格栅型煤粉分配器的分配特性研究

Research on the distribution characteristics of grille-type pulverized coal distributor

为了研究格栅型煤粉分配器的均匀分配效果,在分配器入口前加设一段弯管以形成分配器入口气固两相流动的非均匀条件,利用Fluent软件对不同格栅数的煤粉分配器的性能进行数值模拟,得到其内部流动情况以及颗粒运动状态。结果表明:在两级格栅出口转角处磨损严重,在流通截面扩大处磨损较小;每根支管的出口速度都不均匀。随着格栅数增加,各出粉支管之间的流动偏差减小,8格栅时偏差最小,同时也能够满足送粉工况对煤粉分配器初始分配均匀性的要求。颗粒的运动在“主流区”内跟随性好,而在“主流区”外运动较随机;格栅出流方向的不同顺序对流动偏差影响不大。另外,煤粉分配器的进口风粉分布和出口送粉管道的阻力特性会对分配器的初始分配效果产生不同程度的影响。

In order to get the distribution characteristics in the grille-type pulverized coal distributor,an elbow was equipped in the front of the distributor to create an uneven gas-solid twophase flow.The numerical simulation of pulverized coal distributor with different grilles was performed via Fluent software to get the flow and motion state of the particles in the distributor.The results show that severe abrasion is observed at the corner of 2 grilles while less abrasion occurs at the expansion section.The outlet velocity of each grille branch is uneven.With the increase of the grille number,the flow deviation between each branch decreases.And the least deviation is achieved for 8 grilles,which can meet the requirements of the initial distribution uniformity in the pulverized coal distributor.The particles in the mainstream area have good following performance while the particle motion out of the mainstream is random.The different flow directions of the grilles have little effect on the flow deviation.In addition,both the inlet air distribution and the resistance in the outlet of pulverized coal blast pipes have different effects on the initial distribution performance of the distributor.