Phase diagrams, fluid-particle flow

Fluid-particle flow patterns are often clarified by application of phase diagrams. Kwauk (1963) and Matsen (1983) proposed such phase diagrams for moving beds. 

Fig. 22. Fluid-particle flow phase diagram for vertical moding bed (Li, 1991). 

Phase Diagram (Zenz and Othmer) Zenz and Othmer (op. cit.) have graphically represented (Fig. 17-2) all gas-solid svstems in which the gas is flowing counter to gravity as a function o pressure drop per unit of height versus velocity. Note that line OAB in Fig. 17-2 is the pressure-drop versus gas-velocity curve for a packed bed and BD the cui ve for a fluid bed. Zenz indicates an instability between D and H because with no sohds flow all the particles will be entrained from the bed however, if sohds are added to replace those entrained, system JJ prevails. The area DHJJ will be discussed further. 

FIG. 17-2 Schematic phase diagram in the region of upward gas flow. W = mass flow solids, lh/(h fr) E = fraction voids Pp = particle density, Ih/ft Py= fluid density, Ih/ft Cd = drag coefficient Re = modified Reynolds uum-her. (Zenz and Othmei Fluidization and Fluid Particle Systems, Reinhold, New York, 1960. )... 

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