FLOW PATTERNS AROUND AND INSIDE A BUBBLE IN A GAS-FLUIDIZED BED

A theoretical analysis presented for the gas flow around and inside bubbles in fluidised beds. Spherical or cylindrical bubbles are considered, as well as steady or unsteady bubble motion. Particular attention was given to the unsteady behaviour of cylindrical and spherical bubble clouds. The effect of bubble velocity variation on the cloud penetration is discussed using the theory of Collins. An analytical solution is presented for the gas flow inside an cylindrical bubble that matches Davidson's description of the gas flow outside the bubble. The flow inside a growing bubble is qualitatively suggested based on the preceding theories. © 1990.