Abstract." A five zone mathematical model of a plasticating extruder is presented. Its application in the design of new and improvement of existing extruders is briefly described. The model is based on theories proposed by Darnell and Mol, Tadmor, Broyer, McKelvey, Klein, Schneider, Fenner, Poon and Jankov. A comparison between experiments and theoretical calculations is included.

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A b s t r a c t :The results of a numerical study (using finite differences) of heat transfer in polymer melt flow is presented. The rheological behaviour of the melt is described by a temperature-dependent power-law model. The curved tube wall is assumed to be at constant temperature. Convective and viscous dissipation terms are included in the energy equation. Velocity, temperature and viscosity profiles, Nusselt numbers, bulk temperatures, etc. are presented for a variety of flow conditions. I n t r o d u c t i o nPolymer melt flow in curved tubes occurs in practically all e q u i p m e n t used for m a n u f a c t u r i n g and processing plastics. In the p r o d u c t i o n of m a n -m a d e fibre the p o l y m e r melt flow via a m a n i f o l d is a typical example of such a flow. In the manifold, the melt is distributed from one input stream to 2 4 -4 8 output streams and each output stream is r e q u i r e d to have the same properties (temperature, viscosity, pressure, melt index, etc.).Previously published models o f fluid flow in curved tubes have been derived using the assumption o f isothermal l a m i n a r and N e w t o n i a n flow. A s u m m a r y of such models, up to 1978, is given by Baurmeister and Brauer [1]. O t h e r theoretical investigations o f the flow in curved pipes of different cross-section (circle, square, triangle, etc.) [2][3][4][5][6][7][8][9][10][11] are also only applicable for N e wtonian fluids.

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