Numerical Simulation Of Flow Of Rubber Compounds In Partially Filled Internal Mixer And Simulation Of Conveyor Belt Vulcanizing Process

Most numerical simulations of the flow in an internal mixer are based on the assumption that the internal mixers are totally filled with rubber compounds. However, in fact, the internal mixers are only partially filled with rubber compounds, Consequently resulting in the establishment of a free surface flow regime inside the mixer and posing many challenges for researchers in simulating the flow in the internal mixer. In this study, the volume of fluid (VOF) method and the dynamic mesh technology of computational fluid dynamics software, FLUENT, were used to simulate the flow of rubber compound in a partially filled internal mixer. To improve simulation accuracy, we manually re-meshed the flow field every 18 degrees, according to the calculated transient location of the rubber compound. Thus, we obtained the transient distribution of the rubber compound in the internal mixer as the rotors rotated.The flow of rubber compounds in non-intermeshing counter rotating internal batch mixers equipped with traditional 2:1 rotor and new 4:1 rotor over the course of mixing was simulated using POLYFLOW software. The resulting velocity profiles were used to calculate the paths of material points in order to make an quantitative comparison of the mixing efficiency between the two rotors. Statistical results indicate that the shearing-type new 4:1 rotor is more effective and efficient than traditional 2:1 rotor in distributive mixing, while keeping high efficiency of the dispersive mixing.In this paper, a commercial finite element code, ABAQUS, was employed to simulate the temperature history of a EP canvas conveyor belt in the vulcanizing process. In order to calculate the degree of cure(DOC) throughout a conveyor belt, a user-defined subroutine, UVARM, was programmed. The vulcanizing reaction heat was also included using another user-defined subroutine, HETVAL. we can get the distributions of temperature and degree of cure in the conveyor belt at any time during vulcanizing process, the simulated results show that the vulcanizing reaction heat has great influence on the vulcanization temperature field. The influence of the vulcanizing temperature and vulcanizing time on the degree of cure fields of the conveyor belt were explored though numerical simulation, and an optimized vulcanizing process was proposed according to the analysis results. Under the condition of invariable in vulcanizing temperature, the vulcanizing time decreased from 40min to 32min, saving up to 8min. Reducing the temperature of hot plate by 3K, and the vulcanizing time shorten from 40min to 38min, and the simulated results show that the optimized vulcanizing process can improve the vulcanization quality of conveyor belt, reduce energy consumption and increase the production efficiency.