Study On The Dispersive Mixing Performance Of The Reciprocating Single Screw PIN-Barrel Extruder

The purpose of this paper was to study the mixing performance of the reciprocating single screw pin-barrel extruder. In this paper, the differences of the mixing performance between the reciprocating single screw pin-barrel extruder and the twin screw extruder were studied through the experimental results of the carbon black/PP system and the characteristics of the flow field which were got by the finite element numerical simulation. And on this basis, the factors that influenced the mixing performance of the reciprocating single screw pin-barrel extruder were studied by the finite element numerical simulation, which provided a theoretical basis for the optimization of the mixing performance of the reciprocating single screw pin-barrel extruder. In the end, we found that the screw configuration was influenced by the transmission mechanism of the drive system, which could make different mixing performances.1. Comparative study on mixing performance between the reciprocating single screw pin-barrel extruder and the twin screw extruder. The variations of dispersive mixing performances of the reciprocating single screw pin-barrel extruder and the twin screw extruder as the screw speed, the feed rate and the barrel temperature were studied by the electrical conductivity of the carbon black/PP. The reason of the differences between the two extruders was analyzed by the electron microscopy images of carbon black/PP and the result of the numerical calculation.2. Influences of process parameters and geometrical parameters on the mixing performance of the reciprocating single screw pin-barrel extruder. The distributive characteristics of the fluid in the reciprocating single screw pin-barrel extruder were studied by a two-dimensional model with periodic boundary. The influences of the screw speed and the feed rate on the mixing performance of the reciprocating single screw pin-barrel extruder were analyzed by the finite element numerical simulation. The reciprocating motion parameters and the pin characteristic parameters could affect the geometric configurations of the mixing element, so that the mixing performances of the reciprocating single screw pin-barrel extruder were different.3. Design of the new mixing elements. Based on the influence of the geometric parameters on the mixing performance, a new mixing element was design considering the reciprocating rotation frequency ratio and the rows of the pins. The new mixing element had12rows of pins in the barrel and the reciprocating rotation frequency ratio was3. The differences of the mixing performance between the new element and the traditional mixing element were compared in this paper.4. Relationship between the drive mechanism of reciprocating motion and the mixing performance. The transmission mechanisms and the motion of different drive systems were different, so that the configurations of the mixing elements were each different. The mixing elements were designed according to the transmission mechanisms, the shear stress distribution, the time residence time, the final carbon black particle size and the mixing performance of different mixing elements were analyzed through the finite element numerical simulation.The study of this paper could provide theoretical guidance and technical support for the development of the reciprocating single screw pin-barrel extruder.