Abstract: 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 [JP2]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.

Key words:

流场, 混合, 挤出机, 销钉机筒挤出机

摘要： 在一定简化条件下，对销钉机筒挤出机螺杆圆周展开面内的流场及分布混合效果以及销钉个数对流场和分布混合效果的影响进行了数值与实验研究.提出了流场中某点混合效果、整个流场平均混合效果以及混合效果统计分布的数值计算与评价方法.数值分析结果与实验结果具有较好的一致性.结果表明，销钉及螺棱切槽对物料具有明显的强化流动与混合的作用；6个销钉结构模型混合效果好于3个销钉结构模型，3个销钉结构模型好于有切槽无销钉结构模型，有切槽无销钉结构模型好于无切槽无销钉结构模型；有销钉结构较无销钉结构的平均混合效果提高30%～40%；有销钉结构随着时间的延长，混合效果不断提高，无销钉结构随着时间的延长，当混合效果达到一定值后则不再提高.

关键词:

流场, 混合, 挤出机, 销钉机筒挤出机