NUMERICAL AND EXPERIMENTAL ANALYSIS OF FLOW AND DISTRIBUTIVE MIXING IN UNFOLDED SURFACE OF SCREW IN PIN BARREL EXTRUDER

Based on the reasonable simplified model of the pin barrel extruder, numerical and experimental analyses were carried out to investigate the flow field and distributive mixing effect on the unfolded surface of the screw.Meanwhile the influence of pins on flow and mixing effect was also discussed A method of numerical analysis and evaluation of the mixing effect at a certain point, the average mixing effect and the statistical distribution of the mixing effect in the whole fluid field was developed The numerical results were in good agreement with the experimental results From the studies,the following conclusions are obtained First, the introduction of pins and slices into the screw flights can greatly improve the flow and mixing effect.Second, the unfolded surface of the screw with six pins has better mixing ability than the surface with three pins,The surface with three pins has better mixing ability than the surface with slices and without pins.The surface with slices and without pins has better mixing ability than the surface without slices and pins.Third,compared with the unfolded surface of the screw without slices and pins, the average mixing effect on the unfolded surface of the screw containing pins is increased by 30%-40%.Fourth, the mixing effect on the unfolded surface containing pins is continuously increased with time, but the mixing effect on the unfolded surface without pins can not be increased with time when the mixing effect reaches a certain value