| Counter-rotating intermeshing twin-screw kneader is widely used for its strong ability of conveying, extrusion and metering conveniently, screw rotor element as the key component of a kneader, the screw rotor configuration directly affect the action of shear and tensile for the blending materials, so may get a different mixed degree and different mechanical properties of the product, and the screw configuration of rotor is fundamentally determined by the end cross-section profiles of rotor, thus it has great significance to research the end cross-section profiles of rotor for the mixing performance of screw rotor.Taking the screw rotors of the twin-screw kneading machine as the research object, study the evolution process of the end cross-section profiles of screw rotor; and from the perspective of flow field which is steady and transient, use the finite element method, carry out some researches on the mixing characteristics of screw rotors with several typical end cross-section profiles; implement the parameter sensitivity analysis for some kind of screw rotor with certain rotors profiles and researched the feasibility of mixed processing for this kind of specific screw rotors with experiment. The specific research work mainly includes the following aspects:1) Firstly, discussed the research background and significance of this article, then made overview summary for current research situation at home and abroad from the aspect of profiles design and performance of screw rotor. Lastly, simple classification of twin-screw kneading machine is introduced.2) According to conjugate enveloping method based on the principle of gear meshing designed the mathematical model of original end cross-section profiles of female and male rotor, meanwhile, the tooth number of female rotor and that of male rotor respective is two and one. To establish a unified mathematical model, which can express the current common end cross-section profiles of screw rotor of twin screw kneader, study the evolution process of the profiles of screw rotor and preliminarily explore the inherent law between the different rotor profiles currently.3) Through establishing the finite element model of flow channel and several kinds of different screw element with typical end cross-section profiles, applying numerical simulation method carry out transverse comparison for the mixing ability of several kinds of typical screw rotor, meanwhile, comparing with several parameters which characterize the distributive mixing ability and dispersive mixing ability of the screw rotors, studying the effect of different end cross-section profiles on the mixing performance, the research results provide theoretical basis for the selection of screw rotors of the actual industrial production.4) For some kind of screw rotor with typical end cross-section profiles, adopt the parameters which characterize what material experience, such as maximum shear rate, the maximum shear stress, maximum mixing index and cumulative residence time distribution, the residence time distribution, analyzes the effect trend on mixing performance of screw rotor with the geometric parameters including center distance, lead, screw edges angle of male rotor and the process parameters contain speed, pressure difference between inlet and outlet and working temperature, furthermore provide the scientific basis for the reasonable design of twin-screw kneading machine and take high efficiency and low energy consumption as the goal to find a set of optimized combination of design parameters and process parameters.5) With the limited experimental equipment for a novel twin screw kneader, through observing the microscopic characteristics of morphology of blend for two kinds of different color masterbatch, verify the feasibility of mixing processing for the twin screw kneader, which taking screw group SD41as rotor components. Meanwhile, provide reference for the research of mixing performance of novel twin screw kneader. |
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