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ISSN Online: 2377-424X

ISBN Print: 1-56032-797-9

International Heat Transfer Conference 11
August, 23-28, 1998, Kyongju, Korea

A NUMERICAL INVESTIGATION OF NON-ISOTHERMAL EXTRUSION THROUGH ANNULAR DIES - INFLUENCE OF WALL TEMPERATURES ON EXTRUDATE SWELL

Get access (open in a dialog) DOI: 10.1615/IHTC11.50
pages 27-32

摘要

The influence of die wall temperatures on the extrudate's swelling behaviour is investigated numerically when viscous fluids of a Newtonian type are extruded through annular dies.
It is found that cooling the die walls enhances extrudate's thickness swell while heating them produces the opposite effects, suppressing swelling to the point of contraction in some cases. Furthermore, imposing different temperatures on the two annular walls can result in the extrudate swinging substantially inward (radius of both walls decreased) or outward (radius of both walls increased), the movement being in the direction of the cooler wall. All this is in addition to the enhancing influence of the higher Nahme-Griffith number and narrower annular gap (or lower Peclet number) on the extrudate's thickness swell that has been reported earlier. These patterns of behaviour can also be seen to be consistent with an extrapolated interpretation of a previous theory.
The implication is that it now seems possible for the extrudate to be manipulated to expand or contract in thickness, its walls caused to move outward or inward relative to those of the die orifice, by simply imposing appropriate temperatures on the die walls. This would have significant consequence on the control of the extrusion process for correct dimensions of the extrudate, and the design of dies.