| Screw strong shear force chemical reactor, which is a new type of chemical reaction extrusion device, with its unique strong shear effect, is to provide a new kind of processing equipment for the machining of the polymer in polymer modification. This article is researched from three aspects, which are the design principle of screw strong shear force chemical reactor, the optimization of the whole machine structure and strong shear type. And the basic theories are the polymer chain scission mechanism, the grafting theories and the principle of chemical reaction. Numerical simulation method is used to analyze the effects of barrel structural parameters and strong shear section of screw and barrel changes on material shear, for getting the most optimized screw strong shear force chemical reactor.By the mechanism of polymer chain scission and mill type chemical reactor design principle, we introduced the "mill type" design idea into the single screw extruder screw and barrel. That is to say, strong shear section is increased at the exit of the ordinary single screw extruder. In strong shear area of screw and barrel, strong shear field is formed due to the high speed rotating, making the polymer melt have an effect on the strong shear force in the advancing process after this period and the polymer molecular chain break. On the basis of this thought, we finished the overall design of chemical reactor of strong shear section and screw strong shear force reactor.According to the theory of molten polymer molecules, the design principles of conventional single screw extruder screw and the screw shape parameter of material melt in the flow passage under the influence of velocity, pressure and extrusion rate, we finish the specific design of the strong shear force of screw in the chemical reactor strong shear section of screw and barrel shape according to this theoretical basis.According to the theory of single screw extruder melting and fluid flow mechanism, we get the velocity field, pressure field and shear rate distribution in the strong shear section by using the method of finite element numerical simulation analysis for material flow.Firstly, the author used the method of numerical simulation to analyze different screw geometry parameters to the material flow of strong shear stress and shear rate distribution when the strong shear segment barrel is the light tube. It is concluded that when the barrel is the light cone, screw arris cross section is the triangular shape and the screw arris quotas and screw arris angle increases.Then, according to the selected shape of the screw parameters, the author analyzed the effect of spiral groove of geometric parameters on the strong shear section of the material flow and shear rate distribution when the barrel wall open have screw groove. It is concluded that when barrel inner surface processing have a right-hand is triangular screw groove, screw the crib is3and screw groove Angle is30, under the condition of the screw shape determined, good shear effect can be obtained.Finally, in order to determine the strong shear section of screw and barrel shape, the author made the shape parameters of the screw and barrel restructure. By comparing the pressure of the flow field under different parameter combinations and shear rate field, the selected strong shear section of screw and barrel of the geometric parameters were:trapezoidal screw spiral rib section, trapezoidal machine barrel screw groove section, quotas are5head and angle is30.This screw strong shear force chemical reactor in this study has a wide range of application space for polymer modification of polymer processing and provides a new way of thinking to broken links of polymer. The strong shear effect produced in this research can enlarge polymer chain cutting many times, reducing the average molecular weight of polymer, and exposing the end free radical graft modification so as to improve the performance of the polymer or output of new polymer materials。... |
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