Abstract

Objective Particle mixing technology is widely applied in industrial processes across various sectors，including steel， energy， food， pharmaceuticals， chemical engineering， mining， and ceramics. Mixing refers to the process in which two or more materials of different properties are forced into each other’s spatial domains under external forces. The velocity， direction， and position of each particle constantly change， resulting in a new particle distribution and uniform dispersion of various particle types throughout the entire volume and local regions. To meet industrial needs， different types of particles are often blended to improve material performance. Polypropylene （PP） is one of the most widely used plastic particles， but it has low thermal resistance and poor toughness. In industrial applications， nylon 6 （PA6） is often added to PP particles to improve toughness. The mixing of PP and PA6 particles usually requires advanced mixing equipment. Due to differences in working principles， drum geometry， operating modes，and mixing methods， the particle motion patterns and mixing time vary significantly among different mixers. Drum-type mixers are widely used due to their simple structure， reliable performance， and high throughput. Therefore， drum-type mixers are well suited for mixing PP and PA6 particles. This paper aims to address the problem of uneven mixing of PP and PA6 particles in drum-type mixers and to identify the optimal structural parameters.

Method The mixing model of the drum-type mixer was analyzed， and the mechanical model of the particles was also examined. A three-dimensional model of the drum-type mixer was established using the Discrete Element Method （DEM）. In the EDEM software， material parameters for PA6 and PP particles were set. Under a rotational speed of 40 rpm and counterclockwise rotation， the mixing process of 3 kg of PA6 particles and 1 kg of PP particles was simulated. The mixing performance of the two types of plastic particles under striped structures with different numbers of layers， heights， and angles was analyzed， along with the mixing state of the particles at different time intervals. The number of particles in each grid cell at every time step was exported from EDEM， and MATLAB was used to calculate the Lacey mixing index. This allowed for an analysis of the variation in mixing uniformity throughout the mixing process. Finally， three-level and three-factor orthogonal experiments were conducted to determine the optimal structural parameters， and the simulation accuracy was validated by experimental data.

Results and Discussion The analysis results indicated that the mixing process in the drum-type mixer exhibited distinct characteristics at different stages. In the initial stage， the mixing index increased rapidly； in the intermediate stage， the rate of increase slowed down； and in the final stage， the index gradually stabilized. The number of pairs， height and angle of the band-shaped strips had different effects on the mixing index. The mixing effect of the three pairs of band-shaped strips is higher than that of other pairs， and the mixing index is 0.884 1. When the logarithm of the band-shaped strips exceeds three pairs， the mixing index will decrease instead. The mixing effect of the band-shaped strips with a height of 3 cm is higher than that of other heights， and the mixing index is 0.904 5. The mixing index increases with the increase in the height of the band-shaped strips， but the increase amplitude gradually decreases. The mixing effect of the band-shaped strips with an angle of 50° is higher than that of other angles， and the mixing index is 0.827 6. As the angle of the band-shaped strips increases， the mixing index of the particles increases， but the increase amplitude gradually decreases.

Conclusion A three-level， three-factor experimental design was conducted using the different number of pairs， height， and angle of the band-shaped strips as factors， with the mixing index as the evaluation metric. By analyzing the 9 sets of experimental results obtained from the orthogonal experiment， it was found that the influence of different factors on the mixing index， from greatest to least， is the height of the banded strips， the number of banded strips， and the angle of the banded strips. When the number of band-shaped strip pairs was 3， the strip height was 3 cm， and the strip angle was 35°， the best mixing performance of the drum-type mixer reached 0.908 6， with a simulation-to-experiment error of 4.297%.

Keywords： drum-type mixer； particle mixing； mixing uniformity； discrete element method

Get Citation:CHEN Shen， ZHANG Luyang， YU Jianfeng， et al. Design and simulation of drum‑type mixer based on EDEM［J］. China Powder Science and Technology， 2026， 32（3）： 1-10.

Received: 2025-04-25 .Revised: 2025-07-10,Online: 2025-09-30.

Funding Project:国家自然科学基金项目，编号：51905215；江苏省研究生科研与实践创新计划项目，编号：KYCX23_2553；江苏省食品先进制造装备技术重点实验室自主研究课题资助项目，编号：FMZ202302。

First Author:陈深（2001—），男，硕士生，研究方向为粉体智能装备。E-mail：1290593895@qq.com。

Corresponding Author:俞建峰（1974—），男，教授，博士，博士生导师，研究方向为粉体智能装备。E-mail：robotmcu@126.com。

DOI：10.13732/j.issn.1008-5548.2026.03.002

CLC No:TB44            Type Code: A

Serial No:1008-5548（2026）03-0001-10