Numerical Simulation Of Twin-screw Extrusion Of Starch Based Material

Extrusion technology is widely applied in various processing (e.g. plastics, foods, pharmaceutical, rubber, and other high viscous materials) because this process combines heating, shearing, mixing and shaping in one unit operation. In food industries, twin-screw extrusion processing has played important role to fulfill the market demand of convenient food products (e.g. ready-to-eat puffed cereals and low density, expanded snack food). Therefore, understanding of twin-screw extrusion is essential for further food products development. The design and optimization of the extrusion processing has been going by trial and error experimental method, which is time consuming and requires great efforts. Moreover this method does not provide insight information of the material flow history and the mixing mechanism that is useful for the extruder design and scale up. An alternative method through numerical simulation supported by the rapid development of computer technology provides the insight information (i.e. flow field, pressure field and the mixing mechanism) of the twin-screw extrusion, which has been done in this study.