竖直振动管中颗粒的上升运动

通过实验和数值模拟研究了竖直振动管中颗粒的受激运动.将一直管插入静止的颗粒料层中,并在管内预填充一定高度的颗粒,对直管施加竖直振动.振动强度较弱时,管内的颗粒在重力作用下向下运动;当振动达到一定的强度时,管内颗粒不下降反而克服重力的作用向上运动,随着振动强度的进一步提高,即使不在管内预填充高于颗粒床层的颗粒,颗粒也会沿着振动管逆重力向上运动.颗粒的上升高度与运动速度强烈依赖于振动强度.通过高速相机记录颗粒和直管在单个振动周期内的运动,并结合离散元(DEM)法模拟管内颗粒的受力变化规律,给出了颗粒上升的机理.此研究对实现散体物料的定向输运提供了一种新方法.

The rising motion of grains in a vibrating pipe

The rising motion of grains in a vibrating pipe is studied experimentally and by DEM (discrete element method) simulations. A pipe is partially inserted into a static granular layer. With the pipe initially filled with a certain height of grains, when the pipe is set into vertical vibrations, grains in the pipe will rise along the pipe and the motion will be finally stabilized at a certain height. The rising height and the speed of motion are strongly dependent on the vibration strength. By using a high speed camera and through DEM simulation, the trajectory of individual grains and the force acting on the grains in each vibration cycle can be obtained. A force-based mechanism for this rising motion is proposed. During vibrations of the pipe, the grains in the pipe are compacted and loosened alternately, and the force of the pipe and the grains varies periodically, thus leading to the rising motion of grains. A new possible way of continuously transporting grains is presented in this work.