The gassolid two-phase flow in the standpipe is characteristic of the flowing against negative pressure and slip velocity upward, which made flow instability of the gassolid two-phase flow.

• 另一种是流量振荡；流量在一定的范围内发生波动变化；即低频脉动流动；这是颗粒逆压力梯度流动压缩气体造成的.；负压差立管气固流动的不稳定性对工艺过程的运行具有潜在的危害性