移动床中固体颗粒流动的实验研究和数值模拟

Experiments and Simulation for Particles Flow in the 2-D Moving Bed

研究了二维移动床内的固体颗粒流动状况,考察了流速、颗粒特性和流场的几何形状对移动床内固体流动特性的影响,并采用"运动模型"进行数学模拟,通过与实验数据的比较,分析了模型中参数B值对模拟结果的影响。结果表明,颗粒的质量流速对移动床内流动区域的形状没有影响,而颗粒的休止角的大小对移动床流动区域的形状影响较大,随着颗粒休止角度增大,流动区域变陡,死区变大。颗粒流动的"运动模型"在B=2.5 dp时,可以较好的描述固体颗粒的流动;但是对于挡板位于移动床底部中心(倒漏斗形流场)颗粒由两边流出的情况,模拟结果与实验值相差较大,通过对模型的分析,得知运动模型不适用于该情况。

The flow characteristics of solid particles in 2-D moving bed were studied experimentally and theoretically. The effects of mass velocity, property of particles and the shape of moving bed on flow pattern were examined. A kinematic model was used to simulate the particle flow. Effect of model parameter B value on simulation results was studied and an appropriate B value of B = 2. 5dp was obtained. The kinematic model described the solid flow well. Experimental and calculated results showed that mass velocity of solid particles had no effect on flow pattern but the repose angle of solid particles affected the flow pattern evidently. The time line became more sharp - angled with increasing repose angle, and dead zone became larger. The model gave better description for the solid flow in the moving bed with solid discharging at the central part of the bed bottom than that at the peripheral part. It was concluded that the kinematic model was not applicable to simulating particle flow of moving bed with solid discharging at the peripheral part of the bed.