Abstract: Pellet mill is one of the important equipment in the feed industry, and its structural parameter has impact on feed molding. In order to further optimize the granulation performance, this article used COMSOL finite element analysis software to analyze and simulate the extrusion process of the material, and designed a set of orthogonal experiments of L9 (34) to study the influence of the inner diameter of the ring die, die hole length, pressure roll diameter and die roll gap on forming performance, then used the weight matrix analysis to obtain a better parameter combination and verified it. The results showed as follows: ① the simulation of the internal model of the granulator could effectively reflect the movement state of the material in actual work. ② The order of the structural factors that affected the granulation performance from large to small was die roll gap, die hole length, pressure roll diameter, ring die inner diameter. ③ The optimal combination of granulation was ring die inner diameter 425 mm, die hole length 54 mm, pressure roller diameter 178 mm, die roller gap 1.5 mm. Compared to before optimization, the molding rate of the pellet mill had been improved. It was concluded that the simulation test and optimization method adopted in this paper had certain practical effects, which provided method reference for the internal molding simulation analysis of the granulator and the subsequent structural design and parameter optimization. 

Key words: pellet mill, COMSOL, numerical simulation, structure parameters, orthogonal test, weight matrix method

摘要： 制粒机是饲料行业重要设备之一，其结构参数影响饲料成型。为了进一步优化制粒性能，采用COMSOL有限元分析软件对物料的挤压过程进行分析模拟，设计L9(34)正交试验研究制粒机环模内径、模孔长度、压辊直径和模辊间隙对成型性能的影响，通过权矩阵分析确定较优的参数组合并加以验证。结果表明：①制粒机内部模型的仿真模拟能够有效地反映物料在实际工作时的运动状态；②对性能影响由大到小的结构因素排序为模辊间隙、模孔长度、压辊直径、环模内径；③制粒最优组合为环模内径425 mm、模孔长度54 mm、压辊直径178 mm、模辊间隙1.5 mm，制粒机的成型速率较优化前得到提升。上述结果表明，采取的仿真试验及优化办法具有一定的实效性，可为制粒机内部成型模拟分析以及后续的结构设计与参数优化提供方法借鉴。

关键词: 制粒机, COMSOL, 数值模拟, 结构参数, 正交试验, 权矩阵分析法