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The Theoretical Study On Forming Process In The Underwater Pelletizing Die Plate

Posted on:2014-11-27Degree:MasterType:Thesis
Country:ChinaCandidate:X F LiuFull Text:PDF
GTID:2251330398483277Subject:Chemical Process Equipment
Abstract/Summary:PDF Full Text Request
With the rapid development of world petrochemical industry, increasing demand for polypropylene-based materials in the international market, which requires high capacity, cost-effective granulation equipment. Pelletizing Die plate is one of the key production parts directly influence product quality grain particles in large-scale underwater cutting equipment.Die plate in the Environment of the internal polymer extrusion, the heat-conducting oil heating and the cooling of the cutting water, the entire Die plate stress and strain will have a serious impact on the life of the Die plate, the surface deformation, pelletizing quality and the cutter life. The vast amount of die hole number within the die leads to its internal flow field inhomogeneity of polymer, which is a major factor affecting the length of grain products. Die plate subjected to the role of multiple physical field, its internal temperature field is very complex, the instability of the temperature field interested in the impact polymer solidification, the solidification of the polymer can affect the diameter of the extruded particles of the size of the mold causing severe hole to plug. Therefore, the Die plate stress and strain, extrusion uniformity, the polymer solidification study in the Die plate, have great significance to the extrusion granulation process. In this paper, based on the3D modeling analysis method, Die plate stress, the polymer flow, thermal oil flow, temperature field of Die plate have been studied. The main tasks are as follows:1. The three-dimensional model of the Die plate is established, heat transfer module in ANSYS-Fluent and Static structural analysis module was used. By two ways of structure parameters and process parameters from the Die plate design thermal-solid coupling was calculated. The Conclusion is that: The Die plate’s temperature rise will cause a large thermal expansion, Die plate field inhomogeneity causes a pelletizing surface have a greater stress concentration; the deformation of Die plate, separately by the preload, the polymer pressure, the oil pressure deformation, is small. But it can also produce stress concentration in the diced surface, eventually leading to the maximum stress in the diced surface of the Die plate, the maximum deformation at the edges in the Die plate; pre-tightening force and heat conducting oil temperature can be produced main effect on the stress and deformation. The stress and deformation cased by the Die hole diameter, cross-sectional area of heat conduction oil channel extrusion die hole on the Die plate is relatively small.2. The finite element analysis software Fluent was used to simulate polymer extrusion speed in every die hole, BP neural network was used to combine the optimal design theory to draw the die plate model hole forming length design principles. When the stereotypes length is the same, the flow rate of each die hole distribution presents opening downward parabolic law and the flow rate is the largest one in the intermediate position; after BP neural network optimization, when die extrusion flow uniformity, die hole shape the opening up of the parabola segment length distribution are studied.3. The common abnormal condition causes and changes in process conditions on the Die plate temperature and granulation quality are studied for extrusion Die plate. By liquid-solid coupled fluid flow and heat transfer calculations, that solidification of polymer in fractional distribution of the Die plate image to simulate how different changes of coagulation State structural parameters and process parameters.4. Through the small underwater pelletizing platform of solidification experiments, obtained polymer solidification in actual Die plate, and compared with theoretical study of polymer solid fraction, to verify the theoretical research, and draw the reason of die hole blockage. The conclusion, based on the recommendations, can be used to improve the Die plate.
Keywords/Search Tags:the pelletizing Die plate, Die plate large deformation, BPneural network, extrusion uniformity, solidification plugging, pelletizing quality
PDF Full Text Request
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