锤片式粉碎机内负压对物料筛分效率的影响研究

Research on the influence of the negative pressure in the hammer mill on the screening efficiency of materials

针对课题组前期研制的锤片式饲料粉碎机筛分效率偏低的问题,现利用离散元法软件EDEM与计算流体力学软件ANSYS-Fluent对该粉碎机中分离装置内的气固两相流场进行耦合计算,获得分离装置内两相流场特性与回料管出口压力的变化规律以及颗粒相的运动规律,详细地分析了颗粒的速度与回料管出口压力的变化规律,以及回料管的回料量与回料管出口压力的变化规律。结果表明,不同工况下的绝大多数的物料颗粒均能到达筛网,在分离装置中呈外密内疏的分布状况;通过对不同回料管出口压力下,回料管回料量的结果进行曲线拟合,当回料管出口负压达到-476 Pa时,筛分效率最高,模拟结果对新型锤片式粉碎机整机性能的提高有一定参考价值。

Aiming at the problem of low screening efficiency of hammer mill developed by the research group in the early stage, the discrete element method software EDEM and the computational fluid dynamics software ANSYS-Fluent were used to calculate the gas-solid two-phase flow field in the separation device of the hammer mill. The characteristics of the two-phase flow field in the separation device, the variation law of the outlet pressure of the return pipe and the movement law of the particle phase were obtained. The variation law of the particle velocity and the outlet pressure of the return pipe, as well as the variation law of the return amount and the outlet pressure were analyzed in detail. The results showed that the vast majority of material particles can reach the screen under different working conditions and are distributed in the separation device in a dense outside and sparse inside. Through curve fitting of the results of the return quantity under different outlet pressures of the return pipe, when the negative pressure at the outlet of the return pipe reaches-476 Pa, the screening efficiency is the highest. The simulation results have certain reference value for improving the overall performance of the new hammer mill.