2015 Volume 52 Issue 8 Pages 453-461
When a cohesive powder classified into Group A and C particles of Geldart's classification is discharged from an orifice on a vessel, a cohesive arch or bridging is formed and the discharge is blocked. On the other hand, in some operating conditions, the cohesive powder is suddenly discharged from a narrow gap with the relatively high mass flow rate. This phenomenon is called "flushing". The bridging and the flushing cause troubles in the powder handling device, these phenomena should be avoided. In order to avoid these troubles, the understanding of the flow properties of the cohesive powder with air flow is greatly important. In this review, the flushing phenomenon from a vessel by supplying air pressure is focused. The location of the air supply is classified into three locations, which are the top, the bottom and both sides. In each case, the effect of the void fraction and the interstitial pressure on the discharge of the cohesive powder is explained.
