竖直槽道中稠密气粒两相流动的瞬态结构

EXPERIMENTAL STUDIES ON TRANSIENT STRUCTURES OF DENSE GAS-SOLID FLOWS IN A VERTICAL CHANNEL

本文采用流动显示方法对竖直槽道中稠密气粒两相流动的瞬态结构进行了研究,发现当表观气速高于管道流态化的最小临界速度但低于节涌状态向湍动状态过渡的临界速度时,槽道中没有明显的气泡出现,而是形成一条穿过颗粒密相区的气流通道。当表观气速较低时,气流通道始终偏向槽道一侧。表现气速较高时,气流通道在槽道两侧摆动。在湍动状态下,槽道中的流态和管道中的流态相似。在快速流态化情况下,当颗粒循环量在一定范围时,槽道壁面附近会出现准静止的大尺度颗粒团。

Upward gas-solid flows were studied by visualization. It is found that a gas flow tunnel through particle dense phase instead of bubbles forms in the channel when superficial gas velocity is higher than minimum fluidization velocity and lower than the critical velocity at which slugging fluidization changes to turbulent fluidization. The flow structure in the channel is similar as that in the pipes when the superficial gas velocity is high. Under a certain operational condition, the large scale clusters similar as the dune can be observed in the region near the wall.