基于CFD-DEM耦合模拟的侧喷吹管道减磨弯头流动特性分析

Study on the flow characteristics of wear-resistant elbow in side injection pipeline by CFD-DEM coupled simulation

为实现煤粉颗粒在管道和喷枪内的稳定可靠输送和精确喷吹,以气固两相物料在弯头内的流动特性为对象,采用计算流体力学与离散元耦合(CFD-DEM)方法对普通弯头、T型弯头、堵塞型弯头、球型弯头内颗粒运动情况进行分析,研究发现:颗粒流经三种减磨弯头时速度会出现显著的下降,同时还会引起显著气流速度和压强的波动,上述现象以T型弯头最为显著;减磨弯头通过颗粒床中颗粒-颗粒碰撞减小颗粒对管壁的冲击,三种减磨弯头中颗粒-颗粒碰撞次数与碰撞法向力均较高,可能引发喷吹物料流动的紊乱。

The flow characteristics of gas-solid two-phase flow in elbows are numerical simulated by computational fluid dynamics and discrete element coupling method(CFD-DEM).The aforementioned flow characteristics are important factors to ensure stable and reliable transportation of side injection for coal powder particles in nonferrous metal smelting.The ordinary elbows,the T-shaped elbows,the blind elbows,and spherical elbows are selected to discuss.The results show that there is significant velocity decrease in the three wear-resistant elbows.Meanwhile,significant fluctuations in airflow velocity and pressure are also found in the wear-resistant elbows,which is most significant in the T-shaped elbows.It is also found that the wear-resistant elbow can reduces the wall erosion by particle-particle collisions rather than particle-wall collisions.The number of particle to particle collisions and the contact normal force are relatively high in the three types of wearresistant elbow,which is a potential factor to flow turbulence in sprayed processing.