Study On Extrusion Mechanism And Equipment Of Rotary Combined Single Screw Extruder

Single-screw extruder has been widely used in many fields such as plastic,chemical and pharmaceutical applications.The single-screw extruder with the extrusion and puffed technology is mainly used in the puffed food industry.However,due to the progress of the times,the traditional single-screw extruder can not keep up with the needs of the industry development.As the core component of the single-screw extruder,its configuration is an important factor affecting the performance of the extruder.Therefore,studying different screw structure and shape has great significance to improve the extrusion performance of single screw extruder.This paper first introduces the theoretical knowledge of single-screw extruder and establishes a 3D solid model of combined single-screw extruder with mixing and reverse screw elements using Solidworks modeling software.Secondly,make reasonable assumptions according to the flow characteristics of the materials and establish the corresponding numerical model.Finally,using the finite unit method as the numerical simulation method,the flow field of two single-screw extruder was grid by ICEM CFD and introduced into CFX software to analyze the influence of different screw configurations on the extruder performance according to the obtained pressure field,speed field,shear stress field and the residence time of materials in the flow channel.Meanwhile,the influence of screw speed on the extruding mass flow of two single-screw extruder was studied,and the comprehensive influence of different process parameters on the performance of rotary combined single-screw extruder was studied by orthogonal test method.The analysis of the field quantity of the flow field shows:the mixing element can destroy the continuous stability of the material flow,reduce the material flow speed,and increase the residence time of the materials in the flow field.The reverse thread element has a strong construction pressure capability.Adding the mixing element and the reverse thread element to the ordinary screw can improve the construction capacity,shear capacity and mixing ability of the single-screw extruder.The research results provide a theoretical basis for the design and manufacture of single-screw extruder.The relationship between extrusion mass flow and screw speed of common rotary single-screw extruder and rotary combined single-screw extruder can be obtained by single factor analysis.By comparison,the extrusion mass flow of rotary combined single-screw extruder is higher than that of ordinary rotary single-screw extruder.By means of orthogonal test,the influence degree of different factors on the performance of extruder can be obtained,and through comprehensive analysis,A₁B₂C₂is the best scheme in processing.The research results of this paper provide a theoretical basis for the design and manufacture of a single-screw extruder.