OJFD  Vol.4 No.1 , March 2014
3D Thermo-Fluid Dynamic Simulations of High-Speed-Extruded Starch Based Products
Abstract: This paper aims to investigate a method to perform non-isothermal flow simulations in a complex geometry for generalised Newtonian fluids. For this purpose, 3D numerical simulations of starch based products are performed. The geometry of a co-rotating twin-screw extruder is considered. Process conditions concern high rotational speed (up to 1800 rpm), different flow rates (30, 40 and 60 kg/h) and water contents (22% and 36%), for a total of 54 simulations. To cope with the geometry complexity a Mesh Superposition Technique (MST) was adopted. The pseudoplastic behaviour of the fluid is taken into account by considering viscosity as function of shear rate (Ostwaldde Waele relationship) and temperature (Arrhenius law). Simulated temperature variations are compared with measurements at same process conditions for validation. Qualitative behaviour of temperature T and shear stress  along the screw are analysed and comparisons of different process conditions are presented. By these simulations a database is formed to develop a process control strategy for novel extruder operating points in food technology.
Cite this paper: Cubeddu, A. , Rauh, C. and Delgado, A. (2014) 3D Thermo-Fluid Dynamic Simulations of High-Speed-Extruded Starch Based Products. Open Journal of Fluid Dynamics, 4, 103-114. doi: 10.4236/ojfd.2014.41008.

[1]   Senouci, A. and Smith, A.C. (1988) An Experimental Study of Food Melt Rheology. I. Shear Viscosity Using a Slit Die Viscometer and Capillary Rheometer. Acta Rheologica, 27, 546-554.

[2]   Xie, F., Yu, L., Su, B., Liu, P., Wang, J. and Chen, L. (2009) Rheological Properties of Starches with Different Amylose/ Amylopectin Ratios. Journal of Cereal Science, 49, 371-377.

[3]   Chang, Y.K., Martinez-Bustos, F., Park, T.S. and Kokini, J.L. (1999) The Influence of Specific Mechanical Energy on Cornmeal Viscosity Measured by an On-Line System during Twin-Screw Extrusion. Brazilian Journal of Chemical Engineering, 3, 285-295.

[4]   Willet, J.L., Millard, M.M. and Jasberg, B.K. (1997) Extrusion of Waxy Maize Starch: Melt Rheology and Molecular Weight Degradation of Amylopectin. Polymer, 38, 5983-5989.

[5]   Della Valle, G., Boché, Y., Colonna, P. and Vergnes, B. (1995) The Extrusion Behaviour of Potato Starch. Carbohydrate Polymers, 28, 255-264.

[6]   Della Valle, G., Vergnes, B., Colonna, P. and Patria, A. (1997) Relations between Rheological Properties of Molten Starches and their Expansion Behaviour in Extrusion. Journal of Food Engineering, 31, 277-296.

[7]   Launay, B. and Lisch, J.M. (1983) Twin-Screw Extrusion Cooking of Starches: Flow Behaviour of Starch Pastes, Expansion and Mechanical Properties of Extrudates. Journal of Food Engineering, 2, 259-280.

[8]   Xie, F., Halley, P.J. and Avérous, L. (2012) Rheology to Understand and Optimize Processibility, Structures and Prop- erties of Starch Polymeric Materials. Progress in Polymer Science, 37, 595-623.

[9]   Janssen, L.P.B.M., Moscicki, L. and Mitrus, M. (2002) Energy Aspects in Food Extrusion-Coocking. International Agrophysics, 16, 191-195.

[10]   Liang, M., Huff, H.E. and Hsieh, F.H. (2001) Evaluating Energy Consumption and Efficiency of a Twin-Screw Extruder. Journal of Food Science, 67, 1803-1807.

[11]   Shi, C., Wang, L., Wu, M., Adhikari, B. and Li, L. (2011) Optimization of Twin-Screw Extrusion Process to Produce Okara-Maize Snack Foods Using Response Surface Methodology. Journal of Food Engineering, 7, 1-24.

[12]   Guha, M., Ali, S.Z. and Bhattacharya, S. (1997) Twin-Screw Extrusion of Rice Flour without a Die: Effect of Barrel Temperature and Screw Speed on Extrusion and Extrudate Characteristics. Journal of Food Engineering, 32, 251-267.

[13]   Hubner, G.R. (2000) Twin-Screw Extruders. In Riaz, M.N., Ed., Extruders in Food Applications, CRC Press, Taylor & Francis Group, Boca Raton, 8-114.

[14]   Della Valle, G., Barrès, C., Plewa, J., Tayeb, J. and Vergnes, B. (1993) Computer Simulation of Starchy Products’ Transformation by Twin-Screw Extrusion. Journal of Food Engineering, 19, 1-31.

[15]   Ishikawa, T., Kihara, S.I. and Funatsu, K. (2000) 3-D Numerical Simulations of Nonisothermal Flow in Co-Rotating Twin Screw Extruders. Polymer Engineering and Science, 40, 357-364.

[16]   Avalosse, T., Rubin, Y. and Fondin, L. (2002) Non-Isothermal Modeling of Co-Rotating and Contra-Rotating Twin Screw Extruders. Journal of Reinforced Plastics and Composites, 21, 419-429.

[17]   Gupta, M. (2008) Non-Isothermal Simulation of the Flow in Co-Rotating and Counter-Roteting Twin-Screw Extruders using Mesh Partitioning Technique. In: ANTEC 2008 Plastics: Annual Technical Conference Proceedings, ANTEC, Milwaukee, 316-320.

[18]   Emin, M.A. and Schuchmann, H.P. (2013) Analysis of the Dispersive Mixing Efficiency in a Twin-Screw Extrusion Processing of Starch Based Matrix. Journal of Food Engineering, 115, 132-143.

[19]   Bravo, V.L., Hrymak, A.N. and Wright, J.D. (2000) Numerical Simulation of Pressure and Velocity Profiles in Kneading Elements of a Co-Rotating Twin Screw Extruder. Polymer Engineering and Science, 40, 525-541.

[20]   (2009) Ansys Polyflow 12.1 User’s Guide.

[21]   Yacu, W.A. (1985) Modeling of a Twin Screw Co-Rotating Extruder. Journal of Food Engineering, 8, 1-21.

[22]   Sakiyama, T., Han, S., Kincal, N.S. and Yano, T. (1993) Intrinsic Thermal Conductivity of Starch: A Model-Independent Determination. Journal of Food Science, 58, 413-415.

[23]   Noel, R.T. and Ring, S.G. (1992) A Study of the Heat Capacity of Starch/Water Mixtures. Carbohydrate Research, 227, 203-213.

[24]   Liu, J.W.H. (1992) The Multifrontal Method for Sparse Matrix Solution: Theory and Practice. Society for Industrial and Applied Mathematics, 34, 82-109.

[25]   Rauwendaal, C. (2001) Polymer Extrusion. Carl Hanser Verlag, Munich.