Dissertations / Theses on the topic 'Transporting gas or liquid'
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1
Aldred, Matthew P. "Charge-transporting and electroluminescent liquid crystals for organic light-emitting diodes." Thesis, University of Hull, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.415806.
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Jean, Rong-Her. "Hydrodynamics and gas-liquid mass transfer in liquid-solid and gas-liquid-solid fluidized beds /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487596807822292.
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Odozi, Utomi Ayodele. "Three-phase gas/liquid/liquid slug flow." Thesis, Imperial College London, 2000. http://hdl.handle.net/10044/1/8444.
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Zidan, M. D. "Gas-liquid surface interactions." Thesis, University of Sussex, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333478.
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Song, Gyung-Ho. "Hydrodynamics and interfacial gas-liquid mass transfer of gas-liquid-solid fluidized beds /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487599963590971.
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Lei, Pan. "High pressure three-phase (gas/liquid/liquid) flow." Thesis, Imperial College London, 1996. http://hdl.handle.net/10044/1/7204.
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Singh, Jaswant. "Gas entrainment by liquid sprays." Thesis, University of Leeds, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432173.
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Jensen, Anne-Lise B. "Models of gas-liquid solubilities." Thesis, Aston University, 1996. http://publications.aston.ac.uk/9616/.
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A recent method for phase equilibria, the AGAPE method, has been used to predict activity coefficients and excess Gibbs energy for binary mixtures with good accuracy. The theory, based on a generalised London potential (GLP), accounts for intermolecular attractive forces. Unlike existing prediction methods, for example UNIFAC, the AGAPE method uses only information derived from accessible experimental data and molecular information for pure components. Presently, the AGAPE method has some limitations, namely that the mixtures must consist of small, non-polar compounds with no hydrogen bonding, at low moderate pressures and at conditions below the critical conditions of the components. Distinction between vapour-liquid equilibria and gas-liquid solubility is rather arbitrary and it seems reasonable to extend these ideas to solubility. The AGAPE model uses a molecular lattice-based mixing rule. By judicious use of computer programs a methodology was created to examine a body of experimental gas-liquid solubility data for gases such as carbon dioxide, propane, n-butane or sulphur hexafluoride which all have critical temperatures a little above 298 K dissolved in benzene, cyclo-hexane and methanol. Within this methodology the value of the GLP as an ab initio combining rule for such solutes in very dilute solutions in a variety of liquids has been tested. Using the GLP as a mixing rule involves the computation of rotationally averaged interactions between the constituent atoms, and new calculations have had to be made to discover the magnitude of the unlike pair interactions. These numbers have been seen as significant in their own right in the context of the behaviour of infinitely-dilute solutions. A method for extending this treatment to "permanent" gases has also been developed. The findings from the GLP method and from the more general AGAPE approach have been examined in the context of other models for gas-liquid solubility, both "classical" and contemporary, in particular those derived from equations-of-state methods and from reference solvent methods.
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Khor, Siew Hiang. "Three-phase liquid-liquid-gas stratified flow in pipelines." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/8714.
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Pan, Jin. "Gas Entrainment in Two-Phase Gas-Liquid Slug Flow." Thesis, Imperial College London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516177.
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Lau, Wai Man. "Hydrodynamics and mass transfer studies in high pressure gas-liquid and gas-liquid-solid fluidization." The Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1070295869.
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Lau, Wai Man R. "Hydrodynamics and mass transfer studies in high pressure gas-liquid and gas-liquid-solid fluidization." Connect to this title online, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1070295869.
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Thesis (Ph. D.)--Ohio State University, 2003.Title from first page of PDF file. Document formatted into pages; contains xix, 168 p.; also includes graphics (some col.) Includes bibliographical references (p. 159-168). Available online via OhioLINK's ETD Center
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Ritu, Ritu. "Experimental investigations of mass transfer kinetics in liquid/liquid and liquid/gas systems." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0315.
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Cette thèse de doctorat présente des résultats expérimentaux sur le transfert de masse dans des systèmes impliquant des interfaces liquide/liquide et liquide/gaz et se concentre sur leur cinétique lors de variations de conditions de composition et de thermodynamique. L'étude se concentre d'abord sur les systèmes liquide/liquide où les propriétés des interfaces eau-huile sont modifiées avec les tensioactifs. Le montage expérimental consiste en gouttes aqueuses pendantes immergées dans un mélange d’huile de paraffine (PO) et de Span 80. Au fil du temps, l’interface eau/PO devient opaque en raison de la formation de microstructures résultant de l’émulsification spontanée. À faible concentration, l'évolution dans le temps est lente et des gouttelettes de la taille d'un micromètre sont formées, tandis que pour de fortes concentrations, il est rapide et l'on observe des microstructures en forme de buisson. Il est prouvé que le taux d'émulsification spontanée augmente à haute température et en présence de tensioactifs hydrosolubles. Les propriétés des interfaces liquide/liquide sont également étudiées avec la spectroscopie par imagerie FTIR. Le transport de l'eau dans la phase CCl4 est mis en évidence et sa cinétique étudiée à la température ambiante pour plusieurs concentrations de Span 80. Les flux de masse à travers les interfaces liquide/gaz sont finalement étudiés avec la spectroscopie par imagerie FTIR. La cinétique d’évaporation des liquides utilisés dans le projet MAP “Evaporation Patterns” de l’Agence spatiale européenne est enfin étudiée. Les profils de concentration de vapeur sont mesurés pour HFE et le mélange de HFE et d'éthanol dans des conditions standardThis doctoral thesis presents experimental results on mass transfer in systems involving liquid/liquid and liquid/gas interfaces and focuses on their kinetics when varying composition and thermodynamics conditions. The study first concentrates on liquid/liquid systems where the properties of water-oil interfaces are modified with surfactants. Experimental setup consists in pendant aqueous drops immersed in a mixture of paraffin oil (PO) and Span 80. As time runs, the water/PO interface turns opaque due to the formation of microstructures as a result of spontaneous emulsification. At low concentrations, time evolution is slow, and micrometer sized droplets are formed whereas for high concentrations, it is fast and bush-like microstructures are observed. It is evidenced that the rate of spontaneous emulsification increases at high temperatures and in the presence of water-soluble surfactants. Properties of liquid/liquid interfaces are further investigated with FTIR imaging spectroscopy. Water transport into the CCl4 phase is evidenced and its kinetics investigated at room temperature for several Span 80 concentrations. FTIR imaging allows access to spatial distribution of water and thus, evolution of concentration profiles was measured. Mass flows across liquid/gas interfaces are finally investigated with FTIR imaging spectroscopy. Evaporation kinetics of liquids used in the “Evaporation Patterns” MAP project of the European Space Agency is finally studied. The vapor concentration profiles are measured for hydrofluoroether (HFE) and mixture of HFE and ethanol in standard conditions. The flow profiles as well as average evaporation rates are measured
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Shahrokhi, Habibullah. "Fine drop recovery in batch gas-agitated liquid-liquid systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0022/NQ35319.pdf.
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Manolis, Ionnis Georgios. "High pressure gas-liquid slug flow." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633654.
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Moore, Bryce Kirk. "Gas-liquid flows in adsorbent microchannels." Thesis, Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47519.
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A study of two the sequential displacement of gas and liquid phases in microchannels for eventual application in temperature swing adsorption (TSA) methane purification systems was performed. A model for bulk fluid displacement in 200 m channels was developed and validated using data from an air-water flow visualization study performed on glass microchannel test sections with a hydraulic diameter of 203 m. High-speed video recording was used to observe displacement samples at two separate channel locations for both the displacement of gas by liquid and liquid by gas, and for driving pressure gradients ranging from 19 to 450 kPa m-1. Interface velocities, void fractions, and film thicknesses were determined using image analysis software for each of the 63 sample videos obtained.
Coupled 2-D heat and mass transfer models were developed to simulate a TSA gas separation process in which impurities in the gas supply were removed through adsorption into adsorbent coated microchannel walls. These models were used to evaluate the impact of residual liquid films on system mass transfer during the adsorption process. It was determined that for a TSA methane purification system to be effective, it is necessary to purge liquid from the adsorbent channel. This intermediate purge phase will benefit the mass transfer performance of the adsorption system by removing significant amounts of residual liquid from the channel and by causing the onset of rivulet flow in the channel. The existence of the remaining dry wall area, which is characteristic of the rivulet flow regime, improves system mass transfer performance in the presence of residual liquid.
The commercial viability of microchannel TSA gas separation systems depends strongly on the ability to mitigate the presence and effects of residual liquid in the adsorbent channels. While the use of liquid heat transfer fluids in the microchannel structure provides rapid heating and cooling of the adsorbent mass, the management of residual liquid remains a significant hurdle. In addition, such systems will require reliable prevention of interaction between the adsorbent and the liquid heat transfer fluid, whether through the development and fabrication of highly selective polymer matrix materials or the use of non-interacting large-molecule liquid heat transfer fluids. If these hurdles can be successfully addressed, microchannel TSA systems may have the potential to become a competitive technology in large-scale gas separation.
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Badie, Shahrokh. "Horizontal stratifying annular gas liquid flow." Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249385.
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Barhey, Avtar Singh. "Process intensification for gas-liquid reactions." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318719.
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Hackett, L. A. "Gas-liquid mixing in stirred tanks." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373092.
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Brown, Alistair. "Protein recovery using gas-liquid dispersions." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312575.
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Rigopoulos, Stylianos. "Modelling of gas-liquid precipitation systems." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397258.
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Hickling, Simon James. "Liquid crystal polymers for gas chromatography." Thesis, University of Bath, 1999. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760726.
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Ismail, Mohd Halim Shah. "Hot gas desulphurisation using liquid tin." Thesis, University of Sheffield, 2008. http://etheses.whiterose.ac.uk/10317/.
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Present integrated gasification combined cycle (IGCC) systems demonstrate high /stem efficiency and impressive environmental performance, giving them an edge over conventional pulverised fuel power stations. A key area in the development of IGCC is hot fuel gas clean-up (HGCU). Fuel gas cleaning at elevated temperatures reduces thermal efficiency losses associated with gas quenching in conventional coal gas cleaning methods. The current hot gas clean-up method centres on the use of metal oxide sorbents for sulphur removal and the utilisation of a ceramic barrier filter for particulate cleaning. A fresh and radical approach may provide the key to overcoming the inherent limitations associated with metal oxide sorbents.
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Ventura, Sónia Patrícia Marques. "Gas liquid equilibria at high pressures." Master's thesis, Universidade de Aveiro, 2007. http://hdl.handle.net/10773/4865.
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Mestrado em Medição de Equilíbrios Gás Líquido a Altas PressõesEste trabalho tem como objectivo a medição da solubilidade de gases em líquidos a altas pressões. Para a realização experimental foi usada uma célula de altas pressões de volume variável e um método de observação directa para a detecção das transições de fase. As condições usadas neste trabalho experimental foram temperaturas entre 276.00 e 373.15 K e pressões ate 100 MPa. Numa primeira fase foram efectuadas medições de solubilidade de metano em anilina pura e para uma solução aquosa de composição mássica igual a 5% em anilina. A anilina é fundamentalmente usada em processos como a produção de borracha, de poliuretanos, pigmentos e tintas, fármacos, herbicidas e fungicidas. É usualmente produzida através de processos de redução do nitrobenzeno por reacção com o HCl. De facto, esta síntese é um processo químico complexo onde um grande número de processos compete entre si. Alterações nas condições do processo com a possível formação de produtos intermediários podem afectar a eficiência do processo. Para a sua melhoria foi sugerido que o hidrogénio usado fosse simultaneamente produzido e gasto no reactor principal. Neste caso e para a produção do mesmo, era necessário adicionar metano e água ao reactor. Tendo por base a ideia de que as reacções onde o hidrogénio é reagente e produto ocorrem em simultâneo, torna-se clara a importância do estudo da solubilidade do metano em anilina pura e em soluções aquosas desta. Numa segunda fase foi estudada a solubilidade do dióxido de carbono em soluções aquosas de tri-iso-butil(metil)fosfónio tosilato, com composições molares são de 4, 8 e 12% em líquido iónico. Este pertencente à família dos fosfónios. Possui uma viscosidade e densidade elevadas, é térmica e quimicamente estável e ainda possui uma elevada polaridade. Apresenta uma miscibilidade completa em água e nos solventes mais usuais, como o diclorometano e tolueno, não sendo no entanto míscivel em hexano. O tri-isobutil( metil)fosfónium tosilato é usado como solvente nos processos de hidroformilação de olefinas e ainda em processos de captura e conversão de dióxido de carbono. Neste trabalho experimental, a temperatura e a pressão foram inicialmente aumentadas até o sistema atingir o equilíbrio. A pressão é diminuída lentamente até se verificar o aparecimento/desaparecimento da última bolha de gás. A pressão à qual a última bolha de gás desaparece representa a pressão de equilíbrio para aquela temperatura. Este procedimento foi efectuado para vários sistemas e várias temperaturas.
The aim of this work is the measurement of the solubilities of different gases in different liquids systems at high pressures. A variable volume high pressure cell was used to perform the measurements based on the visual synthetic method for the detection of phase transitions. The conditions used in this work were temperatures ranging from 276.00 to 373.15 K and pressures up to 100 MPa. The first step of this work was the measurement of methane’s solubility in pure aniline and for one aqueous solution of 5% (w/w) in aniline. The main applications of aniline are the manufacture of polyurethane, rubber, dyes and pigments, drugs and agrochemicals (herbicides and fungicides). This compound is normally produced by reduction of nitrobenzene by reaction with HCl. In fact, that synthesis is a complex chemical process where a number of competing processes contribute to the final product. Changes in process conditions with the possible formation of intermediates can act as catalyst poisons that change the process’s efficiency. For the improvement of the production process it was suggested that the hydrogen, used for the reduction of the nitrobenzene, could be simultaneously generated and used in the main reactor. In this case for the in situ production of hydrogen it would be necessary the addition of methane and water in the reactor. Having in mind that these reactions occur simultaneously, it becomes clear the importance of studying the solubility of methane in aniline and in its aqueous solutions. In the second step the solubility of carbon dioxide in aqueous solutions of triiso- butyl(methyl)phosphonium tosylate with molar compositions of 4, 8 and 12% molar of ionic liquid, was studied. This compound belongs to the phosphonium - based ionic liquids family. It is characterized by a high viscosity and density. It is thermal and chemically stable and has a high polarity. This compound is totally miscible with water as well as with common organic solvents such as dicloromethane and toluene but is not miscible with hexane. The main applications of Tri-iso-butyl(methyl)phosphonium tosylate are like solvents in the hydroformylation of olefins and in processes of capture and conversion of carbon dioxide. In this experimental work, temperature and pressure were slowly increased until the system becomes homogeneous. After that, the pressure is slowly decreased until the appearance/disappearance of the last bubble of gas. The pressure at witch the last bubble disappears represents the equilibrium pressure for that temperature. This procedure was repeated for several systems and several temperatures.
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Orain, Mikaël. "Experiments with gas and liquid-fuelled flames." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252000.
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Salih, M. A. "Effects of antifoams on gas-liquid dispersion." Thesis, Swansea University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638752.
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The use of antifoam solution to control any foaming tendency is a very important aspect of fermentation processes. However, an antifoam solution will affect the mass transfer characteristics of a fermentation broth as well as suppressing foam so that both mass transfer and foam behaviour have been studied in the present work. The behaviour of a transient foam, which is produced by the antifoam itself, was investigated by means of a small two-dimensional bubble column. This bubble column consisted of two glass plates separated by a 10 mm thick frame of PTFE. Bubbles were produced from sintered-glass spargers of two pore sizes. Measurements of the average bubble diameters in the foam for different concentrations of solution were carried out from still photographs of the foam using an image analyzer. Two types of antifoams were investigated, polypropylene glycol (PPG) and a silicone oil emulsion. The two PPG concentrations used were 0.05 and 0.15 g/l both with and without adjustment of the pH and the addition of an electrolyte, NaCl. The silicon emulsion concentration was 0.015 g/l. Bovine serum albumen BSA as a foaming agent at a concentration of 0.20 g/l was investigated by itself, and with each of the antifoams. In each experiment, the height of foam layer was recorded as a function of the superficial gas velocity. A constant flow tank has been designed to allow the foam to overflow and to enable measurements of the mass transfer characteristics of the froth (or broth) layer only. These characteristics are: volumetric mass transfer coefficient KLA, Sauter mean bubble diameter b, gas hold-up g, interfacial area A, and mass transfer coefficient KL. The value of KLA was calculated from a mass balance of steady-state dissolved oxygen. The gas hold-up was estimated from the differences in heights of gassed and ungassed solution. A photographic technique was applied to measure the bubble diameter. Thus, the interfacial area A was simply calculated using the formula (A = 6 g / b). Finally, the value of KL value was determined.
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Ng, Sin Yuan. "Gas-liquid separation using axial flow cyclones." Thesis, University of Sheffield, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419640.
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de, Sá Ribeiro Albina Maria. "Studies of gas-liquid flow in bends." Thesis, University of Birmingham, 1994. http://etheses.bham.ac.uk//id/eprint/5069/.
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The present investigation is concerned primarily with air-water flow in a horizontal 0.032 m ID tube, and the influence of a 90° horizontal bend on the flow characteristics. Visualisation studies using high speed still photography and cine film, and entrainment and drop size measurements were conducted before and after the bend. Entrained mass fluxes were determined from film flow measurements carried out using the film removal technique, while the drop size distributions were measured with a laser diffraction technique. During these measurements the pressure in the test section was held between 1.0-1.4 bar, and at ambient temperature. Prior to the horizontal flow study, drop size and film flow rates were measured for vertical air-water flow in a 0.01026 m ID tube. This extended the work of Jepson (1992) who reported the effect of gas density and surface tension on film flow rate, drop size and deposition mass transfer coefficient. Modifications to the equipment described by Jepson (1992) allowed an extension of the measurements to higher flow conditions. The visualisation study was taken across flow conditions that include stratified, annular and pseudo-slug flow regimes. Still photographs show the presence of air bubbles entrained in the liquid film, and the creation of liquid drops at the crest of roll waves. Drops were seen to be entrained from the liquid film by both bag break-up and ligament break-up mechanisms. At the bend, the phenomenon of film inversion was seen to occur. Also, a secondary flow existing in the gas phase at the bend can be responsible for a swirl movement observed in the liquid film, in which at the upper part of the tube the liquid was pulled from the outer wall of the bend to the top of the tube in an anti-clockwise, cork screwing fashion. In the lower half, the liquid film was drawn from the outer wall towards the bottom of the tube in a clockwise motion. From the cine films, information on drop velocity was also extracted. This showed the axial drop velocity to be constant over the time frame of analysis. No significant correlation was found between the drop size and the axial drop velocity. The entrainment results in the horizontal tube showed that for stratified/annular conditions the entrained liquid mass flux increases with liquid flow rate (for a fixed gas flow rate), and in some instances plateau conditions were reached. However, for the pseudo-slug regime the level of entrainment falls considerably. For the whole range of flow conditions studied, the entrained liquid mass flux increases with superficial gas velocity, except for GL = 10 kg/m 2 s where the amount of entrainment is constant. The reduction in entrained liquid mass flux after the bend above certain flow conditions, is caused by drops depositing on the outside wall of the bend. For the flow conditions under study, the Sauter mean diameter varies between 60-110 um. Gas velocity has a strong influence on drop size, ie, the higher the gas velocity the smaller the drop size. The effect of liquid flow rate is somewhat more complex. At the lower liquid flow rates, drop size seems to be controlled by the entrainment mechanisms, while at the higher liquid flows drop coalescence has a dominant effect. The influence of the 90° bend on the drop size distribution was to increase the diameter of the drops. Both the entrained liquid mass flux and drop size were found to be lower for horizontal annular flow than in vertical flow, for the same flow conditions and tube diameter. The measurements carried out for air-water flow in the vertical 0.01026 m ID tube, showed the entrained mass flux to increase with both gas and liquid flow rates. For the flow conditions analysed, the Sauter mean diameter varies between 26-45 um. Drop size was seen to be influenced by gas and liquid flow rates, following similar trends to those observed during the horizontal study.
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Khan, Saad A. 1958. "Rheology of large gas fraction liquid foams." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15292.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE.
Bibliography: leaves 254-256.
by Saad Akhtar Khan.
Ph.D.
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Völkel, Norbert. "Design and characterization of gas-liquid microreactors." Thesis, Toulouse, INPT, 2009. http://www.theses.fr/2009INPT020G/document.
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Cette étude est dédiée à l'amélioration du design des microréacteurs gaz-liquide. Le terme de microréacteur correspond à des appareils composés de canaux dont les dimensions sont de l’ordre de quelques dizaines à quelques centaines de microns. Grâce à la valeur importante du ratio surface/volume, ces appareils constituent une issue prometteuse pour contrôler les réactions rapides fortement exothermiques, souvent rencontrées en chimie fine et pharmaceutique. Dans le cas des systèmes gaz-liquide, on peut citer par exemple les réactions de fluoration, d’hydrogénation ou d’oxydation. Comparés à des appareils conventionnels, les microréacteurs permettent de supprimer le risque d’apparition de points chauds, et d’envisager le fonctionnement dans des conditions plus critiques, par exemple avec des concentrations de réactifs plus élevées. En même temps, la sélectivité peut être augmentée et les coûts opératoires diminués. Ainsi, les technologies de microréacteurs s’inscrivent bien dans les nouveaux challenges auxquels l'industrie chimique est confrontée ; on peut citer en particulier la réduction de la consommation énergétique et la gestion des stocks de produits intermédiaires. Les principaux phénomènes qui doivent être étudiés lors de la conception d’un microréacteur sont le transfert de matière et le transfert thermique. Dans les systèmes diphasiques, ces transferts sont fortement influencés par la nature des écoulements, et l'hydrodynamique joue donc un rôle central. Par conséquent, nous avons focalisé notre travail sur l’hydrodynamique de l’écoulement diphasique dans les microcanaux et sur les couplages constatés avec le transfert de masse. Dans ce contexte, nous nous sommes dans un premier temps intéressés aux régimes d’écoulement et aux paramètres contrôlant la transition entre les différents régimes. Au vu des capacités de transfert de matière et à la flexibilité offerte en terme de conditions opératoires, le régime de Taylor semble le plus prometteur pour mettre en œuvre des réactions rapides fortement exothermiques et limitées par le transfert de matière. Ce régime d'écoulement est caractérisé par des bulles allongées entourées par un film liquide et séparées les unes des autres par une poche liquide. En plus du fait que ce régime est accessible à partir d’une large gamme de débits gazeux et liquide, l'aire interfaciale développée est assez élevée, et les mouvements de recirculation du liquide induits au sein de chaque poche sont supposés améliorer le transport des molécules entre la zone interfaciale et le liquide. A partir d'une étude de l’hydrodynamique locale d’un écoulement de Taylor, il s’est avéré que la perte de charge et le transfert de matière sont contrôlés par la vitesse des bulles, et la longueur des bulles et des poches. Dans l’étape suivante, nous avons étudié l'influence des paramètres de fonctionnement sur ces caractéristiques de l’écoulement. Une première phase de notre travail expérimental a porté sur la formation des bulles et des poches et la mesure des champs de vitesse de la phase liquide dans des microcanaux de section rectangulaire. Nous avons également pris en compte le phénomène de démouillage, qui joue un rôle important au niveau de la perte de charge et du transfert de matière. Des mesures du coefficient de transfert de matière (kLa) ont été réalisées tandis que l'écoulement associé était enregistré. Les vitesses de bulles, longueurs de bulles et de poches, ainsi que les caractéristiques issues de l’exploitation des champs de vitesse précédemment obtenus, ont été utilisées afin de proposer un modèle modifié pour la prédiction du kLa dans des microcanaux de section rectangulaire. En mettant en évidence l'influence du design du microcanal sur l’hydrodynamique et le transfert de matière, notre travail apporte une contribution importante dans le contrôle en microréacteur des réactions rapides fortement exothermiques et limitées par le transfert de matière. De plus, ce travail a permis d'identifier certaines lacunes en termes de connaissance, ce qui devrait pouvoir constituer l'objet de futures recherchesThe present project deals with the improvement of the design of gas-liquid microreactors. The term microreactor characterizes devices composed of channels that have dimensions in the several tens to several hundreds of microns. Due to their increased surface to volume ratios these devices are a promising way to control fast and highly exothermic reactions, often employed in the production of fine chemicals and pharmaceutical compounds. In the case of gas-liquid systems, these are for example direct fluorination, hydrogenation or oxidation reactions. Compared to conventional equipment microreactors offer the possibility to suppress hot spots and to operate hazardous reaction systems at increased reactant concentrations. Thereby selectivity may be increased and operating costs decreased. In this manner microreaction technology well fits in the challenges the chemical industry is continuously confronted to, which are amongst others the reduction of energy consumption and better feedstock utilization. The main topics which have to be considered with respect to the design of gasliquid μ-reactors are heat and mass transfer. In two phase systems both are strongly influenced by the nature of the flow and thus hydrodynamics play a central role. Consequently we focused our work on the hydrodynamics of the two-phase flow in microchannels and the description of the inter-linkage to gas-liquid mass transfer. In this context we were initially concerned with the topic of gas-liquid flow regimes and the main parameters prescribing flow pattern transitions. From a comparison of flow patterns with respect to their mass transfer capacity, as well as the flexibility offered with respect to operating conditions, the Taylor flow pattern appears to be the most promising flow characteristic for performing fast, highly exothermic and mass transfer limited reactions. This flow pattern is characterized by elongated bubbles surrounded by a liquid film and separated from each other by liquid slugs. In addition to the fact that this flow regime is accessible within a large range of gas and liquid flow rates, and has a relatively high specific interfacial area, Taylor flow features a recirculation motion within the liquid slugs, which is generally assumed to increase molecular transport between the gas-liquid interface and the bulk of the liquid phase. From a closer look on the local hydrodynamics of Taylor flow, including the fundamentals of bubble transport and the description of the recirculation flow within the liquid phase, it turned out that two-phase pressure drop and gas-liquid mass transfer are governed by the bubble velocity, bubble lengths and slug lengths. In the following step we have dealt with the prediction of these key hydrodynamic parameters. In this connection the first part of our experimental study was concerned with the investigation of the formation of bubbles and slugs and the characterization of the liquid phase velocity field in microchannels of rectangular cross-section. In addition we also addressed the phenomenon of film dewetting, which plays an important rôle concerning pressure drop and mass-transfer in Taylor flow. In the second part we focused on the prediction of gas-liquid mass transfer in Taylor flow. Measurements of the volumetric liquid side mass transfer coefficient (kLa-value) were conducted and the related two-phase flow was recorded. The measured bubble velocities, bubble lengths and slug lengths, as well as the findings previously obtained from the characterization of the velocity field were used to set-up a modified model for the prediction of kLa-values in μ-channels of rectangular cross-section. Describing the interaction of channel design hydrodynamics and mass transfer our work thus provides an important contribution towards the control of the operation of fast, highly exothermic and mass transfer limited gas-liquid reactions in microchannels. In addition it enabled us to identify gaps of knowledge, whose investigation should be items of further research
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Zou, Yiran. "Gas separation using supported ionic liquid membranes." Thesis, Queen's University Belfast, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517535.
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Abdulahi, Abolore. "Investigating the effect of liquid viscosity on two-phase gas-liquid flows." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/30935/.
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Simultaneous flow of gas-liquid in pipes presents considerable challenges and difficulties due to the complexity of the two-flow mixture. Oil-gas industries need to handle highly viscous liquids, hence studying the effect of changing the fluid viscosity becomes imperative as this is typically encountered in deeper offshore exploration. This work looks at the effect of liquid viscosity on gas-liquid flows. The work was carried out using two different pipes of 67mm and 127mm internal diameter. For the experiments carried out on the 67mm diameter pipe, air and three different liquids were used with viscosities 1, 42 and 152cp. With these experiments, the effect of viscosity on the entrainment process from the Taylor bubble in a vertical tube was investigated with the Taylor bubble being held stationary in a downward liquid flow with the use of three different gas injection methods. Taylor bubble length, the gas flow rate and the liquid flow rate approaching the stationary bubble were varied. In addition, the wake length below the stationary bubble was measured at different conditions of gas and liquid superficial velocities and comparison was made with the work by previous authors. Videos were taken with high speed camera to validate the measurement taken on wake lengths. A Wire Mesh Sensor system was placed at two different positions below the air injection point on the 67mm diameter pipe of the stationary bubble facility whose data acquisition provided time and cross-sectionally resolved information about spatial distribution. This information was used to generate time averaged void fraction, bubble size distribution and contour plots of the two-phase flow structure. A Probability Density Function (PDF) of void fraction can be obtained from the former, with PDFs of the wake section of the stationary bubbles showing that the flows are in the bubbly region while the PDF for the entire slug unit assumed that for a typical twin-peaked slug flow. The interpretation of this is that holding a bubble stationary can simulate real slug flow. Results on the bubble length measurement and gas loss into a bubble wake have shown good agreement with existing work by other authors. Experiments on the 127 mm diameter pipe were carried out because most published work on gas/liquid flow were on smaller diameter pipes with air and water, yet many of the industrial applications of such flows in vertical pipes are in larger diameter pipes and with liquids which are much more viscous than water. Another important parameter considered in the study is pressure because of its effect on gas density. This part of the research goes some way to rectify this lack and presents void fraction and pressure gradient data for sulphur hexafluoride with gas densities of 28 and 45 kg/m3 and oil (viscosity 35 times water). The gas and liquid superficial velocities were varied in the ranges 0.1-3 and 0.1-1 m/s respectively. The void fraction was also measured with a Wire Mesh Sensor system. Flow patterns were identified from the signatures of the Probability Density Function of cross-sectionally averaged void fraction. These showed the single peak shapes associated with bubbly and churn flow but not the twin-peaked shape usually seen in slug flow. This confirms previous work in larger diameter pipes but with less viscous liquids. For the bubble to churn flows investigated, the pressure gradients decreased with increasing superficial gas velocity. The change in pressure ultimately affects the density of gas in the two-phase flow mixture. Though there was little effect of pressure on void fraction below certain transitional flow rates, the effect became significant beyond these values. Different statistical analysis techniques such as power spectral density, probability density function, mean, standard deviation and time series of the acquired data have been used which also show the significant effect of pressure on void fraction at high gas density which have not been measured previously.
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Barma, Rajan. "Studies in mass transfer from single gas bubbles in gas liquid systems." Thesis, Teesside University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283232.
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Klande, Tobias [Verfasser]. "Contributions to the development of oxygen-transporting materials as ceramic membranes for gas separation / Tobias Klande." Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2013. http://d-nb.info/1035470306/34.
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Barghi, Shahzad. "Segregation and defluidized zones in liquid-solid and gas-liquid-solid fluidized beds." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0014/NQ42561.pdf.
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Wälchli, Severin. "Two-phase flow characteristics in gas-liquid microreactors /." Zürich, 2005. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16116.
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Kadic, Enes. "Survey of gas-liquid mass transfer in bioreactors." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1476312.
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Abadie, Thomas. "Hydrodynamics of gas-liquid Taylor flow in microchannels." Phd thesis, Toulouse, INPT, 2013. http://oatao.univ-toulouse.fr/11986/1/abadie.pdf.
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This thesis focuses on the hydrodynamics of gas-liquid Taylor flow (or slug flow) in microchannels. These flows, which are generally dominated by surface tension forces, have been investigated in rectangular channels of various cross-sectional aspect ratios by means of both experimental visualizations and numerical simulations. The first experimental part aims at characterizing the bubble generation process (bubble length and frequency of break-up) depending on the operating conditions, the fluid properties, as well as the junction where both fluids merge. Numerical simulations of fully developed Taylor flow have been carried out with the JADIM code. The computation of such surface tension dominated flows requires an accurate calculation of the surface tension force. Some limitations of the Volume of Fluid method have been highlighted and a Level Set method has been developed in order to improve the calculation of capillary effects. Both methods have been compared in detail in terms of spurious currents. 3D numerical simulations have been performed and the influence of the capillary number, as well as the effects of geometry have been highlighted. Inertial effects have been taken into account and their influence on the pressure drop has been shown to be non-negligible. Mixing in the liquid slug has also been studied.
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Krothapalli, Deep. "Gas-liquid Mass Transfer in Oxygen Delignification Systems." Fogler Library, University of Maine, 2004. http://www.library.umaine.edu/theses/pdf/KrothapalliD2004.pdf.
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Hida, H., M. Shikida, M. Okochi, H. Honda, and K. Sato. "Gas-Liquid Separated Resonator for Bio-Chemical Application." IEEE, 2009. http://hdl.handle.net/2237/13969.
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Rutledge, Joyce. "Design and analysis of a liquid/gas seal." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/19170.
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Hepworth, Neil James. "Characterisation of gas-liquid dispersions for beer analogues." Thesis, Imperial College London, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405005.
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Costigan, G. "Flow pattern transitions in vertical gas - liquid flows." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361925.
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Thompson, V. "Structural integrity of liquid natural gas storage tanks." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371581.
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Hernandez, Perez Valente. "Gas-liquid two-phase flow in inclined pipes." Thesis, University of Nottingham, 2008. http://eprints.nottingham.ac.uk/11764/.
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In order to understand the behaviour of two-phase flow in inclined pipes, an extensive programme of work has been undertaken using the Inclinable Facility in the laboratories of the School of Chemical, Environmental and Mining Engineering at the University of Nottingham. The test pipe (6.5 m long) could be positioned at angles between -20° downwards and vertical upwards. Two pipe diameters were used; namely 38 mm and 67 mm. The fluids used were air and water. Superficial velocities for air ranged from 0.15 to 8.9 m/s and from 0.04 m/s to 0.7 m/s for water. Time series of liquid holdup (using capacitance probes) and pressure drop (differential pressure transducer) were measured. In addition, a high speed video system was used in order to obtain image sequence of the flow under different selected conditions. It was found that for upward inclined flow most of the experiments fall within the slug flow regime whereas for inclined downward flow the dominant flow pattern is stratified flow. For horizontal flow, the flow regime depends more on the gas and liquid superficial velocities. Data for liquid holdup, pressure drop, frequency and translational velocity of periodical structures are reported. Comparisons with literature correlations and data are performed as well. Frequency was found to be strongly affected by inclination angle and a correlation has been proposed. An effect of the pipe diameter is also found under certain flow conditions mainly on the liquid holdup, pressure drop and structure velocity. Increase of pipe diameter displaces the bubbly-slug transition to the right hand side on the flow pattern map for inclined flow, and for horizontal pipe the stratified-slug transition is moved up. In addition, a CFD code has been used to successfully model the hydrodynamics of In addition, a CFD code has been used to successfully model the hydrodynamics of the slug flow pattern, using the Volume of Fluid model based on the Euler-Euler approach. The modeling results are validated with the experiments and also provide more detailed information on the flow such as the velocity field.
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Alamu, Mhunir Bayonle. "Investigation of periodic structures in gas-liquid flow." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/12228/.
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Liquid hold-up is seen to increase as liquid viscosity and fraction of gas taken off increases suggesting corresponding increase in partial separation of phases. However, effect of liquid viscosity does not become significant until a threshold is exceeded when fraction of gas taken off equals 0.40. In all cases examined, periodicity of flow structures is observed to increase as liquid viscosity increases. Considering the results of the three investigations carried out, it can be concluded that periodicity of two-phase flow structure increases as liquid viscosity increases and transition to co-current annular flow occurs at gas superficial velocity of 21 m/s.
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Gezrok, Klaus. "Hydrodynamics of high phase fraction gas-liquid reactors." Thesis, University of Birmingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.518091.
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Rees, G. J. "Interfacial adsorption in a gas-liquid chromatographic system." Thesis, Swansea University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638636.
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Chromatographic retention due to adsorption at the liquid/gas and liquid/solid interfaces is possible in gas-liquid chromatographic (GLC) systems, especially with polar solutes from a non-polar stationary phase. The variation of retention volumes with sample size at 60oC on several series of columns, using different support materials, was studied for di iso-propyl ether (DIPE), a polar solute, on squalane, a non-polar stationary phase. Isolation of the total adsorption contributions to retention was then performed using a semi-empirical curve fitting procedure devised by Mathiasson and Jonsson. The adsorption retentions at infinite dilution on a fully wetted porous silica support (Porasil F) was extrapolated to zero loading where the gas/liquid interfacial area (Ax) approaches the value of the support surface area (As). As was measured using the BET nitrogen adsorption method, and the sum of the support/liquid and vapour/liquid adsorption coefficients was obtained. The solid/liquid interfacial adsorption coefficient, Ks, was estimated from adsorption liquid chromatographic parameters, and was found to be small in comparison with the gas/liquid interfacial adsorption coefficient, Kx. The variation with liquid loading of the adsorption contribution to retention on two silanised supports (Chromosorb P-AW DMCS and HMDS treated Porasil F) was studied. The gas liquid interfacial area at high loading was found to be small in comparison with that of untreated Porasil F, and comparable with values obtained by other workers. At squalane loadings where a wetting transition is postulated on the silanised support, the magnitude of Ax approaches that of the unsilanised support, and helps confirm the model for the wetting transition proposed by Conder and coworkers.
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Geraci, Giorgio. "Gas-liquid flows in inclined pipes and venturis." Thesis, University of Nottingham, 2006. http://eprints.nottingham.ac.uk/14313/.
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In oil industrial applications, the modem practice in the drilling of oil wells, deviated drilling, results in inclinations from the vertical to the horizontal being present in such wells. Their design requires an accurate knowledge of the pressure drop/flowrates/physical-properties relationships. The measurement of wet-gas streams can be improved significantly by the use of a Venturi flow meter with an "overreading" correction. Moreover, at high gas mass fractions, knowledge of the liquid distribution about the well tubing cross section is required to inform policy on the use of inhibitors to protect the tubing from corrosion. Therefore, the aims of this study are to address aspects of two-phase gas/liquid flow in the pipe upstream the Venturi and in the Venturi. The main thrust of the project is to examine the effects of stratification that occur in annular flow when the pipe inclination is from horizontal to much higher inclinations. The study of annular flow includes the prediction of the three principal dependent variables – film flowrate, film thickness and pressure drop - as a function of position along the channel. All experiments were carried out with air and water in an inclinable rig. It consisted of a 5 m long stainless steel pipe of 38 mm internal diameter. The pipe could be positioned at any angle between horizontal and vertical in intervals of 5 degrees. The Venturi, located downstream the pipe, had a 19 mm i.d. throat and angles of convergent and diffuser respectively of 32° and 4°. Measurements on liquid film flowrate and liquid film thickness were carried on with two conductance probe techniques and sintered porous wall units. Measurements on pressure drop were conducted with the use of two differential pressure cells. In all experiments described, gas and liquid flowrates and pipe orientation were varied. Another aim of the study was to develop computer modelling for the prediction of air-water pressure gradient and liquid film thickness along the Venturi. The models of Azzopardi et al. (1991) regarding pressure drop and the models of Fukano and Ousaka (1988) for film thickness circumferential variations have been analysed and modified according to the characteristics of the system.
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Oliveira, Monica Sofia Neves de Freitas. "Characterisation of a gas-liquid oscillatory baffled column." Thesis, Heriot-Watt University, 2003. http://hdl.handle.net/10399/403.
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