基于泥层高度的耙架扭矩力学模型及机理分析

Mechanics model of rake torque based on sludge height and its mechanism analysis

通过进行不同泥层高度下的连续动态浓密实验,得到压密区尾砂浆的质量分数和屈服应力的变化规律;借助屈服应力与泥层高度的回归关系,并对浓密机耙架进行力学分析,建立不同泥层高度下的耙架扭矩力学模型。研究结果表明:耙架扭矩随泥层高度的变化规律可以分为缓慢—强化—线性3个阶段。结合压密区砂浆存在形式的变化,发现随着泥层高度的增加,压密区尾砂颗粒受到的压力增大,砂浆密度提高并逐渐致密化,导致耙架扭矩在不同阶段内增长规律不同。通过采用扫描电镜观测压密区尾砂浆的微观结构,发现3个阶段内,絮团发生沉积—致密—稳定3种不同形式的变化,并伴随着絮团尺寸的改变,从而最终提高了浓密机耙架扭矩,进一步验证了耙架扭矩力学模型。

Through continuous and dynamic thickening experiments at different sludge heights,the change law of the concentration and yield stress of the slurry in the compaction zone was obtained;Based on regression analysis of yield stress and sludge height and mechanical analysis of rake frame,the mechanical model of rake torque with different sludge heights was established.The results show that with the increase of sludge height,the change law of rake torque can be divided into 3 stages:slow stage,strengthening stage and linear stage.The change of the existing form of slurry in compaction area shows that with the increase of sludge height,the pressure of tailings particles increases,and the density of slurry increases and slurry is gradually densified,resulting in different growth rules of rake torque at different stages.Through observing the microstructure of the slurry in compaction area by using scanning electron microscope,it is found that in the 3 phases,flocs change in three different forms:sedimentation,densification and stability.With the change of floc size,the rake torque is ultimately improved,which verifies the mechanical model of rake torque.