Parametric analysis and design of straight screw extruder for solids compaction

Screw extruders are commonly used in the food and polymer industries. Scientifically designed screw extruders for biomass compaction equipment are required to limit the existing problems faced in the industry. In this study, models based on the plug flow theory were developed and used to analyse the screw extruder for biomass compaction. The approach for development of the plug flow model involves a traction-and-retardation based mechanism utilizing force balances only, in contrast to the force and torque balance of previous models. The pressure developed along the length of the screw extruder was exponential and affected by the friction coefficients at biomass material interfaces between the screw and barrel, the channel depth and helix angle. The movement of material in the compaction region is drag-induced and the screw speed, channel depth and helix angle determine the flow rate through the screw channel. The approach utilized in this study for the development of models could be extended to study other types of screw extruders with relative ease compared to earlier approaches based on the plug flow theory.