Analysis Of Conveying And Mixing Mechanism Of Conical Twin Screw Extruder Based On Discrete Element Method

The conical twin-screw extruder is a widely used type of screw extruder.It is mainly used for extrusion molding and mixing and granulation in the polymer production and processing industry.At present,the conical twin-screw extruder is one of the important models in the polymer processing industry because of its unique structure and high-efficiency extrusion capacity.In recent years,with the rapid development of polymer processing technology,domestic and foreign researches on the mixing of the conical twin-screw extruder in the melting section are relatively extensive,while the research on the solid conveying section is relatively small.This article mainly focuses on the conical twin-screw extruder.The conveying and mixing efficiency of the solid conveying section of the screw extruder is studied,and the importance of the solid conveying section to the material extrusion process is analyzed.To a certain extent,it makes up for the lack of research in the solid conveying section of the conical twin-screw extruder.The development of the solid conveying section of the shaped twin-screw extruder has important practical significance.This paper establishes the model through the 3D modeling software Solid Works,and uses the discrete element method to simulate and analyze the HDPE solid particles in the solid conveying section of the conical twin-screw extruder.The main research contents are as follows:(1)First,through EDEM to simulate the pellet extrusion process in the conical twin-screw extruder,obtain the speed cloud diagram in the extruder and analyze the speed distribution law,and at the same time carry out different areas in the same lead of the conical twin-screw extruder.The force analysis shows that the particles receive the greatest force in the screw meshing zone,and the screw speed and particle size will affect the force of the particles,which provides a certain reference for the selection of the speed and particle size during the extrusion process of the conical twin-screw extruder..(2)The solid conveying section of the extruder is mainly used for material conveying.In this paper,by simulating the HDPE particle conveying process,research is carried out in terms of the structure and particle parameters of the extruder.The extruder mainly studies the screw speed,the width of the screw,and the screw.Comparing the conveying output between groove depth and screw radius ratio,lead,and lead gradual change,the particle radius,particle shape,friction coefficient and restoring coefficient of the particle and the extruder are compared to obtain the mass flow rate.With the changing trend of the parameters,the accuracy of the conclusion is further verified by the volume filling rate.(3)The mixing process of materials is mainly carried out in the melting section of the extruder.However,the preliminary mixing of the particles in the solid conveying section can promote further mixing in the subsequent melting section.In this article,HDPE and LDPE are selected.The solid conveying section of the machine is mixed and simulated,the data that meets the conditions are counted,and the deviation standard deviation function formula is imported.The smaller the deviation standard deviation value obtained,the better the particle mixing effect,and the comparison of different extruder structures and particle shapes The degree of mixing provides a strong basis for the initial mixing of the solid conveying section.