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Liquid Film Flow (liquid + film_flow)

Distribution by Scientific Domains
Chemistry100%

Selected Abstracts

CFD Simulation of Liquid Film Flow on Inclined Plates

CHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 10 2004
F. Gu
Abstract A two-phase flow CFD model using the volume of fluid (VOF) method is presented for predicting the hydrodynamics of falling film flow on inclined plates, corresponding to the surface texture of structured packing. Using the proposed CFD model the influence of the solid surface microstructure, liquid properties and gas flow rate on the flow behavior was investigated. From the simulated results it was shown that under the condition of no gas flow the liquid flow patterns are dependent on the microstructure of the plates, and proper microstructuring of the solid surface will improve the formation of a continuous liquid film. It was also found that liquid properties, especially surface tension, play an important role in determining the thin-film pattern. However, there are very different liquid film patterns under the action of gas flow. Thinner liquid films break easily, but thicker liquid films can remain continuous even at higher gas flow rates, which demonstrates that all factors affecting the liquid film thickness will affect the liquid film patterns under conditions of counter-current two-phase flow. [source]

Hydrodynamics and mass transfer of gas,liquid flow in a falling film microreactor

AICHE JOURNAL, Issue 5 2009
Haocui Zhang
Abstract In this article, flow pattern of liquid film and flooding phenomena of a falling film microreactor (FFMR) were investigated using high-speed CCD camera. Three flow regimes were identified as "corner rivulet flow," "falling film flow with dry patches," and "complete falling film flow" when liquid flow rate increased gradually. Besides liquid film flow in microchannels, a flooding presented as the flow of liquid along the side wall of gas chamber in FFMR was found at high liquid flow rate. Moreover, the flooding could be initiated at lower flow rate with the reduction of the depth of the gas chamber. CO2 absorption was then investigated under the complete falling flow regime in FFMR, where the effects of liquid viscosity and surface tension on mass transfer were demonstrated. The experimental results indicate that kL is in the range of 5.83 to 13.4 × 10,5 m s,1 and an empirical correlation was proposed to predict kL in FFMR. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Two-phase flow in structured packings: Modeling and calculation on a macroscopic scale

AICHE JOURNAL, Issue 3 2008
B. Mahr
Abstract A model is presented that allows calculating the macroscopic flow field of counter-current two-phase flow in strongly anisotropic porous structures. It is applied to corrugated structured packings. All flow field variables and packing properties are averaged over the volume of an elementary cell. The anisotropic gas flow resistance is derived from measurements and from separate CFD calculations on 3D-X-ray CT scans. The liquid's flow resistance is calculated using an analytical model of liquid film flow on an inclined plate. Liquid flow along both preferential flow directions is represented by two separate phases, in order to consider horizontal forces despite their symmetry. Gas-liquid momentum transfer above the loading point is included. The macroscopic flow field is calculated for a 288 mm I.D. column containing four packing elements. Liquid spreading from a point source, for uniform irrigation, increased hold-up at the packing elements' joints and pressure drop are tested against experimental results. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source]

Mathematical Modelling of Non-Isothermal Venturi Scrubbers

THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2005
Amir Rahimi
Abstract A mathematical model consisting of differential equations for energy, momentum and material exchange is developed for a non-isothermal Venturi-type scrubber. By this model, the effects of heat and mass transfer on droplets concentration distribution and removal efficiency of particulate in a non-isothermal Venturi scrubber can be investigated. In order to approach a realistic model, the liquid film flow on the walls and droplet size distribution are considered. The model is validated by comparing the results of mathematical model by plant and experimental data reported in the literature. The Results section of this work reveals that the inlet humidity and temperature of the gas can affect the removal efficiency of the scrubber. On a mis au point un modèle d'équations différentielles pour l'échange d'énergie, de quantité de mouvement et de matière pour un épurateur venturi non isotherme. Grâce à ce modèle, on peut étudier les effets du transfert de chaleur et de matière sur la distribution de concentration des gouttelettes et l'efficacité de retrait des particules dans un épurateur venturi non isotherme. Pour s'approcher le plus possible d'un modèle réaliste, l'écoulement liquide sur les parois et la distribution de taille des gouttelettes sont considérés. Le modèle est validé en comparant les résultats du modèle mathématique à des données expérimentales parues dans la littérature scientifique et des données d'usine. Les résultats de ce travail révèlent que l'humidité et la température de gaz à l'entrée peuvent influer sur l'efficacité de retrait de l'épurateur. [source]