撞击流中颗粒运动行为的CFD-DEM模拟

CFD-DEM simulation of particle motion behavior in impinging stream

为了研究撞击流反应器内非同种颗粒相间的运动扩散规律,考虑颗粒的旋转及碰撞,建立三维欧拉-拉格朗日模型,结合计算流体力学和离散单元法模拟非同种颗粒相在气固两相撞击流场合下的颗粒运动扩散状态,分析颗粒在撞击流流场中的运动轨迹以及不同气相入口速度及喷嘴间距条件下的颗粒间相互碰撞次数的变化。结果表明:在同等条件下,喷嘴间距增大,2种颗粒之间的碰撞次数呈先增大后减小的趋势,在喷嘴间距与喷嘴直径之比为4的时候达到最大;气相速度增大对颗粒在撞击区的碰撞次数影响不大。

In order to study the law of movement and diffusion between different particle phases in an impinging stream reactor,considering the rotation and collision of particles,a three-dimensional Euler-Lagrangian model was established,and a combination of computational fluid dynamics and discrete element method was used to simulate the particle movement and diffusion state of two kinds of particle phase in the gas-solid two-phase collision stream.The trajectory of particles in the impinging flow field and the changes in the number of collisions between particles under different gas inlet speeds and nozzle distance conditions were analyzed.The results show that under the same conditions,with the nozzle distance increasing,and the change trend of the number of collisions between the two particles increases and then decreases.It reaches the maximum when the ratio of the nozzle spacing to the nozzle diameter is 4 and the increasing in gas velocity has little effect on the number of particle collisions in the impact zone.