【作者】 王志强；

【导师】 武佩；

【作者基本信息】 内蒙古农业大学 ， 机械设计及理论， 2009， 硕士

【摘要】 锤片式粉碎机是饲料加工的主要设备,但传统机型一般都受物料环流层的影响,导致物料分离效率低、能耗大、物料被过粉碎等问题。针对以上不足,课题组提出了基于二次粉碎工艺的新型原理锤片式粉碎机,使得物料环流层问题得到了解决,但仍存在物料分离效率低的问题。为了解决这个问题,本文对新型粉碎机物料分离装置内的气流流场进行了模拟与试验研究。结果表明物料分离装置内存在涡流和回流现象,弯管处尤为明显;喂料斗侧的气流速度较高,远离喂料斗侧的气流速度较低,物料分离效率与直弯管过渡角紧密相关。利用FLUENT6.3软件中的Mixture模型对物料分离装置进行了气固两相流模拟。结果表明物料分离装置内固相的分布极不均匀,大多数的颗粒都集中在筛片内侧,且随着物料浓度的增加使得物料难以排出,造成堵料;物料分离装置出口处的负压会使得已过筛的物料产生涡流回旋现象,不利于已过筛物料的排出;颗粒的粒径对固相颗粒顺利过筛有一定的影响,随着粒径的增大物料过筛会变得困难,粒径越小越容易过筛,且浓度的影响大于粒径。更多还原

【Abstract】 Hammer mill is one of the most widely used machine for feed grinding. Normally the traditional hammer mill has the problem of material-air circulation lay, causing the low sieving efficiency, higher energy consuming and material over- grinding.A new-model hammer mill was developed by our research group in the earlier work, in which the problems caused by the materials-air circulation lay had been solved, but the material sieving efficiency was still low. In this paper, the simulation and test on the air-flow field in the material-sieving device of the new-model hammer mill were conducted. It is concluded that there are turbulent flow and reversed flow in it, especially at the corner area, the air velocity near the side of the feeding part is higher than the other side, and the sieving efficiency is related to the corner.The Mixture model in software FLUENT6.3 was used to simulate the air-solid two-phase flow in the material-sieving device, showing that the solid phase distribution is un-uniform, the particles are mainly accumulated in inlet and the inside of the sieve, which cause the difficulties in separating the material , or even the blocking of the material. The negative pressure in outlet causes the turbulent flow, which is unfavorable for the separating of the materials, and bigger particles are more difficult to be sieved. Particle diameter has less influence on sieving properties than the particle content.更多还原