Industrial & Engineering Chemistry Research, Vol.44, No.25, 9446-9450, 2005
Characterization of multiple flow morphologies within the trickle flow regime
The existence of multiple hydrodynamic states in the trickle flow regime is a well documented, but as yet poorly quantified phenomenon. The prewetting procedure is known to drastically impact the hydrodynamic state and morphology of the liquid flow. In this work, three limiting cases for the case of no gas flow are identified: Nonprewetted, Levec-prewetted, and pseudo-Kan-prewetted. For the quiescent air-distilled water-3 mm glass spheres system, it is shown that bed-scale maldistribution exists in all three modes of operation, but is more severe in the Levec- and nonprewetted modes. The incorporation of a novel volumetric utilization coefficient into an existing momentum balance-based holdup model is sufficient to accurately model the holdup in all prewetted modes (AARE = 9.2%). This results in the first holdup model that takes the prewetting procedure into account. Present results support the notion that Kan-type prewetting results in film flow, while Levec- and nonprewetted modes are dominated by rivulet flow.