销钉机筒挤出机螺槽横截面内流体流动与混合的研究

Numerical and Experimental Analysis of Flow and Distributive Mixing in Cross Section of Screw Channel in Pin Barrel Extruder

在一定简化条件下,对销钉机筒挤出机螺槽横截面内的流场及混合均化效果以及销钉位置对流场和混合均化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均化效果、整个流场平均混合均化效果以及混合均化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,销钉对物料具有明显的强化流动与混合均化的作用;销钉愈接近于螺棱, 强化混合均化的效果愈显著;有销钉结构较无销钉结构的平均混合均化效果提高2.5%～5.6%;有销钉结构随着挤出时间的增加,混合均化效果不断提高,无销钉结构随着挤出时间的增加,当混合均化效果达到一定值后则不再提高。

Based on the reasonable simplified model of the pin barrel extruder, numerical and experimental analyses were carried out to investigate the flow field and mixing effect in the cross section of the screw channel, meanwhile the influence of pin on flow and mixing effect was also discussed. A method of numerical analysis and evaluation the mixing effect of certain point, the average mixing effect and the statistical distribution of the mixing effect in the whole fluid field is put forward. The numerical results are in good agreement with the experimental results. By the studies, following conclusions were obtained. First, the introduction of pins can greatly improve the mixing effect. Second, the closer distance between pin and screw flight results in better mixing effect. Third, compared with the cross section of the screw channel without pin, the average mixing effect in the cross section of the screw channel containing pin is increased by 2.5%~5.6%. Fourth, the mixing effect in the cross section containing pin is continuously increased with time, but the mixing effect in the cross section without pin cant be increased with time when the mixing effect reaches a certain value.