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 35 for “"Superficial Gas Velocity"”.
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Gas-liquid simulation of an airlift bubble column reactor
… on industries such as bioprocess industries. The gas-liquid of two-phase fluid flow system has been carried out to investigate the hydrodynamics parameter. An Eulerian-Eulerian approach was used to model air as the dispersed phase within a continuous phase of water using the commercial software …
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Gas holdup in a gas-liquid-fiber semi-batch bubble column
… connected to one of three perforated plate gas distributors with open area ratios A = 0.57%, 0.99%, and 2.14% is employed to study gas holdup and flow regime in Rayon and Nylon fiber suspensions. This study determines the effect of superficial gas velocity, fiber type, fiber mass fraction, …
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Hydrodynamics and gas dispersion in industrial flotation cells
Solids suspension and gas dispersion studies were performed on a total of 40 industrial flotation cells of various types, sizes and duties in a Platinum Group Metal (pgm) concentrator in the North West Province of South Africa. The wide variety of cells studied included a Bateman 3-m³ cell, …
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Analysis of the thermal hydraulics of a multiphase oxygen production reactor in the Cu-Cl cycle
… water splitting process by Cu-Cl cycle, oxygen gas is produced by an endothermic thermolysis process in a three-phase reactor. In this thesis, the required heat for the thermolysis process is provided by adopting the idea of heating some of the stoichiometric oxygen gas by using a nuclear …
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Downdraft gasification of biomass
… were to investigate the parameters affecting the gasification process within downdraft gasifiers using biomass feedstocks. In addition to investigations with an open-core gasifier, a novel open-topped throated gasifier was designed and used. A sampling system was designed and installed to …
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The Effect of Operating Conditions on Gas Holdup and Mixing in Tower Fermenters
… conditions applicable to fermentation processes. Gas holdup was investigated thoroughly under different operating conditions in air-water systems. A number of fermentation media were also used as the liquid phase. It was found that apart from superficial gas velocity which is the governing factor …
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The effect of drop concentration on deposition in vertical annular two-phase flow
… and on the behavior of drops in the turbulent gas flow are needed. Experiments were conducted in a 4.2 cm vertical pipe at an upward superficial gas velocity of 36 m/s and at liquid mass flow rates from 30 to 170 g/s. Photographic drop size measurements were obtained. Measurements of …
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Mass transfer in bubble column contractors
Gas holdup and overall volumetric mass transfer coefficients in bubble column contactors have been investigated for water and aqueous electrolyte solutions. Two methods were used to obtain experimental data on volumetric mass transfer coefficients: the steady state oxidation technique and a …
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Visualizing fluidized beds with X-rays
<p>This study applies minimum fluidization velocity experiments, X-ray computed tomography (CT), X-ray stereography, and particle tracking to fluidized beds of glass beads, ground walnut shell, and ground corncob operating with a variety of flow conditions. 3-D local, time-averaged gas holdup is …
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Hydrodynamics and Mass Transfer in Bubble Columns
… used for assessing the effect of column size and gas and liquid flow rates on column hydrodynamics and reactor performance. Among these approaches, phenomenological models based on either single-class or multi-class bubbles that were validated on cold flow systems have been successful in …
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Hydrodynamic Characterization of 3D Fluidized Beds Using Noninvasive Techniques
… rates occur through the action of vertical gas injection into a column of solid particles. Although these properties give fluidized beds great advantages over other processing systems, the hydrodynamic characterization of fluidized beds is important for the efficient processing of many …
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Wall Heat Transfer Coefficient in a Molten Salt Bubble Column
… chloride (LiCl–KCl) eutectic by bubbling argon gas through the liquids. The column was operated at a temperature of 40 oC for the water experiments, at 75, 103 and 170 oC for the heat transfer oil experiments, and at 450 oC for the molten salt experiments. All the experiments were run at …
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Oxygen Mass-Transfer in Tower Fermenters
… of unsteady-state experiments. The effects of gas flow-rate, nutrient concentration, antifoams and microbial concentration on mass—transfer have been studied in detail: superficial air velocity and the presence of anti-foams are shown to be the most important factors. Measurements with the …
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Effect of Local Bed Hydrodynamics on the Distribution of Liquid in a Fluidized Bed
… the coker regions where bitumen is injected, the gas is a mixture of product vapors and steam. Steam introduced at different levels rises through the coker: the stripping steam is injected near the bottom, then the attrition steam above the stripper and finally the bitumen atomization steam. As a …
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CFD simulation of the dynamic flow behavior in a bubble column reactor
… to predict the bubbly flow parameter such as gas holdup, contact surface area, air volume fraction, pressure drop, and velocity magnitude to understanding the hydrodynamic flow behaviors. Three types of gas distributor design are tested on the 1.5 m height and 0.15 m diameter bubble column …
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Evaluating of scale-up methodologies of gas-solid spouted beds for coating triso nuclear fuel particles using advanced measurement techniques
… to evaluate the scale-up methodology of gas-solid spouted beds for hydrodynamics similarity that has been reported in the literature based on matching dimensionless groups and the new mechanistic scale up methodology that has been developed in our laboratory based on matching the radial …
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Void fraction measurements in large (0.3 m) diameter bubble column using Wire Mesh Sensor and Pressure transducers- Effect of sparger
… Experiments were performed for seven superficial gas velocities, to cover both Homogenous and Heterogenous flows. Two different spargers (point sparger and four arm spargers) were used to study the effect of the sparger design on the hydrodynamics. The measurement uncertainty of the …
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Void fraction measurements in a large (0.3 m) diameter bubble column using Wire Mesh Sensors and Pressure Transducers: Effect of Spargers
… Experiments were performed for seven superficial gas velocities, to cover both Homogenous and Heterogenous flows. Two different spargers (point sparger and four arm spargers) were used to study the effect of the sparger design on the hydrodynamics. The measurement uncertainty of the …
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Investigation of the hydrodynamics and scale-up of advanced TRISO nuclear fuel manufacturing using sophisticated measurement techniques
… of the hydrodynamics and scale-up of gas-solid spouted beds. The CT technique has been applied to study the effects of particle density, particle size, bed size, and superficial gas velocity on the gas-solid cross-sectional distributions of spouted beds. The CT results demonstrated …
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Investigation of local velocities and phase holdups, and flow regimes and maldistribution identification in a trickle bed reactor
… reactors are packed beds of catalyst on which gas and liquid reactants flow concurrently downward. In this work, the experimental work was carried out in 0.14 m diameter Plexiglas column using air-water system flowing over a packed bed of 3 mm glass bead particles. The local liquid and gas …
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