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Thesis
Study of oscillating jets extruded from rectangular slots
Master of Science (M.S.), Drexel University
Feb 2001
DOI:
https://doi.org/10.17918/etd-9408
Abstract
Some important industrial extrusion processes involve extrusion of polymer melts from non-axisymmetric dies. The extrudate cross-section distorts, i.e. the shape of the cross-section of the extrudate differs from shape of the die due to die swell and surface tension. Surface tension force seeks to minimize the free surface are of the extrudate and thus distorts the cross-section of the extrudate towards a circle. The distortion in cross-section shape presents difficulties in the design of the dies. To investigate these distortions, vertical jets of liquids extruded from rectangular cross-section nozzles are studied. When a liquid jet exits from a rectangular nozzle, the jet cross-section just as it exits the nozzle is approximately elliptical. The jet exhibits oscillatory behavior i.e. the cross-section of the jet changes from elliptical shape to a circular and then again to elliptical shape. The various forces acting on the jet are surface tension, inertial, viscous and gravitational forces. The oscillations are primarily due to the surface tension force and inertial force. The viscous forces damp the amplitude of the oscillations and the gravitational force accelerates the axial velocity of the jet. It is seen from experiments that amplitude of oscillation of jet increases with increase in flowrate and /or decrease in viscosity. This thesis presents an experimental set-up to capture the shape of the oscillating jets and comparison between experimental results, analytical models and three dimensional finite element predictions of the free surface shape.
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Details
- Title
- Study of oscillating jets extruded from rectangular slots
- Creators
- Amitkumar Champalal Jain - DU
- Contributors
- Richard Allan Cairncross (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Chemical (and Biological) Engineering [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 9408; 991014632549704721