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The coupled 3-D Simulation of Flow and Heat Transfer In the Extruder and the Die. M. Malik and D. Kalyon Stevens Institute of Technology 12 th JOCG Continuous Mixer and Extruder Users Group Meeting Indian Head, MD October 31, 2002. Impetus for the new approach.
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The coupled 3-D Simulation of Flow and Heat Transfer In the Extruder and the Die M. Malik and D. Kalyon Stevens Institute of Technology 12th JOCG Continuous Mixer and Extruder Users Group Meeting Indian Head, MD October 31, 2002
Impetus for the new approach • The traditional technique for mathematical modeling separates different regions in the extruder and carries out the solution in a divorced fashion. • Our new approaches marry the different regions in the extruder and allows more accurate solutions to be developed.
Outline • Review the traditional methodology with some typical results for extruder elements and dies • Illustrate the new technique on single screw and then in twin screw extrusion process.
Yield stress=20165Pa n=0.4; m=30160 Pa-sn
Viscoplastic fluids a) for analytical solutions b) for numerical solutions, 2-D and 3-D FEM, Papanastasiou Eq’n:
Traditional FEM method for simulation of processing flows • Treat the die and the extruder separately • Treat the different sets of screw elements separately
1-D or 2-d analysis n t Navier’s slip condition Unit normal vector Unit tangent vector Total stress tensor
=(T-To)/(Tb-To) Tb (Barrel Temperature) ; To (Entrance Temperature) 1. at z=0 (Entrance) =0 2. On the barrel surface =1 3. On the screw surface
Conservation of linear momentum upon application of Bubnov Galerkin: Weighting function Total stress tensor Unit tangent vector Unit normal vector Wall slip Navier’s slip coefficient No material exchange
Streamline Upwind Petrov-Galerkin Method (SUPG) Hughes et al., 86
Simulation of particle path lines in the slit die Non-diffusive tracers
Continuous Processing Lab of HfMI: Twin Screw ExtruderFacilityand theSlit Die Rheometer
Conclusions • New methodologies are developed to allow for the simulation of multiple elements of the extruder simulataneously • The new method will significantly enhance our simulation capability.
Acknowledgement • We acknowledge with gratitude the support of TACOM/ARDEC, NSWC/IH, BMDO/IST (ONR), DARPA, PBMA and various companies including Unilever, Duracell, Henkel-Loctite, GPU, and MPR which made this investigation possible.