RAPID CHARACTERIZATION OF FLOW REGIMES IN MULTIPHASE REACTORS THROUGHBOX-COUNTING DIMENSIONS WITH AN EMBEDDING DIMENSION OF 2

The performance of multiphase reactors is greatly affected by their Bo w regime. The box-counting dimension of a probe signal characterizes i ts intrinsic, dimensionless structure and is not significantly affecte d by moderate changes in probe calibration constants. Using the box-co unting dimension to characterize the flow regime can, thus, eliminate problems associated with changes in probe, liquid or solid characteris tics. This study uses an approximate box-counting dimension which is s o rapidly calculated that it could be used for on-line control. The bo x-counting dimension of the raw signal from a bubble probe allows the accurate detection of gas maldistribution in bubble columns and gas-li quid-solid fluidized beds. The box-counting dimension of the raw signa l from a local conductivity probe allows the accurate detection of liq uid maldistribution in bubble columns and gas-liquid-solid fluidized b eds. The fluidization regime of liquid-solid and gas-liquid-solid beds can be accurately identified from the box-counting dimension of the s ignal recorded with either local probes or cross-sectional probes. The complete fluidization of a liquid-solid bed of splinter-like particle s can be determined from the box-counting dimension of the signals fro m either a local probe or tracer injection experiments.