Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 27 for “"Bubble size distribution"”.
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Investigating the effect of perforation diameter and carbon dioxide bubble size distribution on heavy oil recovery
… the effect of perforation diameter and CO2 bubble size distribution on the viscosity and recovery of heavy oil during Enhanced Oil Recovery process. To conduct the investigation, an experimental rig was constructed to simulate the flow of CO2 in heavy oil. The oil viscosity, CO2 bubble sizes …
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An experimental study on the effect of viscosity on micro-bubble size distribution and rise velocity in a bubble column
… capacities. DAF systems generate microscale air bubbles to lift suspended particles in influent solution to the top of a rectangular tank and remove them by scrapers. Due to the recent focus on different applications of micro and nanoscale air bubbles across many industrial operations, …
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Theoretical and numerical study of air entrainment and bubble size distribution in strong free-surface turbulent flow at large Froude and Weber number
… key factor in controlling these processes is the size distribution of entrained bubbles. However, the underlying mechanisms/physics of air entrainment driven by free-surface turbulence (FST) and the resulted bubble size distribution still remain unclear. Therefore, detailed studies on air …
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Broadband acoustical scattering in coastal environments: application to gelatinous organisms
… acoustical techniques for characterizing microbubble populations have been established for decades, yet little is known about the spectral characteristics of dense microbubble clouds associated with estuarine tidal fronts. These bubbles facilitate air-sea gas exchange and could interfere with …
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Broadband acoustical scattering in coastal environments: application to gelatinous organisms and gas microbubbles
… acoustical techniques for characterizing microbubble populations have been established for decades, yet little is known about the spectral characteristics of dense microbubble clouds associated with estuarine tidal fronts. These bubbles facilitate air-sea gas exchange and could interfere with …
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Modeling of multiphase turbulent flow in continuous casting of steel
… these two paths is redistributed into small bubbles through complex gas redistribution processes, and the size distribution of the bubbles affects flow patterns as well as defect mechanisms in molds. Estimation of the exact amount of argon gas and size distribution of bubbles is crucial to …
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Effects of power-law entrainment on bubble fragmentation cascades
This thesis considers the evolution of the bulk bubble-size distribution 𝑁(𝑎,𝑡) of large bubbles (Weber number 𝑊𝑒 >> 1) under free-surface entrainment described generally by an entrainment size distribution 𝐼(𝑎) with power-law slope 𝛾 and large-radius cutoff 𝑎ₘₐₓ. The focus is the interaction …
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Texture and bubble size measurements for modelling concentrate grade in flotation froth systems
… the watershed algorithm for the measurement of bubble sixe distribution in flotation froths. Unlike the standard watershed algorithm, it is able to measure accurate bubble size distributions when both large and tiny bubbles are present in a flotation froth image. Flotation froths with “dynamic …
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Experimental and mathematical modeling of foamy-oil evolution and flow in the primary production and CO₂-based cyclic solvent injection
… bulk fluids. In addition, the nucleation of CH4 bubbles was found to be more instantaneous than that of CO2/C3H8 bubbles. Numerically, a robust kinetic reaction model in the commercial CMG-STARS module was utilized to simulate the solvent exsolution and liberation processes in the CCE and DFP …
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Intensification of Gas Absorption in a Downward Flow Microbubble Bioreactor
… economics requires reduction of reactor cost and size while maintaining high production rate via rapid delivery of gas feedstock to the liquid phase which in turn requires a high volumetric mass transfer rate (). One strategy to achieve this goal is to increase interfacial area density, …
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Análise experimental do efeito do ângulo de injeção de gás em um escoamento vertical ascendente de líquido
… in a upward vertical liquid flow, regarding the bubble size and shape distributions, as well as liquid velocity profile, both in the injection area. The experiments are carried in a 44 mm acrylic vertical pipe, in which water flows and air is injected through an angled device, in relation to the …
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The Development of a vision-based flotation froth analysis system
… on-line analysis of flotation froth images. The size and shape of bubbles that constitute the flotation froth convey considerable information on the performance of the flotation process. A method whereby this size and shape information can be automatically extracted from froth images is highly …
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The Development of a vision-based flotation froth analysis system
… on-line analysis of flotation froth images. The size and shape of bubbles that constitute the flotation froth convey considerable information on the performance of the flotation process. A method whereby this size and shape information can be automatically extracted from froth images is highly …
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Evaluation of Millimetre-wave Coherent Scattering from a Sea surface covered by Foam modelled as Sequences of Thin Phase-Scattering Screens using Split-Step Fourier Method
… based model of foam covered sea surface as air-bubble coated with thin layers of seawater, that is suitable for investigation of millimetre wave coherent scattering. The propagation media was described as a flat sea-surface covered by foam and modelled as sequences of thin and deep phase …
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Laboratory measurements of the sound generated by breaking waves
… were caused by the collective oscillation of bubble clouds. Void fraction measurements taken by Eric Lamarre were available for five breaking events and therefore the average sound speed inside the bubble clouds and their radii were known. Using this information the resonant frequencies of a …
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Computational fluid dynamics modelling of dissolved oxygen in oxidation ditches.
… contributions to knowledge are the effect of bubble size distribution (BSD) and biochemical oxygen demand (BOD) distribution on the DO distribution. Species transport modelling predicts the BOD and DO distribution in the ditch. De-oxygenation of local dissolved oxygen by BOD is modelled by an …
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The development of frother optimisation techniques in full scale flotation plants
… scale plant using the Anglo American Platinum Bubble Sizer (AAPBS) which is a commonly used tool by the plant metallurgist. The techniques developed have been based on the application of fundamental research of frothers in literature. This thesis consists of three main focus areas: 1) …
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Bubble dynamics in polymeric foams
… of fluid viscoelasticity on the expansion of gas bubbles in polymer foams for both non-reactive and reactive polymers are investigated. Polymer foams are used extensively in consumer products, from car parts to upholstery. They are produced either by injection moulding (of non-reactive polymeric …
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Viscous liquids in bubble columns
… viscous Newtonian and non-Newtonian liquids in bubble columns with, and without, draft tubes. The importance of the parameters influencing bubble column reactors is discussed with reference to previous work. The shapes and rise velocities of single bubbles in these liquids were studied in an …
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Vibrations for improving multiphase contact
… of two multi-phase contacting systems: a bubble column for gas-liquid contacting (physical absorption) and a Piston Oscillating Monolith Reactor (POMR) for gas-liquid-solid contacting (catalytic reactions). In a bubble column reactor, enhancements of mass transfer coefficient and gas hold …
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