【摘要】 为探索粉体卸料过程中出现堵塞、脉动及鼠洞等问题的内在原因，掌握粉体卸料特性与应力特性间的关联机制，本文利用有机玻璃实验料仓对不同粒径煤粉进行了卸料实验研究。使用布置于料仓侧壁的微型应力传感器获得了壁面法向应力特性；通过称重传感器得到了卸料质量流率特性。结果表明：较大粒径的煤粉出料稳定，出料时底部壁面法向应力迅速下降且存在两个局部峰值，出口处壁面法向应力处于高频振荡的动态平衡状态；较小粒径的煤粉在出口处易结拱，进而造成了出口处不规则的应力变化，且破拱后产生不受控洪流。分析可知：料仓壁面处的粉体静止区能够消除颗粒-壁面粘滑运动导致的应力振荡。对于较大粒径的煤粉，应力变化由卸料时锥段底部出现粉体稀疏区、应力沿纵向存在的应力状态转变和静止区滑落引起。小粒径煤粉内聚力较大，致使出料堵塞。更多还原

【Abstract】 To explore the causes of clogging, pulsation and rat holes in the powder discharge process, and to understand the correlation mechanism between the powder unloading and powder stress, the discharge behavior of pulverized coal with different particle sizes were experimentally studied in a plexiglass silo. The stress characteristics were obtained through the micro stress sensors arranged on the silo wall. The mass change law was acquired from the load cells. The results showed that the pulverized coal with larger particle size can be discharged stably while the normal stress near the bottom wall decreased rapidly and there were two local peaks. Meanwhile, the wall normal stress near the outlet was in a dynamic balance state with high-frequency oscillation. The pulverized coal with the smallest particle size easily arched at the outlet, resulting in irregular stress changes there and uncontrollable powder flood flow after the arch broke. Further analysis showed the powder stagnant zone near the silo wall can eliminate the stress oscillation caused by stick-slip motion between particles and the wall. For the pulverized coal with larger particle size, the sparse area at the bottom of the cone, the transformation of stress state and the sliding of powder stagnant zone would lead to the change of the normal stress during discharge. The pulverized coal with smaller particle size had larger cohesion, which obstructed the powder discharge.更多还原