BUBBLE-CHORD LENGTH AND PRESSURE-FLUCTUATIONS IN 3-PHASE FLUIDIZED-BEDS

Abstract

The bubble-chord lengths, l(V)'s, and pressure fluctuations were measured in three-phase fluidized beds by focusing on the effects of gas flow rate, liquid flow rate, and particle size on them. The pressure fluctuations have been analyzed by resorting to fractal analysis. Specifically, the rescaled range analysis has been applied to time series of the pressure fluctuations, thus giving rise to the Hurst exponent, H. It has been revealed that as the gas flow rate in a bed increases, l(V) and the standard deviation of its distribution increase but H decreases, and that the opposite is true as the liquid flow rate increases. The Hurst exponent, H, has been correlated in terms of the operational variables and the geometrical features of the beds, and l(V) has been correlated as a function of H and the radial position in the bed.