基于颗粒缩放理论的垂直螺旋输送离散模拟

Discrete Simulation of Vertical Screw Conveyor Based on Particle Scaling Theory

利用相似理论和量纲分析进行颗粒缩放,将粒径0.5 mm的铸铁煤粉颗粒放大至2 mm,进行虚拟实验标定放大颗粒的基本接触参数,用离散单元模型模拟垂直螺旋输送中的颗粒运动,验证颗粒缩放法的准确性.结果表明,螺旋转速为500,550,600,650 r/min时,颗粒轴向速度和圆周速度增大,最大轴向速度位于中上部,处于叶片边缘,分别为0.486,0.535,0.596,0.657m/s,超过螺旋叶片半径区域的颗粒轴向速度明显减小;相同填充率下,装置出口处质量流率、颗粒轴向速度模拟值和实验值基本吻合,满足相似理论.

With the principles of similarity and dimensional analysis,the cast iron pulverized coal was enlarged from 0.5 mm to 2 mm.The virtual experiment was carried out to calibrate the basic contact parameters of scaled particles.The simulation of particle movement in vertical screw conveyor with discrete element model was carried out to verify the exactness of the scaling method.The results showed that when the screw rotation speed is 500,550,600,650 r/min,particle axial velocity and peripheral speed is increased.The maximum axial velocity is in the upper part and on the verge of blade,respectively 0.486,0.535,0.596,0.657 m/s.The axial velocity decreases obviously in area more than spiral radius.Compared with simulation and experiment,the mass flow rate in the device outlet and particle axial velocity is true on the whole and meets the principles of similarity under the reasonable approximations.