Study On Melt Transport Balance Problem Of Different Assembled Screw In Extrusion Granulator

The intermeshing co-rotating twin screw extruder (ICTSE) has been more widely used in the plastics processing and modification, and it has became an important core equipment of plastic extrusion granulation. Driven by the demand of market, the intermeshing co-rotating twin screw extrusion granulator (ICTSEG) towards the high-output, high-efficiency, large-scale and low-power direction. Although the study of theory about extrusion processing of ICTSE has been deepening, but there are more problems still need to be studied. Base on the theory about extrusion processing of twin screw extruder, it is very significant to improve the design and applied level of extrusion granulator by carrying out the study on the design theory and design method of assembled screw of ICTSE.The melt transport zone in ICTSEG was researched in this thesis. The flight element amendment, melt transport balance and melt filled length of assembled screw was studied by numerical simulation and experiment.Though the three dimensional modeling technology, common methods of amendment has been analyzed in detail in this thesis, and a program was compiled for calculation of different amendment methods. Results showed that the uniform meshing gap and smooth connection of flight elements with different pitch were obtained by using the amendment base on normal direction, axial section and datum pitch.In this thesis, researches focused on the design of assembled screw of ICTSEG. And the quantitative model for melt transport was built by numerical simulation with several geometric similarity and dissimilarity screw element channels. The pressure distribution against axial of assembled screw channel could be calculated by using the quantitative model, and the melt filled length on the steady extrusion condition could also be speculated. The assembled screw optimized by the melt filled length could improve the efficiency of twin screw extruder, and provided reference for the design of screw of ICTSEG.The study of assembled screw channel by numerical simulation and experiment showed that, the calculated result of melt filled length was basically identical with the simulation result, the error between calculated result and experimental result was 2.5 percent.Under process condition of extrusion granulator, the screw parameters in melt transport zone could be designed by applying the quantitative model, and the model could provide reference for the design of screw.