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 87 for “"gas velocity"”.
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An investigation of the effect of a tangential gas velocity on combustion instability.
A small, uncooled research rocket motor was built to study the effects of a vortex flow on combustion instability. Normal heptane and air were used as propellants with the air being divided into two flows; a primary flow at the center of the combustion chamber and a secondary flow at the periphery …
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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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Hydrodynamics, Mixing, and Mass Transfer in Bubble Columns with Internals
… the effects of vertical cooling internals on the gas hydrodynamics, gas mixing, and mass transfer. In addition, this study attempts to develop and validate models that can simulate the radial gas velocity profile and axial gas mixing in the presence and absence of internals. Finally, this work …
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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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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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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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Uncertainty Quantification and Accuracy Improvement of the Double-Sensor Conductivity Probe for Two-Phase Flow Measurement
… show improved accuracy for void fraction, gas velocity and superficial gas velocity, compared to the original probe measurements. High-resolution two-phase flow data is essential for the further development of various two-phase flow models and validation of two-phase CFD codes. Therefore, a …
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Numerical Modeling and Prediction of Bubbling Fluidized Beds
… to determine pressure drop, minimum fluidization velocity and segregation for bubbling fluidized beds. The computational fluid dynamics (CFD) code Multiphase Flow with Interphase eXchange (MFIX) is used to study a two-stage reactor geometry with a binary mixture. MFIX is demonstrated to accurately …
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Numerical Modeling of Air-Water Flows in Bubble Columns and Airlift Reactors
… by varying the column diameter and the inlet gas velocity using two-dimensional simulations. The typical characteristics of a homogeneous, slug, and heterogeneous flow were shown by examining gas holdup. The flow field predicted using two-dimensional simulations of the airlift reactor showed a …
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Experimental investigation of local properties in two-phase fluid-flow hydrodynamics
Local, time-averaged measurements of gas void fraction, gas velocity, gas bubble diameter, and bubble passage frequency were made in a concurrent-flow, vertical rectangular channel (15.0 x 1.25 cm) having an aspect ratio of 12:1. Twenty (20) flows were analyzed with superficial gas and liquid …
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Downhole Gas Separator Performance in Sucker Rod Pumping System
… for a long time. One way to reduce the amount of gas entering into the pump is to use downhole gas separators. The main purpose of these devices is to facilitate agglomeration of gas bubbles so that they migrate upwards and can be released through the casing annulus. Design and selection of …
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Fluidized-Bed combustion of coal
… in terms of the bed temperature, superficial gas velocity and the static bed height within the following ranges of these parameters: Bed Temperature Gas Velocity Static Bed Height 700 to 10000C 0,9 to 1,5 m/s 150 to 230 mm by using a bed material substantially different from the coal feed, it …
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Mass transfer coefficients and effective area of packing
… mass transfer coefficient (k [subscript L]), and gas film mass transfer coefficient (k [subscript G]) of eleven structured packings and three random packings were measured consistently in a 0.428 m packed column. Absorption of CO₂ with 0.1 gmol/L NaOH with 3.05 m packing was used to measure a …
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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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Fast GC: Applications and Theoretical Studies
… of the compressibility of the mobile phase in gas chromatography and presents an equation derived from only two mutually independent variables. Solutions of decane and tridecane in hexane were analyzed at pressures ranging from 15 to 150 psi. Six different columns were used that varied in …
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Scaling and Performance of a Device for Fluidized Bed Entrainment Reduction
… were made of the particulate mass flux and gas velocity in the dilute phase. A probe was developed which determined the particle mass flux by counting electrical pulses produced when particles collided with a metal sensor placed in the flow stream. Air velocity was measured with a rugged hot …
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Carbon dioxide transfer through hollow fiber membranes
… that included a prediction of the internal axial gas concentrations within the fiber lumen. This model was validated by measuring bulk gas velocity within fiber lumen. A trend of increasing mass transfer coefficients with internal pressure was observed. A correlation for predicting this effect was …
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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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