Study of turbulent flow in a porous tube with high mass flux to and from the wall
30 Dec 1972-Journal of Chemical Engineering of Japan (The Society of Chemical Engineers, Japan)-Vol. 5, Iss: 4, pp 361-364
TL;DR: In this paper, a fully developed turbulent flow of an electrolyte solution in a porous-wall tube with suction or injection flow through the wall was experimentally studied and the measurements of mass transfer rates at the wall were made by an electrochemical method.
Abstract: A fully developed turbulent flow of an electrolyte solution in a porous-wall tube with suction or injection flow through the wall was experimentally studied. The measurements of mass transfer rates at the wall were made by an electrochemical method. Reynolds number were varied from 7900 to 21, 000 and Schmidt numbers were 750, 1100, 1920 and 2100. The mass flow ratios ρvw/ρU ranged from -2.13×10-5 to 5.59×10-5. It was recognized that mass transfer coefficients at the wall rise with increase of suction rate and fall with increase of injection rate. The results are in good agreement with predictions by film theory.
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TL;DR: In this article, a critical review on the mass transfer correlations under turbulent duct flow, as they appeared in the literature ( 1934-1984), and a discussion on the factors influencing mass transfer during membrane operations (reverse osmosis and ultrafiltration), like porosity and roughness of the membrane wall and change of viscosity and diffusion coefficient due to the strong concentration gradient.
358 citations
TL;DR: In this paper, high-Schmidt-number mass transfer in the concentration polarization boundary layer during ultrafiltration (UF) was studied. Butts et al. used a simulation program based on a control volume formulation.
37 citations
TL;DR: In this article, the authors investigated the use of fluidised beds as turbulence promotors in tubular membrane systems and found that mass transfer is favourably effected at superficial velocities as low as 1 cm/sec.
36 citations
TL;DR: The turbulent Schmidt number relationship is derived from spatially resolved measurements of the Reynolds stress and measurements of mass transfer coefficients for high Schmidt number solutes as discussed by the authors, and it has also been proven to be capable of handling cases where suction at the wall takes place.
Abstract: Results of computer simulations using a low Reynolds number k—ϵ model by Chien combined with the derived turbulent Schmidt number relationship reveal a good agreement with experimental results over a broad Schmidt and Reynolds number range. The turbulent Schmidt number relationship is derived from spatially resolved measurements of the Reynolds stress −ϱ l u ′ v ′ and measurements of mass transfer coefficients for high Schmidt number solutes. The computational fluid dynamic approach for the prediction of turbulent high Schmidt number mass transfer would thus also serve as the basis for a tool in cases where the molecular properties such as diffusivity and change in the vicinity of the wall which conventional mass transfer relationships are unable to in a general way. It has also been proven to be capable of handling cases where suction at the wall takes place.
20 citations
01 Oct 1977
TL;DR: In this article, specific solute/membrane interactions between an anionic surfactant (sodium dodecyl sulfate, SDS) as a solute and different membranes were investigated by comparing results from ultrafiltration experiments with uncharged polyacrylonitrile membranes, with results from hyperfiltration experiment with cation exchange membranes.
Abstract: Specific solute/membrane interactions have been studied between an anionic surfactant (sodium dodecyl sulfate, SDS) as a solute and different membranes. Specific interactions between SDS and cation exchange membranes were investigated by comparing results from ultrafiltration experiments with uncharged polyacrylonitrile membranes, with results from hyperfiltration experiments with cation exchange membranes. The first experiments showed a remarkable difference in the dependance of flux and rejection on the concentration SDS below and above the critical micelle concentration (CMC). This difference is due to the formation of micelles in the solution above the CMC and offers the possibility of calculating mass transfer coefficients for the SDS micelles. Experiments with cation exchange membranes have already shown an increase in rejection far below the CMC, which also could be ascribed to micelle formation. It is concluded that the formation of micelles below the bulk CMC can start, since the ionic groups in the membrane act like an indifferent electrolyte lowering the CMC at the interface. Concentration polarization moduli and mass transfer coefficients were calculated by plotting the rejection and flux against the logarithm of the surfactant concentration. The experimental results proved to be in fair agreement with the theoretical values.
7 citations