Hydrodynamics of the cocurrent downflow of a gas and a foaming liquid through a packed bed. Part I. Estimation of the transition boundary between the hydrodynamic regimes from the gas continuous flow to the pulsing flow

In the study the results of investigations are presented aimed at determining such values of the operating parameters for which the change of the hydrodynamic regime occurs from the gas continuous flow (GCF) to the pulsing flow (PF). Nitrogen, helium and argon were used as the gas phase while the liquid phase was formed by the aqueous solutions of the alcohols C1–C4 of the concentrations which ensured the foaming of the system. Thus a wide range of physicochemical properties of the system was covered in the experiments. The present study, as well as Part II, contain a wealth of experimental data which characterise the PF through the packing for the foam-forming systems. It is demonstrated that none of the published mathematical criteria based on the models of the flow describes the transition line between the hydrodynamic regimes (from GCF to PF) with sufficient accuracy. For these types of systems the use of the modified flow map (Fig. 4) is advised or, alternatively, of the equation describing the boundary line between GCF and PF in the following form: Lλψ0.548/G=3.12(G/λ)−1.16.