内置活动内构件回转窑内二元颗粒的运动混合研究

摘要

The motion and mixing of large particles and small particles in rotary kiln installed with unfixed internals was simulated with discrete element method(DEM). The motion trajectories and motion mode of particles were investigated when installing unfixed internals of different lengths(the rotational speed of rotary kiln,the width and thickness of unfixed internals were constant). The contact number index was used to compare the mixing degree of binary particles in rotary kiln installed unfixed internals of different lengths. The results indicated that when the lengths of unfixed internals were 0, 13mm,21mm,29mm and 37mm,the longer the length,the larger the ergodic region of tracer particle's motion trajectory,the smaller the difference of sparse area and dense area of tracer particle's motion trajectory. The tracer particle's motion trajectory was more disorder when installing unfixed internals. The motion mode of particles transformed from rolling to slumping due to the existence of unfixed internals. The disturbance and stirring of unfixed internals could enhance the mixing of large particles and small particles effectively. There is an optimal length of unfixed internals for enhancing mixing of binary particles.%采用离散单元法(DEM)对内置活动内构件回转窑内二元颗粒的运动混合进行了数值模拟.探讨了添加不同长度活动内构件时(回转窑转速、活动内构件宽度及厚度均固定)示踪颗粒的运动轨迹以及颗粒整体的运动模式.用接触数指标来定量评价颗粒的混合程度,比较了添加不同长度活动内构件时回转窑内二元颗粒的混合程度.结果表明:当活动内构件长度分别为0、13mm、21mm、29mm和37mm时,长度越长,示踪颗粒运动轨迹的遍历区域越大,运动轨迹稀疏区和密集区的差别越小,比起无内构件,添加活动内构件时颗粒的运动方向更加随机,运动轨迹更加紊乱.因活动内构件的存在,颗粒的运动模式由滚落模式变为阶梯模式.活动内构件的扰动和搅拌作用可以有效增强二元颗粒之间的混合.活动内构件存在一个最优长度,过长或过短都不能获得最理想的增混效果.