新颖环形喷动床颗粒喷动特性实验研究

一种新颖的环形喷动床由内外两个不同内径、同心的垂立圆筒组成,在环形空间底部设置多个喷口,在喷口两侧布置倾斜的导流板.研究颗粒在这种喷动床内的流动特性,探讨喷口结构、颗粒种类以及床内载料量对环形喷动床颗粒喷动特性的影响.实验结果表明:颗粒在环形喷动床内分为三个明显不同的区域,即颗粒填充移动区、密相喷动流化区以及稀相夹带区.当颗粒出现分区喷动后,随床内载料量的增多,填充移动区的高度维持不变,始终等于导流板的高度,而密相喷动区的高度不断增加.风量和颗粒种类对床层最大喷动量、密相喷动高度以及床层压力分布规律有着十分重要的影响.采用不同的喷口结构时,在相同的载料量下,直向喷口的密相喷动区高度更大,而且床内各测点的平均压力大于采用斜向喷口时的相应测点压力.

Experimental Study on Particles Spouting Characteristics in a Novel Annular Spouted Bed

A novel annular spouted bed was developed, which was consisted of two concentric hollow cylinders with different diameters, and several nozzles with guide plates were symmetrically arranged on the bottom of the annular space between the two hollow cylinders. Experiments were conducted to study the particles spouting characteristics in the novel spouted bed, then the effects of nozzle structure, kinds of tested particles and the added amount of tested particles on the spouted fluidizing behaviors of tested particles in the annular spouted bed were discussed. The results show that the particles flow in the annular spouted bed commonly can be divided into three different zones, namely the moving packed zone, the dense-phase spouted fluidizing zone and the dilute-phase zone. Once the three different particles flow zones were established, the height of the moving packed zone will keep unchanged and will always equal to the height of the guide plates, while the height of the dense-phase spouted fluidizing zone will increase with the increase of the added amount of tested particles. It was also found that the spouting gas velocity and the difference of tested particles have important influences on the maximum spouting amount of particles, the height of dense-phase spouted fluidizing zone and the bed pressure fluctuation. Under the same spouting condition, the height of dense-phase spouted fluidizing zone and the bed pressure caused by forward nozzles is higher than those caused by angled nozzles.