Convective mass or heat transfer from size-distributed drops, bubbles or solid particles

Yaron, I.; Gal‐Or, Benjamin

doi:10.1016/0017-9310(71)90103-7

Cited by 37 publications

(5 citation statements)

References 24 publications

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“…It is difficult to estimate the drop velocity accurately in a turbulent environment. Furthermore, except for Ruckenstein's (1964) cellular model and Yaron and Gal-Or's (1971) extension to multiparticulate swarms, all the equations are restricted to single drops. The contribution of a single drop to overall mass transfer in an aggregate of drops is not well understood.…”

Section: (20)mentioning

confidence: 99%

Mass transfer in a liquid‐liquid CFSTR

Bapat

Tavlarides

1985

AIChE Journal

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The performance of a two-phase liquid-liquid continuous flow stirred tank reactor (CFSTR) was evaluated experimentally by simultaneous determination of dispersed phase drop size distribution and extraction efficiency as a function of reactor operating conditions. The results provided a basis against which predictions made by a previously developed simulation technique (Bapat et al., 1984) were compared. The close agreement between the experimental and the simulation results validates the drop rate models and the simulation algorithm employed in this work. P SCOPEMultiphase contacting is a commonly used operation in chemical process industries handling a wide range of substances in different forms and states of matter. Two-phase liquid-liquid contacting, which is a major multiphase operation, is frequently encountered in nuclear, hydrometallurgical, petrochemical, pharmaceutical, and food industries for extracting valuable substances. The optimum design and operation of such an extraction system require, in addition to the homogeneous reaction kinetics, a thorough understanding of the physical rate processes. The physical factors which influence the extractor performance are: (1) dispersed phase droplet processes (breakage and coalescence); (2) microscopic interphase transport processes; and (3) macroscopic flow patterns in the contacting equipment.The effect of these individual factors and their mutual interaction has not yet been quantitatively formulated by a comprehensive model. As a step in that direction, this work investigates the first two factors for a homogeneous liquid-liquid dispersion in a continuous flow stirred tank reactor (CFSTR). The dynamics of the dispersed phase drop interactions and the microscopic interphase mass transfer in the turbulent flow field were simulated to predict the behavior of the liquid extractor. The predictions are validated by comparison against the experimental data acquired from a cyclohexane/carbontetrachloride(dHiodine]-water(c) dispersion agitated in a one-liter CFSTR system capable of providing simultaneous determination of drop size distribution and extraction efficiency. The drop size distributions are obtained by in situ photomicrography. The mass transfer efficiencies are estimated by spectrophotometric iodine concentration measurements of the reactor dispersion phases separated by a specially developed instantaneous in situ membrane filtration technique.In the past, the population balance equation (PBE) that provides the mathematical apparatus for describing the particulate systems has been used successfully to obtain the dispersion state distributions ( Simulation of interphase transport in two-phase liquid-liquid dispersions has not been successfully attempted before the present work. The highly interactive droplet swarm in a turbulent environment has precluded any theoretical treatment of these processes. Experimental estimation of interphase mass transfer also encounters major difficulties due to turbulence in mechanically agitated stirred tanks. Because the...

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Section: (20)mentioning

confidence: 99%

Mass transfer in a liquid‐liquid CFSTR

Bapat

Tavlarides

1985

AIChE Journal

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“…nature of the outer boundary and its radius, the latter depending upon the mucus-solids content. Cell models akin to the one proposed here have been used to accurately model convection plus diffusion in particulate systems (Yaron and Gal-Or, 1971) as well as diffusion alone within bovine cervical mucus (Katz and Singer, 1978). The core of each cell is occupied by cylindrical filaments.…”

Section: Theoretical Modelmentioning

confidence: 99%

Flow permeation analysis of bovine cervical mucus

Katz¹,

Tam²,

Berger³

et al. 1982

Biophysical Journal

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Geometrical properties of the microstructure of whole bovine cervical mucus were studied. An experimental technique was developed for measuring the flow of fluid through the mucus microstructure in response to application or a prescribed external pressure gradient. The data obtained were analyzed in conjunction with a mathematical model of the hydrodynamics of the flow-permeation process. The sizes of typical interstices within the microstructure were calculated to be of the order of 1 micrometer, with typical macromolecular filament diameters being of the order of 100 A. These dimensions were interpreted as representative of an equivalent network giving rise to measured flow permeability. The values of filament size showed a strong experimental correlation with the solids content of the mucus.

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“…The flow is assumed to be axisymmetric. Under these conditions, for a thin boundary layer (Pe = 2 a u / D~ >> I), the In the absence of a chemical reaction, Equation (5) has been shown (Ruckenstein, 1964; Yaron and Gal-Or, 1971) to represent well the concentration profile within the boundary layer, Also, in the case of a first-order irreversible reaction, Equation (5) allows predictions of Sherwood numbers well in agreement with the ones obtained from well-known penetration theory (Shah, 1972). Because of these results, Equation ( The results of Sherwood number obtained here applies to the case of a single bubble when @ + 0.…”

Section: Theorymentioning

confidence: 99%

Simultaneous mass transfer and equilibrium chemical reaction from moving bubbles: Film theory

Shah

1972

AIChE Journal

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Convective mass or heat transfer from size-distributed drops, bubbles or solid particles

Cited by 37 publications

References 24 publications

Mass transfer in a liquid‐liquid CFSTR

Mass transfer in a liquid‐liquid CFSTR

Flow permeation analysis of bovine cervical mucus

Simultaneous mass transfer and equilibrium chemical reaction from moving bubbles: Film theory

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