Rapid characterization of flow regimes in multiphase reactors through box-counting dimensions with an embedding dimension of two

Abstract

The performance of multiphase reactors is greatly affected by their flow regime. The box-counting dimension of a probe signal characterizes its intrinsic, dimensionless structure and is not significantly affected by moderate changes in probe calibration constants. Using the box-counting dimension to characterize the flow regime can, thus, eliminate problems associated with changes in probe, liquid or solid characteristics. This study uses an approximate box-counting dimension which is so rapidly calculated that it could be used for on-line control. The box-counting dimension of the raw signal from a bubble probe allows the accurate detection of gas maldistribution in bubble columns and gas-liquid-solid fluidized beds. The box-counting dimension of the raw signal from a local conductivity probe allows the accurate detection of liquid maldistribution in bubble columns and gas-liquid-solid fluidized beds. The fluidization regime of liquid-solid and gas-liquid-solid beds can be accurately identified from the box-counting dimension of the signal recorded with either local probes or cross-sectional probes. The complete fluidization of a liquid-solid bed of splinter-like particles can be determined from the box-counting dimension of the signals from either a local probe or trace rinjection experiments.