An experimental study on the liquid phase properties of a bubble column operated in the homogeneous and in the heterogeneous regimes

We present an experimental study on the liquid phase properties in a bubble column. The reactor, that has a diameter of 40 cm, can be operated in both the homogeneous and the heterogeneous regimes, reaching superficial gas velocities and void fractions up to 23.2 cm/s and 30%, respectively.Our measurements, obtained with a Pavlov tube, have a temporal resolution of 20 Hz, and cover differ-ent superficial gas velocities and axial and radial positions. The moderate temporal resolution achieved allowed to quantify the liquid velocity via probability density functions, standard deviations, spectra and spatial and temporal integral scales.Spectral analysis was performed to study the validity of bubble-induced turbulence models. While such models were developed for the homogeneous regime, we show that they can be applied, with some lim-itations, to the heterogeneous one. In particular, a-3 power law is found in the liquid velocity spectra, with integral scales related to the column's diameter.(c) 2022 Elsevier Ltd. All rights reserved.