非对称双螺杆端面构型对混合行为的影响

Effect of Cross-Section Shapes of Non-twin Screws on Mixing Performance

给出了3组等速旋转同向非对称自洁型双螺杆端面造型,并对3种螺杆构型与普通双螺杆端面混合行为进行了对比。基于Ployflow软件网格叠加技术,以满足Carreau定律的纯黏性流体为加工对象,得出速度场分布。运用粒子示踪技术,探索不同位置混合性能的差异。结果表明:新型非对称双螺杆中粒子分散时间较短,且较均匀。采用累积分散准数表征分散混合,分离尺度、界面拉伸长度表征分布混合能力,分析了不同构型混合性能的差异。

Three groups of cross-section geometries of the novel co-rotating non-twin screws with the same speeds were presented. The mixing behaviour of three configurations were compared with that of the traditional twin-screw with two tips. Based on the mesh superposition technique provided by Polyflow, the velocity field were acquired with the fluid concerned obeying the Carreau flow model. The different mixing performances of the fluid located at different positions were investigated adapting partiele tracking technology. The results showed that the particles in the novel non-twin screws dispersed in a relatively short time and more uniform. The mixing index was used to characterize dispersive mixing, and segregation scales along with length stretch of the interfaces randomly distributed in the flow domain were used to characterize the distributive mixing. The differences in mixing performance among different configuration groups were analyzed.