The much larger difference from the literature correlation may be due to the different definitions of jet penetration. Conclusions 1. In a two-dimensional fluidized bed with a circular jet there exists a maximum porosity region at a finite length above the jet inlet. This maximum increases with jet velocity. It occurs due to three-dimensional effects.2. In a two-dimensional bed with a rectangular jet of the same width as the fluidized bed, the time averaged void profiles are as they are expected to be from hydrodynamic calculations. Near the jet we have nearly elliptic profiles which then curve away from the center of the bed.3. Jet penetration depths can be determined from time-averaged porosity distributions. The actual length of jet penetration depends upon a particular definition adopted. This makes it difficult to compare the present data to various literature correlations that did not measure porosities. However, by use of the same definition, the jet penetrations for the circular and for the slit jets are very close to each other.

A hydrodynamic model of fluidization was developed that computes void fractions, pressure and solid and gas velocities in cylindrical fluidized beds. Cmputed time‐averaged gas velocity distributions of a jet compared well with Westinghouse experimental data without the use of any fitted parameters. The main empirical input was a drag correlation from the literature.

During the past three years we have developed a tentative cold bed hydrodynamic model [or an idealized fluidized bed gasifier. The computer program calculates the pressure, the void fraction and the velocities for a single size solid and [or a gas. The fluid bed never reaches a steady state, but continually oscillates, as bubbles [arm, rise through the bed and collapse on top of the bed.In this paper we show that the hydrodynamic model can predict bubbles [arming in the fluidized bed. Photographically determined bubble sizes agree with the predicted bubble sizes. They increase with height of bed and with jet velocity. The model produces bubble splitting which agrees with observations at higher jet velocities.

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