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中南大学学报(自然科学版)

Journal of Central South University

第46卷    第7期    总第251期    2015年7月

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文章编号:1672-7207(2015)07-2446-06
回转窑截面物料运动及力链结构的数值试验
陈辉1,刘义伦1,肖友刚2,李松柏1

(1. 中南大学 机电工程学院,高性能复杂制造国家重点实验室,湖南 长沙,410083;
2. 中南大学 交通运输工程学院,湖南 长沙,410075
)

摘 要: 采用离散单元法从颗粒尺度建立回转窑内物料的运动模型,以球形沙粒为例,通过数值计算,研究回转窑截面上物料的运动模式和力链结构。以Froude数、物料填充角、窑壁摩擦因数为变量,模拟物料的滑移、塌落、滚落、泻落、抛落和离心6种运动模式,模拟结果与实验观测结果相符。研究结果表明:回转窑内物料力链由表层弱力链区域(约占料层厚度10%)和底层强力链区域组成;滑移、塌落、滚落和泻落4种模式中,底层强力链结构稳定,颗粒之间相对静止,表层弱力链断裂和重组频繁,具体运动模式由窑转速和表层力链断裂重组的速度决定;实际转速中,泻落模式的物料颗粒碰撞最强烈。

 

关键词: 回转窑;物料运动;力链;离散元法

Numerical experiments on transverse motion and force chains of solids in rotating cylinders
CHEN Hui1, LIU Yilun1, XIAO Yougang2, LI Songbai1

1. State Key Laboratory of High Performance Complex Manufacturing,
School of Mechanical and Electrical Engineering, Central South University, Changsha 410083 China;
2. School of Traffic and Transportation Engineering, Central South University, Changsha 410075, China

Abstract:Taking account of the interactions between particles, a kinematic model of granular bed in rotating kiln was established using discrete element method based on its particle size. Using spherical quartz sand as bed material, transverse bed motions and particle force chains were studied through numerical calculation of the model. Taking the Froude number, filling angle, and wall friction coefficient as variables, six forms of transverse bed motion observed in experimental tests were simulated: sliding, slumping, rolling, cascading, cataracting and centrifuging. The results show that the force chains within the bed consist of two parts: the surface area with weak chain (about 10% of the bed thickness) and the underlying area with strong chain. In case of sliding, slumping, rolling and cascading, the force chains of the underlying area are stable and the particles are relatively static. However, the force chains of the surface area are broken and restructured frequently, which makes the material particles move downward and mix together. The specific motion is determined by rotate speed and force chain breaking-restructuring speed. Contracts between bed particles in the form of cascading are the most savage for actual operation.

 

Key words: rotating cylinders; transverse bed motion; force chains; discrete element method

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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