Hydrodynamics of large jetting fluidized bed

Voidage distribution along radial and axial directions in a cold flow semic ircular fluidized bed 500 mm in diameter and 8000 mm in height was measured with a PC-4 optic fiber probe. The radial voidage profile is divided into jet and emulsion phase regions. The radial voidage profile in the jet regio n has an elliptic contour, but the voidage in the emulsion phase region is found to be equal to that under minimum fluidizating conditions. An empiric al correlation for predicting the jet region voidage is proposed. The time series of pressure fluctuation are analyzed by deterministic chaos theory a nd power spectrum density function, and effects of jet gas velocity and sta tic bed height on the correlation dimension and on major frequency are inve stigated. It is found that the major frequency (jet collapse frequency) inc reases with jet gas velocity. The results show that the correlation dimensi on increases with jet gas velocity. For a given jet gas velocity, the highe r the static bed height, the greater the correlation dimension.