A Simulation of the Effects of Formula Variations on the Transient Output of Single Screw Food Extruders

Abstract A simulation of the transient response of single screw extruders to fluctuations in formula of the extrudate is described. Any changes in extrudate composition, which result in changes in the viscous properties of the extrudate, result in transient behavior in the output of an extruder. Using existing extruder models, a simulation was used to study the transient behavior of an extruder in response to compositional variations in the extrudate. The results of the simulation suggest that for small variations in the composition of the material being extruded, large transient responses in extruder output will be observed. Depending on the relationship between the composition and viscosity of the extrudate, the change in output of the extruder can vary between insignificance and virtual stoppage of flow. The implications of these extruder transients on the design and operation of extrusion systems are discussed.