Hydrodynamic model of interfacial area for trickling flow in a packed bed

Abstract

To predict local interfacial area in a packed bed under the trickling flow, a wavy annular flow model was developed by introducing the shape of waves in a thin liquid film. The trickling flowin a packed bed was approximated by an annular flow through a number of equivalent channels in which the continuous gas and liquid were completely separated by a wavy interface. Film thicknesses were measured by parallel wire probes to estimate the wave structure on the interface. By integrating the interfacial areas over a certain time period, the time-averaged local interfacial area was evaluated from a low to high interaction flow regime: 1) from trickling to bubbly flow and 2) from trickling to pulsing flow. The interfacial area predicted by the wavy annular flow model in the trickling flow was moderately higher than those predicted with the empirical correlations developed by others. The results show that the interfacial area increases more significantly as the flow regime changes from trickling to pulsing flow than that increases as the flow regime changes from trickling to bubbly flow. As a result, the wave structure on the interface should be considered to predict more accurate interfacial area in a packed bed.