Fluidization Behaviors of Gas-Solid Two-phase Flow in the Standpipe under Negative Pressure Gradient
负压差立管内气固两相流的流态特性及分析

Fluidization behaviors of gassolid two-phase flow were studied based on experiments in a f150 mm11500 mm standpipe under negative pressure gradient. The standpipe exit was dipped into a dense fluidization bed. The gassolid two-phase flow in the standpipe is characteristic of flowing against negative pressure and slip velocity upward. The fluidization behaviors of the gassolid flow in the standpipe are effected by mass flux of solid. When the mass flux of solid is less than 200~250 kg/(m2.s), there are two fluidization regimes coexisting in the standpipe, i.e., the upper dilute-phase flow and bottom dense-phase flow with gas flowing upward. When the mass flux of solid is more than 200~250 kg/(m2.s), there is only one dense-phase conveying regime in the standpipe with gas flowing downward. The particles flowing down is a decelerate process in the standpipe and the slip velocity decreases as mass flux of solid increases.