Abstract: The dynamic mixer is the mainstream of today's mixing equipment, and the mixing effect not only affects the production efficiency of the equipment, but also directly determines the performance of the final product. Among them, the structure of the mixing element in the dynamic mixer directly determines its mixing effect on the processed material. Due to the complex structure of the dynamic kneading mixer, the theoretical research on its mixing characteristics is very limited. In this work, the blade structure of the horizontal mixer was optimized and improved, and the structure design of the main and auxiliary blades was adopted to improve the mixing effect of the mixer. By constructing the three-dimensional model and finite element model of the mixer with a new type of blade structure, the mixing characteristics of the mixer were investigated by means of numerical simulation using the computational fluid dynamics software Polyflow, and the influence of blade speed on the mixing performance of the mixer was analyzed. Mixing index, separation scale, average tensile rate, logarithmic tensile rate, and cumulative depolymerization power were used to characterize the dispersion and distribution mixing ability of the mixer, and the accuracy of numerical simulation results was verified by visual experiments. The results of simulation and experiment showed that the simulation results were consistent with the visual experiment results. The material flow type in the mixer with the new blade structure was shear flow, accounting for about 85%. The average tensile rate and average logarithmic tensile rate in the flow field were always positive, indicating that the mixer had good distribution and dispersion mixing ability. The increase of blade speed had little influence on the flow type of materials in the flow field, but can effectively improve the performance of distributed mixing and dispersed mixing of the mixer. When the blade speed increased from 30 r/min to 120 r/min, the average separation scale of the mixer's transverse distribution mixing decreased by 50%, and the average tensile rate increased by 300%. The average cumulative depolymerization work increased by 1500%.

Key words: blade structure, computational fluid dynamics, visualization, mixing characteristics

摘要： 对卧式混合器的桨叶结构进行开发，采用主、副叶片组合式的结构设计以提升混合器的混合效果。采用计算流体力学软件Polyflow探究了混合器的混合特性，分析了桨叶转速对混合器混合性能的影响，采用混合指数、分离尺度、平均拉伸率、对数拉伸率和累积解聚功表征了混合器的分散和分布混合能力，通过可视化实验验证了模拟结果的可靠性。结果表明，模拟结果与可视化实验结果呈现出一致性，新型桨叶结构的混合器内物料流动类型以剪切流动为主体，占比约85%，流场内平均拉伸率和平均对数拉伸率始终为正值表明其具有较好的分布和分散混合能力，桨叶转速的提高对流场内物料的流动类型影响较小，但能有效提高混合器的分布混合和分散混合的性能，当桨叶转速从30 r/min提高到120 r/min，混合器的横向分布混合平均分离尺度下降了50%，平均拉伸率提高了300%，平均累积解聚功提高了1500%。

关键词: 桨叶结构, 计算流体力学, 可视化, 混合特性