Finite Element Modeling of Fluid Flow, Heat Transfer, and Melting of Biomaterials in a Single-screw Extruder

ABSTRACT: A mathematical model was developed to simulate non-isothermal plug flow of granular starch in feed zone, melting in transition zone, and non-Newtonian melt flow in metering zone and die channel during single-screw extrusion processing. The maximum deviations between the predicted and experimental pressure at the die entrance, product temperature at the die entrance, and minimum residence time were about 20%, 2.5%, and 8%, respectively, of the measured values when the barrel temperatures were 50°C in the feed zone and 120°C in the rest zones. The deviations were within 40%, 4%, and 15%, respectively, of the measured values when the barrel temperatures were 50°C in the feed zone and 140°C in the rest zones. Simulations were carried out to investigate the operating characteristics of an extruder, the melting degree, and profiles of pressure and bulk temperature during extrusion.