The Research On Numerical Simulationof The PVC Wood-plastic Single-screw Extruder’s Melting Section

Wood-plastic composite is a new type of material booming at home and abroadin recent years. Its sheet or shaped can use thermoplastic plastics as the matrix,adding wood powder accounting for20to85percentage and various processing aids,then use high speed mixer to mix, lastly use extrusion, molding, injection molding orother plastic processing technology to produce. It has the excellent properties of woodand plastic and many properties wood and plastic don’t have, for example fireproof,waterproof, mothproof, non-toxic, pollution-free and so on. Its use decreases the harmof waste plastic on the environment and improves the comprehensive utilization rateof timber. PVC wood-plastic is a kind of it, using polyvinyl chloride as the matrix.At present, the domestic wood-plastic composite extrusion equipment’sexploitation is by adjusting some parameters of the plastic extrusion equipment, basedon the experience. There are few equipment’s exploitation aiming at the material’sproperties. Its theory is still using relevant theories of plastics extrusion molding. Butthere are big differences between wood-plastic composite and plastic. It results in thelow efficiency, high energy consumption, bad product quality and big labor intensityof the equipment. The lag of wood-plastic composite dedicated productionequipment’s research and development and manufacture has became a bottleneckrestricting the development of China’s wood-plastic industry. Studying the extrusiontheories of wood-plastic and then using them to guide the exploitation of equipmentare very important to wood-plastic industry’s development.Melting section is the most important part of single-screw extruder. The articleincludes the following parts. Firstly, get the parameters the simulation needs throughexperiments and use MATLAB to get the fitting viscosity model parametersaccording to rheological experimental results. Secondly, build three-dimensionalmodel of flow channel. Thirdly, on condition of the setting of the boundary condition,use the solidification&melting model in FLUENT to simulate and get the meltingprocesses of the melting section. Fourthly, choose some main parameters of screwand the process conditions. While keeping other parameters and process conditions,change a parameter of screw or a kind of process conditions, taking three differentvalues of each screw parameter and process condition, and establish various cases ofnumerical simulations. Through the analysis of the results, get the influences of screwparameters and process conditions on the flow field and melting processes of the flowchannel.