中文摘要：

混合工序是固体火箭发动机制造的重要工序，而立式捏合机是完成该工序的关键设备。捏合间隙是影响立式捏合机混合性能的关键几何参数，包括：桨叶之间的间隙，与桨叶的安装中心距呈正比；空心桨叶与捏合锅内壁之间的间隙等。根据实践需求，分析捏合间隙与混合性能的关系，是立式捏合机设计中的一个重要问题。

英文摘要：

The effect of kneading clearance on the mixing performance of vertical kneading mixers was investigated by using the CFD methods. Firstly, the mixing field in the kneading tank was simulated numerically after analyzing the movement of mixer blade and the rheological properties of the material. Next, some macro mixing performance evaluation indices of the device were proposed. Lastly, the effect of kneading clearance on mixing performance was studied. The results indicated that a small kneading clearance could improve the mixing performance of vertical kneading mixers and better kneading efficiency could be achieved with a uniform kneading clearance.