新型螺带桨叶结构对颗粒混合效果的影响

Influences of new spiral band paddle structure on particle mixing effect

为提高立式锥形混合机的颗粒混合效果,设计一种新型错位断带式螺带桨叶结构;通过数值模拟方法研究错位断带式和连续式2种螺带桨叶结构的颗粒混合过程,并探讨错位断带式螺带叶片上、下层叶片的错位距离、错位高度和螺距比对混合效果的影响;通过实验验证模拟结果的正确性。结果表明:根据实验结果计算得出的错位断带式和连续式螺带桨叶结构的混合机内颗粒的平均混合指数分别为0.922、0.861,根据模拟结果计算得出的平均混合指数分别为0.985、0.941,实验结果比模拟结果偏低,错位断带式螺带桨叶结构的混合效果更佳;错位断带式螺带桨叶结构能够增强颗粒的对流过程,能提升颗粒的混合效果;增加错位距离对混合效果没有明显的影响;当错位高度为30、60、90 mm时,在混合时间为7、7、8 s时就全部达到颗粒的完全混合;当螺距比为1时,混合效果最好。

In order to improve the particle mixing effects of the vertical cone mixer,a new type of spiral band paddle structure with dislocation broken belt was designed.The particle mixing process of two types of spiral blade structures,namely dislocation broken belt type and continuous belt type were studied by numerical simulation method.The influence of dislocation distance,dislocation height and pitch ratio of the upper and lower paddle of spiral blade with dislocation broken belt type on the mixing effect were discussed.The correctness of the simulation results was verified through experiments.The results show that the average mixing indexes of particles in the mixers with dislocation broken belt and continuous spiral belt paddle structures calculated according to the experimental results are 0.922 and 0.861 respectively,while the average mixing indexes calculated according to the simulation results are 0.985 and 0.941 respectively.The experimental results are lower than the simulation results,but the mixing effect of the dislocation broken belt spiral belt paddle structure is better.Dislocation broken belt type can enhance the convection process of particles and improve the mixing effect of particles.Increasing the dislocation distance has no obvious influence on the mixing effect.When the dislocation height is 30,60 and 90 mm,the particles will be completely mixed when the mixing time is 7,7 and 8 s respectively.When the pitch ratio is 1,the mixing effect is the best.