depth was constant along the whole extruder length. Improvements to the previous model include corrections for non-constant channel depth in the screw. The channel depth geometry presented here is where the flights are attached to a core of conical shape. The one-dimensional model is developed in two parts: first a volume conservation equation is derived; this is then followed by the force balance acting on the system. The final equations are solved for pressure as a function of channel length. A model allowing the calculation of pressure drop in screws with a wider range of geometries is proposed.