COMPUTER-SIMULATION OF STARCHY PRODUCTS TRANSFORMATION BY TWIN-SCREW EXTRUSION

A computer program based on a comprehensive model of corotating twin-screw extrusion has been developed Apart from the specific study of each section of the extruder, it allows a wide range of simulations of the complete process for starchy products. Mixing performances of kneading elements were computed Axial profiles of filling ratio, temperature, pressure and specific shear energy (computed specific energy - CSE) were predicted, and good agreement was found with experimental results and other theoretical studies where available. The program was validated for many different extrusion conditions on the basis of the comparison between computed and measured pressure and apparent viscosity at the die, specific mechanical energy and CSE. The value of CSE in predicting the transformation of starchy products is emphasized and an example of the use of computer simulation for process scale-up is given.