Abstract
In analytical analyses for single-screw extruders the simplified approach of rotating the barrel and keeping the screw fixed is often used instead of rotating the screw and fixing the barrel. Although the flow field is independent of the reference frame, as has already been shown to a satisfactory degree (Rauwendaal et al., 1997), the question of the dependence of the melt temperature rise on the reference frame is still being challenged, e.g. Campbell et al. (2001, 2008). In this work we develop a finite-volume CFD code allowing for the three-dimensional simulation of the flow and temperature rise in both reference frames. The question of frame invariance is addressed by simulating the flow of a Newtonian-like polycarbonate both in a two-dimensional cross-section of a single-screw extruder and in a three-dimensional model with two full turns of the screw. Our results show that the kinematics and the melt temperature rise are equal for screw- and barrel-rotation and thus independent of the reference frame. Furthermore, the presence of a clearance flow has a negligible influence on the temperature rise.
References
Berry, G. C., Fox, T. G., “The Viscosity of Polymers and their Concentrated Solutions”, Adv. Polymer Sci., 5, 261–357 (1968) 10.1007/BFb0050985Search in Google Scholar
Campbell, G. A., Cheng, H., Wang, C., Bullwinkel, M. and te-Riele, M. A., “Temperature Rise in Single Screw Pump-extruders”, SPE ANTEC Tech. Papers, 47, 152–156 (2001)Search in Google Scholar
Campbell, G. A., Spalding, M. A. and Carlson, F., “Prediction of Melt Temperature Rise in Single-screw Pump Extruders”, SPE ANTEC Tech. Papers, 54, 267–271 (2008)Search in Google Scholar
Campbell, G. A., Sweeney, P. A., Dontula, N. and WangC.H., “Frame Indifferences: Fluid Flow in Single Pumps and Extruders”, Int. Polym. Proc., 11, 199–207 (1996)Search in Google Scholar
Campbell, G. A., Sweeney, P. A. and Felton, J. N., “Experimental Investigation of the Drag Flow Assumption in Extruder Analysis”, SPE ANTEC Tech. Papers, 37, 219–223 (1991)Search in Google Scholar
Carley, J. F., Mallouk, R. S. and McKelvey, J. M., “Simplified Flow Theory for Screw Extruders”, Ind. Eng. Chem., 45, 974–978 (1953) 10.1021/ie50521a032Search in Google Scholar
Holzapfel, G. A.: Nonlinear Solid Mechanics: A Continuum Approach for Engineering, 1st Edition, Wiley, New York (2000)Search in Google Scholar
Jasak, J., Weller, H. G. and Gosman, A. D., “High Resolution NVD Differencing Scheme for Arbitrarily Unstructured Meshes”, Int. J. Numer. Meth. Fluids, 31, 431–449 (1999) 10.1002/(SICI)1097-0363(19990930)31:2<431::AID-FLD884>3.0.CO;2-TSearch in Google Scholar
Mohr, W. D., Saxton, R. L. and Jepson, C. H., “Mixing in Laminar-flow Systems”, Ind. Eng. Chem., 49, 1855–1856 (1957) 10.1021/ie50575a030Search in Google Scholar
Rauwendaal, C., Osswald, T. A., Tellez, G. and Gramann, P. J., “Flow Analysis in Screw extruders – Effect of Kinematic Conditions”, Int. Polym. Proc., 8, 327–333 (1998)Search in Google Scholar
Spalding, M. A., Dooley, J., Hyun, K. S. and Strand, S. R., “Three Dimensional Analysis of the Metering Section of a Single-screw Extruder”, SPE ANTEC Tech. Papers, 39, 1533–1541 (1993)Search in Google Scholar
© 2013, Carl Hanser Verlag, Munich
