Modeling of Bubble Growth Dynamics and Nonisothermal Expansion in Starch-Based Foams During Extrusion

Authors

Lijun Wang, North Carolina Agricultural & Technical State UniversityFollow
Girish M. Ganjyal, University of Nebraska-LincolnFollow
David D. Jones, University of Nebraska-LincolnFollow
Curtis L. Weller, University of Nebraska-LincolnFollow
Milford Hanna, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2005

Comments

Published in Advances in Polymer Technology 24:1 (2005), pp. 29–45; doi: 10.1002/adv.20030 Copyright © 2005 Wiley Periodicals, Inc. Used by permission. http://www.interscience.wiley.com

Abstract

A mathematical model was developed to describe expansion phenomena in starch-based foams during extrusion. The model was divided into three parts to describe the microbubble growth dynamics, to couple bubble growth with extrudate expansion, and to describe the macrotransport phenomena in the extrudate, respectively. The differential equations involved in the model were solved by finite element schemes. For validating the model, the predicted radius, density, and residual moisture of final extrudate were compared with experimental data. Standard deviations between the predicted and experimental radius, density, and residual moisture of final extrudates were 16.7%, 11.2%, and 39.3%, respectively. The model was used to predict the profiles of downstream velocity, expansion ratio, moisture content, and temperature of extrudate during expansion.