Rozprawy doktorskie na temat „Bubble column”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Bubble column”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Urseanu, Maria Ioana. "Scaling up bubble column reactors". [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/83970.
Pełny tekst źródłaMcMahon, Andrew Martin. "Modelling the flow behaviour of gas bubbles in a bubble column". Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/5441.
Pełny tekst źródłaIncludes bibliographical references (leaves 96-99).
The bubble column reactor is commonly used in industry, although the fluid dynamics inside are not well understood. The challenges associated with solving multi phase flow problems arise from the complexity of the governing equations which have to be solved, which are typically mass, momentum and energy balances. These time-dependent problems need to include effects of turbulence and are computationally expensive when simulating the hydrodynamics of large bubble columns. In an attempt to reduce the computational expense in solving bubble column reactor models, a "cell" model is proposed which predicts the velocity flow field in the vicinity of a single spherical bubble. It is intended that this model would form the fundamental building block in a macroscale model framework that does predict the flow of multiple bubbles in the whole column. The non-linear Navier-Stokes (NVS) equations are used to model fluid flow around the bubble. This study focusses on the Reynolds number range where the linear Stokes equations can be used to accurately predict the flow around the bubble. The Stokes equations are mathematically easier to solve than the NVS equations and are thus less computationally expensive. The validity of the NVS model was tested against experimental data for the flow of water around a solid sphere and was found to be in close agreement for the Reynolds number range 25 to 80. The simulation results from the Stokes flow model were compared with those from the NVS flow model and were similar at Reynolds numbers below 1. The application is then in the partitioning of the bubble column into regions governed by either Stokes or NVS equations.
Shi, Weibin. "Dynamic modelling and simulation of turbulent bubbly flow in bubble column reactors". Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53960/.
Pełny tekst źródłaGandhi, Bimal C. "Hydrodynamic studies in a slurry bubble column". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28573.pdf.
Pełny tekst źródłaSharp, David Anthony. "Simulation of a two-dimensional bubble column". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0009/MQ60174.pdf.
Pełny tekst źródłaShen, Gang 1953. "Bubble swarm velocities in a flotation column". Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28529.
Pełny tekst źródłaIn a laboratory column, a bubble interface was created by introducing a step change of gas flow, and the rising velocity of this interface, $u sb{in},$ was measured using a conductivity method with the new conductivity meter. A measurement of the three-dimensional bubble swarm velocity in the column was obtained by interpolation from the $u sb{in}$ measured as a function of $J sb{g2} vert J sb{g} sb1 ,$ where $J sb{g} sb1$ and $J sb{g} sb2$ are the superficial gas velocities before and after a step change of gas flowrate, respectively. This velocity was referred to as the hindered velocity, $u sb{h}.$ The buoyancy velocity, $u sb0 ,$ was readily determined by switching off the gas, i.e. $u sb0 = u sb{in}$ at $J sb{g} sb2 = 0.$
The average gas velocity, $u sb{g},$ was corrected to the local average gas velocity, $u sb{g,loc},$ to obtain the average gas velocity under the local pressure conditions at a given vertical position in the column. The experimental results showed that $u sb{h}$ was significantly less than $u sb{g,loc}$ (and $u sb{g}).$ This is because the $u sb{h}$ is the three-dimensional bubble swarm velocity and $u sb{g,loc}$ is the one-dimensional bubble swarm velocity. Unlike $u sb{g,loc},$ the $u sb{h}$ was constant along the column, which was supported by theoretical momentum analysis. The $u sb{h}$ is proposed as the key characteristic swarm velocity of the system.
For the air-water only system in the two-dimensional domain, using parabolic models for gas holdup and liquid circulation velocity profiles over the cross section of the column, the $u sb{h}$ could be fitted to the experimental data. For the air-water-frother system, the $u sb{h}$ could not be fitted to the experimental data which is attributed to the air bubbles adopting a circulatory flow pattern.
In the air-water only system under batch operation, Nicklin's derivation (1962), i.e. $u sb{g} = u sb0 + J sb{g},$ was supported only under restrictive conditions, namely $u sb{g}$ and $J sb{g}$ must be measured at atmospheric pressure. Considering the local values, the experiments showed that $u sb{g,loc}$ was not equal to $u sb0 + J sb{g,loc}.$ In the presence of frothers under batch or countercurrent operation, the experiments showed that Nicklin's derivation was not applicable even if atmospheric values of $u sb{g}$ and $J sb{g}$ were used.
KHAN, KHURRAM IMRAN. "Fluid dynamic modelling of bubble column reactors". Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2528494.
Pełny tekst źródłaRajapakse, Sumanasiri D. N. "An experimental study on the effect of viscosity on micro-bubble size distribution and rise velocity in a bubble column". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2527.
Pełny tekst źródłaRahimi, Rahbar. "Heat transfer in bubble columns". Thesis, University of Bath, 1988. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380868.
Pełny tekst źródłaSyed, Alizeb Hussain. "Modeling of two & three phases bubble column". Thèse, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/11431.
Pełny tekst źródłaLe partenaire industriel de ce projet utilise un réacteur à suspension à trois phases pour la production de méthanol biogénique. Dans celui-ci, le gaz de synthèse est diffusé par barbotement dans la phase à suspension qui contient à la fois les phases liquide et solide. Les bulles en ascension présentent un large spectre de tailles et interagissent avec la phase à suspension en échangeant de la quantité de mouvement via leurs surfaces. Cet échange comprend les forces de trainé, de portance, de lubrification en proche parois et de dispersion par turbulence; lesquelles requièrent notamment le calcul de la taille moyenne des bulles. Une façon de prédire numériquement cette taille moyenne est de recourir à un modèle de bilan de population (PBM, de l’anglais Population Balance Model), qui peut être couplé avec un model multiphasique eulérien. Un tel PBM a requière des modèles de fermetures pour la coalescence et la rupture des bulles. Dans la présente étude, l'influence des modèles noyaux de coalescence et de rupture des bulles a été étudiée pour des systèmes à deux et à trois phases en utilisant l’approche eulérienne. L'influence de la taille du maillage, du nombre de classes de bulles, du schéma numérique, de la force de lubrification en proche parois et de la force de dispersion par turbulence sont également incluses. Dans un système bi-phasique, les résultats montrent que le modèle de coalescence Luo doit être ajusté lorsqu'il est utilisé en combinaison avec le noyau de rupture Luo. La combinaison des noyaux de coalescence Luo et de rupture Lehr (Luo-Lehr) montrent des profils radiaux moyennés dans le temps qui sont valides pour la concentration de gaz et la vitesse axiale du liquide par rapport aux mesures expérimentales. Dans le système triphasé, la combinaison des modèles noyaux de coalescence de Luo et de rupture de Lehr (Luo-Lehr) et de la coalescence de Luo et de rupture de Luo (Luo-Luo) prédisent des profils radiaux moyennés dans le temps qui sont valides pour la vitesse axiale moyenné dans le temps par rapport aux expériences. Cependant, à une vitesse de gaz superficielle élevée, ces profils prédisent un comportement non réaliste par rapport aux observations empiriques. Les résultats de l'analyse de sensibilité du maillage montrent qu’avec des cellules de 3 mm, le model prédit une tendance similaire aux valeurs empiriques pour les profils radiaux de concentration du gaz, de vitesse axiale du liquide et de vitesse axiale solide. Le nombre de classes de bulles influe sur les distributions prédites de taille de bulle dans le système triphasé alors que les schémas de discrétisation numériques n'ont aucune influence sur les résultats. Les résultats des simulations d’un banc d’essai avec diffuseur à bulles poreux montrent que tenir compte du terme de dispersion influence le comportement hydrodynamique de la colonne à bulles.
Marchese, Mecklenburg Mario. "Hydrodynamic study of a downwards concurrent bubble column". Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61167.
Pełny tekst źródłaThe conductivity technique using Maxwell's equation gave a maximum error of 6%, in both two- and three-phase systems (considering the water-solids mixture as one phase).
The drift flux model was applied to try to correlate the data. Both two- and three-phase systems showed consistent trends. The model was used to estimate bubble size. In the Richardson and Zaki equation the m factor was in the range 2.9 to 3.1. A dimensionless drift flux was defined assuming $m=3$ which fitted the data. For three-phase systems, however, the results predicted a trend in bubble size that seemed opposite to observation. (Abstract shortened by UMI.)
Sam, Abbas. "Single bubble behaviour study in a flotation column /". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=54427.
Pełny tekst źródłaDans une colonne de flottation carree (10 x 10 cm) a chemise d'eau faite de plexiglas transparent, on a mesurd, sur une distance de 400 cm, les profils de velocite axiale (velocite locale versus temps ou position) de bulles simples avec ou sans la presence de reactifs de flottation tel le moussant. En circulant de l'eau dans la chemise, la temperature du liquide a l'interieur de la colonne fut maintenue a une temperature constante de 30°C. On a etudie des bulles simples ayant des diametres d'intdret pour la flottation. Une frequence de Ondration des bulles fut choisie afm que la velocite soit independante de la frequence. Pour suivre la bulle lors de son ascension, on a utilisë une camera video montee sur rail et pouvant se placer verticalement a des vitesses variables. fr
McClure, Dale David. "Modelling Bubble Column Bioreactors Using Computational Fluid Dynamics". Thesis, The University of Sydney, 2014. http://hdl.handle.net/2123/12058.
Pełny tekst źródłaCox, Shane Joseph Chemical Sciences & Engineering Faculty of Engineering UNSW. "Design and analysis of a photocatalytic bubble column reactor". Awarded by:University of New South Wales, 2007. http://handle.unsw.edu.au/1959.4/37818.
Pełny tekst źródłaLeichtle, Gunther F. "Analysis of bubble generating devices in a deinking column". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0027/MQ50635.pdf.
Pełny tekst źródłaBhattacharya, Sujit. "Internal filtration system for three-phase slurry bubble column". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0012/MQ42125.pdf.
Pełny tekst źródłaLeichtle, Gunther F. "Analysis of bubble generating devices in a deinking column". Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21310.
Pełny tekst źródłaThe research is a comparison of industrial bubble generating devices in a pilot and laboratory column using water/Dowfroth and pulp sampled on-line from a local deinking plant. The pilot column tested combinations of 6, 4 and 2 stainless steel (ss) porous spargers, and filter cloth and jetting sparger; the lab column used a single ss porous sparger. Long term tests on the pilot column were also done to evaluate maintenance issues.
Trends from the water/Dowfroth tests were used to predict results using pulp. Six ss spargers outperformed the other spargers in all cases. The performance of the lab column sparger matched 4 spargers, with the filter cloth performing marginally better than the jetting sparger or 2 spargers.
Gas holdup (Eg) and bubble surface area flux (Sb) gave good correlation with ink removal with all spargers failing within a narrow range. Surface area flux is suggested over Eg unless bubble diameter or superficial gas velocity are indeterminable. Sb > 100 s-1 gave ink removals equal to the plant Voith cells. An Sb below 40 s-1 gave zero ink removal. The lab and pilot column followed slightly different trends which was attributed to column diameter (i.e., wall effects).
The ss and filter cloth spargers present long term maintenance issues due to plugging. The performance of the 6 ss spargers decreased more quickly than any other during the long term tests, attributed to lower air velocities per pore.
Marial, Jacob Mach. "Impact of Fluids Distribution System on Bubble Column Hydrodynamics". Thesis, Université d'Ottawa / University of Ottawa, 2021. http://hdl.handle.net/10393/42424.
Pełny tekst źródłaMyre, Denis. "Synthesis of Carbon Dioxide Hydrates in a Slurry Bubble Column". Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19789.
Pełny tekst źródłaBridges, P. A. "Foam and bubble column phenomena in viscous liquids and slags". Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315560.
Pełny tekst źródłaSkosana, Petrus Jabu. "Wall Heat Transfer Coefficient in a Molten Salt Bubble Column". Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46246.
Pełny tekst źródłaDissertation (MEng)--University of Pretoria, 2014.
tm2015
Chemical Engineering
MEng
Unrestricted
Coetzee, Waldo. "Development of a computationally efficient bubble column simulation approach by way of statistical bubble micro-flow modelling". Doctoral thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/5368.
Pełny tekst źródłaIncludes bibliographical references.
The intimate contact achieved between the gas and liquid phases in bubble columns, coupled with the inherent efficient mixing these reactors offer, yield excellent heat and mass transfer characteristics. These attributes have been exploited commercially for decades, however, due to the complexity of the underlying hydrodynamics, the prediction of bubble columns based on empirical models can be unreliable outside of the operating ranges used to fit these models. Computational Fluid Dynamics (CFD) has emerged as an attractive tool for simulating these reactors and is based on numerically approximating the fundamentally based Navier-Stokes equations on a discretized domain. The application of CFD has become more practical as the cost of computational resources has declined and has lead to the establishment of three distinct modelling approaches which have been evaluated for the purpose of bubble column simulation in a number of research papers over the past two decades. Here the Euler-Euler approach has been recommended for the simulation of large scale columns, however, this approach is based on the most assumptions and yields the least amount of flow field information. The Euler-Lagrange approach treats bubbles as discrete particles which allows for the incorporation of a deterministic bubble size distribution and the direct consideration of heat and mass transfer effects. The most fundamental approach, Direct Numerical Simulation (DNS), predicts flow properties at the bubble scale, however, is extremely computationally expensive and is therefore only practically applicable to the investigation of a very small number of bubbles. The objective of this study is to contribute to the simulation of gasliquid flow interaction occurring in bubble columns by proposing a novel technique for simulating bubble scale flow information at a significantly reduced computational expense. For this purpose, it is proposed to predict the micro-flow fields around individual bubbles, within an Euler-Lagrange framework, with an algebraic model termed the Bubble Cell Model (BCM). The high gradient regions around individual bubbles are thereby accounted for with an algebraic flow model that can be rapidly evaluated as opposed to the two-phase partial differential Navier-Stokes equations, thereby reducing the numerical complexity of the problem. Since no such flow models currently exist and accuracy and fast evaluation are imperative, a statistical approach to the construction of the BCM is justified.
Goraki, Fard Mojtaba. "CFD Modeling of Multiphase Turbulent Flows in a Bubble Column Reactor". Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670965.
Pełny tekst źródłaEste trabajo presenta el estudio numérico de flujos turbulentos bifásicos en un reactor de columna de burbujas en 3D utilizando diferentes modelos a diferentes escalas. En primer lugar se centra en la hidrodinámica, las transiciones del régimen de flujo y la transferencia de masa utilizando el modelo de mezcla Euler-Euler k-ε para amplios rangos de velocidades superficiales de gas. Se ha puesto énfasis se ha puesto en evaluar el rendimiento de este modelo y el análisis de las transiciones del régimen de flujo y el comportamiento del flujo transitorio dentro del reactor de columna de burbujas. Se presenta la cuantificación de las fuerzas interfaciales en diferentes partes del reactor. Se comparan diferentes modelos de la estimación del coeficiente global de transferencia de masa, como son el modelo de penetración por deslizamiento y el modelo de celdas de remolino, con los datos experimentales para analizar la transferencia de masa. Los resultados revelan algunos de los rasgos característicos de los regímenes de flujo homogéneos y heterogéneos en la circulación de líquidos, la retención de gas, las fluctuaciones turbulentas y la transferencia de masa gas-líquido.
This work presents numerical study turbulent two-phase flows in a 3D bubble column reactor using different models at different scales. The focus is first set on the hydrodynamics, flow regime transitions and mass transfer using the Euler-Euler mixture k-ε model at wide ranges of superficial gas velocities. The emphasis is to assess the performance of this model and the analysis of the flow regime transitions and the transient flow behavior inside the bubble column reactor. The quantification of the interfacial forces at different parts of the reactor are presented. Different models of the overall mass transfer coefficient estimation, namely the slip penetration model and the eddy cell model, are compared against the experimental data to analyze the mass transfer. The results reveal some of the characteristic features of homogeneous and heterogeneous flow regimes on the liquid circulation, gas holdup, turbulent fluctuations and gas-liquid mass transfer. For transient and turbulent flow regimes, Euler-Euler large eddy simulations were used for a reliable scale resolution. The flow is more dynamic, and more details of the instantaneous local flow structure have been obtained including large-scale structures and vortices developed in the bubble plume edge.
Li, Hanning. "Heat transfer and hydrodynamics in a three-phase slurry bubble column". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0028/NQ31161.pdf.
Pełny tekst źródłaZhang, Dongsheng. "Eulerian modeling of reactive gas-liquid flow in a bubble column". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/58021.
Pełny tekst źródłaSarrafi, Amir. "Studies of holdup, mixing, and heat transfer in bubble column reactors". Thesis, University of Surrey, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299033.
Pełny tekst źródłaTow, Emily Winona. "Heat and mass transfer in bubble column dehumidifiers for HDH desalination". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87970.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (pages 109-114).
Heat and mass transfer processes governing the performance of bubble dehumidifier trays are studied in order to develop a predictive model and design rules for efficient and economical design of bubble column dehumidifiers for humidification-dehumidification (HDH) systems. As a result of their high heat transfer coefficients and large interfacial areas, bubble columns are an inexpensive and compact solution for dehumidification in HDH, which has promising applications in small-scale desalination and industrial water remediation. Performance parameters for dehumidifier design for HDH, including a device-specific parallel-flow effectiveness, are explained. A new model for the performance of single bubble trays is developed based on the rapid mixing in the column and the approximation of negligible gas-side resistance. An experiment is performed to measure the heat transfer coefficients outside cooling coils in shallow bubble columns, in which geometric parameters including liquid height and cylinder diameter, height, and horizontal position relative to the sparger orifices are varied. The highest heat transfer coefficients are recorded on cylinders placed in the coalescing region and directly above the sparger orifices. Heat flux and parallel-flow effectiveness of a bubble column dehumidifier are investigated experimentally to validate the model, which predicts the heat transfer rate well with an average absolute error of <3%. The independence of heat flux and effectiveness from liquid depth supports the assumption of negligible gas-side resistance to heat and mass transfer. Despite the mass exchange, the bubble column dehumidifier performs like a typical heat exchanger: the heat flux decreases and effectiveness increases with increasing coil area. The results of this study enable modeling and design of bubble column dehumidifiers for high heat recovery and low capital cost.
by Emily Winona Tow.
S.M.
Moppett, Garry Dean. "Gas entrainment and mass transfer in a plunging jet bubble column". Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627169.
Pełny tekst źródłaQue, Fucheng. "Dynamic simulation of gas-liquid mixing in a two-dimensional bubble column". Thesis, University of Manchester, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281982.
Pełny tekst źródłaCloete, Jannean Christelle. "Oxygen transfer in a model hydrocarbon bioprocess in a bubble column reactor". Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96981.
Pełny tekst źródłaENGLISH ABSTRACT: The expansion of the global fuels industry has caused an increase in the quantity of hydrocarbons produced as a by-product of refinery gas-to-liquid processes. Conversion of hydrocarbons to higher value products is possible using bioprocesses, which are sustainable and environmentally benign. Due to the deficiency of oxygen in the alkane molecule, the supply of sufficient oxygen through aeration is a major obstacle for the optimization of hydrocarbon bioprocesses. While the oxygen solubility is increased in the presence of hydrocarbons, under certain process conditions, the enhanced solubility is outweighed by an increase in viscosity, causing a depression in overall volumetric oxygen transfer coefficient (KLa). The rate at which oxygen is transferred is defined in terms of a concentration driving force (oxygen solubility) and the overall volumetric oxygen transfer coefficient (KLa). The KLa term comprises an oxygen transfer coefficient (KL) and the gas-liquid interfacial area (a), which are dependent on the uid properties and system hydrodynamics. This behaviour is not well understood for hydrocarbon bioprocesses and in a bubble column reactor (BCR). To provide an understanding of oxygen transfer behaviour, a model hydrocarbon bioprocess was developed using a BCR with a porous sparger. To evaluate the interfacial area, the Sauter mean bubble diameter (D32) was measured using an image analysis algorithm and gas holdup (ϵG) was measured by the change in liquid height in the column. Together the D32 and ϵG were used in the calculation of interfacial area in the column. The KLa was evaluated with incorporation of the probe response lag, allowing more accurate representation of the KLa behaviour. The probe response lag was measured at all experimental conditions to ensure accuracy and reliability of data. The model hydrocarbon bioprocess employed C14-20 alkane-aqueous dispersions (2.5 - 20 vol% hydrocarbon) with suspended solids (0.5 - 6 g/l) at discrete super ficial gas velocity (uG) (1 - 3 cm/s). For systems with inert solids (corn our, dp = 13.36 m), the interfacial area and KLa were measured and the behaviour of KLa was described by separation of the in uences of interfacial area and oxygen transfer coefficient (KL). To further the understanding of oxygen transfer behaviour, non-viable yeast cells (dp = 5.059 m) were used as the dispersed solid phase and interfacial area behaviour was determined. This interfacial area behaviour was compared with the behaviour of systems with inert solids to understand the differences with change in solids type. In systems using inert solids, a linear relationship was found between G and uG. An empirical correlation fo rthe prediction of this behaviour showed an accuracy of 83.34% across the experimental range. The interfacial area showed a similar relationship with uG and the empirical correlation provided an accuracy of 78.8% for prediction across the experimental range. In inert solids dispersions, the KLa increased with uG as the result of an increase in interfacial area as well as increases in KL. An increase in solids loading indicated an initial increase in KLa, due to the in uence of liquid-film penetration on KL, followed by a decrease in KL at solids loading greater than 2.5 g/l, due to diffusion blocking effects. In systems with yeast dispersions, the presence of surfactant molecules in the media inhibited coalescence up to a yeast loading of about 3.5 g/l, and resulted in a decrease in D32. Above this yeast loading, the fine yeast particles increased the apparent viscosity of the dispersion sufficiently to overcome the in uence of surfactant and increase the D32. The behaviour of G in yeast dispersions was similar to that found with inert solids and demonstrated a linear increase with uG. However, in yeast dispersions, the interaction between alkane concentration and yeast loading caused a slight increase in dispersion viscosity and therefore G. An empirical correlation to predict G behaviour with increased uG was developed with an accuracy of 72.55% for the experimental range considered. Comparison of yeast and inert solids dispersions indicated a 37.5% lower G in yeast dispersions compared to inert solids as a result of the apparent viscosity introduced by finer solid particles. This G and D32 data resulted in a linear increase in interfacial area with uG with no significant in uence of alkane concentration and yeast loading. This interfacial area was on average 6.7% lower than interfacial area found in inert solid dispersions as a likely consequence of the apparent viscosity with finer particles. This study provides a fundamental understanding of the parameters which underpin oxygen transfer in a model hydrocarbon bioprocess BCR under discrete hydrodynamic conditions. This fundamental understanding provides a basis for further investigation of hydrocarbon bioprocesses and the prediction of KLa behaviour in these systems.
AFRIKAANSE OPSOMMING: Die uitbreiding van die internasionale brandstofbedryf het 'n toename veroorsaak in die hoeveelheid koolwaterstowwe geproduseer as 'n deur-produk van raffinadery gas-tot-vloeistof prosesse. Omskakeling van koolwaterstowwe na hoër waarde produkte is moontlik met behulp van bioprosesse, wat volhoubaar en omgewingsvriendelik is. As gevolg van die tekort aan suurstof in die alkaan molekule, is die verskaffing van voldoende suurstof deur deurlugting 'n groot uitdaging vir die optimalisering van koolwaterstof bioprosesse. Terwyl die suurstof oplosbaarheid verhoog in die teenwoordigheid van koolwaterstowwe, onder sekere proses voorwaardes is die verhoogde oplosbaarheid oortref deur 'n toename in viskositeit, wat 'n depressive veroorsaak in die algehele volumetriese suurstofoordragkoëffisiënt (KLa). Die suurstof oordrag tempo word gedefinieer in terme van 'n konsentrasie dryfkrag (suurstof oplosbaarheid) en KLa. Die KLa term behels 'n suurstofoordragkoëffisiënt (KL) en die gas-vloeistof oppervlakarea (a), wat afhanklik is van die vloeistof eienskappe en stelsel hidrodinamika. Hierdie gedrag is nie goed verstaan vir koolwaterstof bioprosesse nie, asook in kolom reaktors (BCR). Om 'n begrip van suurstof oordrag gedrag te voorsien, is 'n model koolwaterstof bioproses ontwikkel met 'n BCR met 'n poreuse besproeier. Om die oppervlakarea te evalueer, is die gemiddelde Sauter deursnit (D32) gemeet deur 'n foto-analise algoritme en gas vasvanging ( G) is gemeet deur die verandering in vloeibare hoogte in die kolom. Saam is die D32 en G gebruik in die berekening van die oppervlakarea in die kolom. Die KLa is geëvalueer met insluiting van die meter se reaksie sloering, om n meer akkurate voorstelling van die KLa gedrag te bereken. Die meter reaksie sloering was gemeet op alle eksperimentele toestande om die akkuraatheid en betroubaarheid van data te verseker. Die model koolwaterstof bioproses gebruik n-C14-20 alkaan-water dispersies (2.5 - 20 vol% koolwaterstof) solide partikels (0.5 - 6 g/l) op diskrete oppervlakkige gas snelhede (1 - 3 cm/s). Vir stelsels met inerte solides (koring meel, dp = 13.36 m), is die oppervlakarea en KLa gemeet en die gedrag van KLa beskryf deur skeiding van die invloede van oppervlakarea en KL. Om die begrip van suurstof oordrag se gedrag te bevorder, is nie-lewensvatbare gisselle (dp = 5.059 m) gebruik as die verspreide solide fase en oppervlakarea is bepaal. Hierdie oppervlakarea gedrag is vergelyk met die van stelsels met inerte solides om die verskille met verandering in solide tipes te verstaan. In stelsels met inerte solides, is 'n line^ere verwantskap gevind tussen G en uG. 'n Empiriese korrelasie vir die voorspelling van hierdie gedrag is opgestel met 'n akkuraatheid van 83.34% in die eksperimentele reeks. Die oppervlakarea het 'n soortgelyke verhouding met uG en die empiriese korrelasie verskaf 'n akkuraatheid van 78,8% vir die voorspelling van oppervlakarea oor die eksperimentele reeks. In inerte solide dispersies, het die KLa toegeneem met uG as die gevolg van 'n toename in grens oppervlak asook stygings in KL. 'n Toename in solides belading het n aanvanklike styging in KLa aangedui, as gevolg van die invloed van die vloeistof-film penetrasie op KL, gevolg deur 'n afname in KL op vastestowwe ladings groter as 2.5 g/l, te danke aan diffusie blokkeer effekte. In stelsels met gis dispersies, het die teenwoordigheid van benattings molekules in die media samesmelting geïnhibeer tot 'n gis lading van ongeveer 3.5 g/l, en het gelei tot 'n afname in D32. Bo hierdie gis lading, het die fyn gis partikels die skynbare viskositeit van die verspreiding verhoog genoegsaam om die invloed van benattings molekules te oorkom en die D32 te verhoog. Die gedrag van G in gis dispersies was soortgelyk aan die van inerte solides en dui op 'n lineêre toename met uG. Maar in gis dispersies, het die interaksie tussen alkaan konsentrasie en gis lading 'n effense toename veroorsaak in die verstrooiing viskositeit en dus in G. 'n Empiriese korrelasie is ontwikkel om G gedrag te voorspel en het 'n akkuraatheid van 72,55% vir die eksperimentele verskeidenheid beskou. Vergelyking van gis en inerte patrikel dispersies wys 'n 37.5% laer G in gis dispersies in vergelyking met inerte vaste stowwe as 'n gevolg van die skynbare viskositeit bekendgestel deur fyner vastestowwe partikels. Hierdie G en D32 data het gelei tot 'n linere toename in grens oppervlak met uG met geen beduidende invloed van alkaan konsentrasie en gis lading nie. Die oppervlakarea was gemiddeld 6.7% laer as oppervlakarea gevind in inerte partikel dispersies as 'n waarskynlike gevolg van die skynbare viskositeit met fyner partikels. Hierdie studie bied 'n fundamentele begrip van die veranderlikes wat die suurstof oordrag definieer in 'n model koolwaterstof bioproses BCR onder diskrete hidrodinamiese voorwaardes. Hierdie fundamentele begrip bied n basis vir verdere ondersoek van koolwaterstof bioprosesse en en die voorspelling van KLa gedrag in hierdie stelsels.
Riquelme-Diaz, Alberto. "Bubble size distribution measurement, modeling and control in a laboratory flotation column". Master's thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25480.
Pełny tekst źródłaLin, Tsao-Jen. "Pressure and temperature effects on bubble column and liquid-solid fluidized bed /". The Ohio State University, 1996. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487942182324157.
Pełny tekst źródłaManjo, Persis Yefon. "A fundamental approach to predicting mass transfer coefficients in bubble column reactors". Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9120.
Pełny tekst źródłaA bubble column reactor is a vertical cylindrical vessel used for gas-liquid reactions. Bubble Columns have several applications in industry due to certain obvious advantages such as high gas-liquid interfacial area, high heat and mass transfer rates, low maintenance requirements and operating costs. On the other hand, attempts at modelling and simulation are complicated by lack of understanding of hydrodynamics and mass transfer characteristics. This complicates design scale-up and industrial usage. Many studies and models have attempted to evolve understanding of the hydrodynamic complexity in Bubble Columns reactors. A closer look at these studies and models reveals a variety of solution methods for different systems (Frössling, 1938; Clift et al., 1978; Hughmark, 1967; Dutta, 2007; Ranz and Marshall, 1952; Benitez, 2009; Buwa et al., 2006; Suzzia et al., 2009; Wylock et al., 2011). Numerous correlations (Frössling, 1938; Clift et al., 1978; Hughmark, 1967; Dutta, 2007; Ranz and Marshall, 1952; Benitez, 2009; Buwa et al., 2006) exist but to date in literature, there is no general approach to determining accurate estimates of average mass transfer coefficient values. Good estimates of the average mass transfer coefficient will improve the predictive capacity of the associated models. Recent attempts at modelling micro-scale bubble-fluid interaction resulted in the Bubble Cell Model, BCM, (Coetzee et al., 2009) which simulates the velocity vector field around a single gas bubble in a flowing fluid stream using a Semi-Analytical model. The aim of the present study is to extend the BCM applications by integrating the mass balance into the framework to predict the average mass transfer coefficient in bubble columns. A nitrogen-water steady state system was simulated in an axisymmetric grid where mass transfer occurs between the gas and liquid.
Cartland-Glover, Gregory M. "Use of computational fluid dynamics in the design of bubble column reactors". Thesis, Aston University, 2002. http://publications.aston.ac.uk/9648/.
Pełny tekst źródłaXu, Wanjing. "Acid rock drainage remediation with Bear River clinoptilolite in a slurry bubble column". Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44625.
Pełny tekst źródłaZame, Kenneth Kofiga. "Carbon Capture Using The Microalgae Chlorella Vulgaris in a Packed Bubble Column Photobioreactor". Youngstown State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1288578577.
Pełny tekst źródłaStudley, Allison F. "Numerical Modeling of Air-Water Flows in Bubble Columns and Airlift Reactors". Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/36380.
Pełny tekst źródłaMaster of Science
Masood, Rao Muhammad Atif [Verfasser], i Antonio [Gutachter] Delgado. "A Numerical Analysis of Bubble Column Flows / Rao Muhammad Atif Masood ; Gutachter: Antonio Delgado". Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2016. http://d-nb.info/1121913288/34.
Pełny tekst źródłaTchowa, Medjiade Willy Baudelaire [Verfasser], i Adrian [Akademischer Betreuer] Schumpe. "Flow Regime Identification in a Bubble Column / Willy Baudelaire Tchowa Medjiade ; Betreuer: Adrian Schumpe". Braunschweig : Technische Universität Braunschweig, 2016. http://d-nb.info/1175818895/34.
Pełny tekst źródłaTang, Jing. "Comparison of Dairy Manure Anaerobic Digestion Performance in Gas-lift and Bubble Column Digesters". Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/46319.
Pełny tekst źródłaMaster of Science
Ziegenhein, Thomas, Dirk Lucas, Roland Rzehak i Eckhard Krepper. "Closure relations for CFD simulation of bubble columns". Helmholtz-Zentrum Dresden-Rossendorf, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-144231.
Pełny tekst źródłaCui, Zhe. "Hydrodynamics in a bubble column at elevated pressures and turbulence energy distribution in bubbling gas-liquid and gas-liquid-solid flow systems". Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1109956144.
Pełny tekst źródłaTitle from first page of PDF file. Document formatted into pages; contains xxiii, 187 p.; also includes graphics Includes bibliographical references (p. 179-187). Available online via OhioLINK's ETD Center
Lam, Steven S. B. Massachusetts Institute of Technology. "Development of a multi-stage bubble column dehumidifier for application in a hymidification dehumidification desalination system". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/75452.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 67).
The Center for Clean Water and Clean Energy at MIT and KFUPM have been developing many novel desalination systems. One of the new technologies originating from the Lienhard Research Laboratory is the Humidification Dehumidification desalination system, or HDH. In many ways HDH resembles the natural rain cycle for producing fresh water, in that sea water is evaporated from oceans into humid air that travels up into the atmosphere, before condensing and producing precipitation. That precipitation is then collected as fresh drinking water. One of the main hindrances with carrier gas based desalination systems over traditional thermal desalination systems like multi-flash distillation (MSF) systems is that there is a large thermal resistance in the dehumidifier between the carrier gas and the condensing coils resulting in poor heat transfer rates. The proposed solution is to create a bubble column for improved condensation. The condensing coil will be submerged in a body of water while humid air is sent through a sieve plate to create bubbles in this body of water where it will condense directly. Firstly, a single stage bubble column was designed, built, modeled, and tested. The model theoretically predicts the effects of bubble diameter, superficial velocity, liquid height in column, inlet mole fraction of vapor, impact on coils, and particle integration. Through experimentation it was shown that it was possible to achieve heat transfer rates of of 4 kW1m2 up to 20 kW1m2 ; rates that are 10 to 30 times that of existing state-of-the-art dehumidifiers. Secondly, a multi stage bubble column was designed, built, modeled, and tested in a full HDH system. Multi-staging is done to improve the effectiveness of the system. A three stage column was able to achieve an effectiveness of 89.4%.
by Steven Lam.
S.B.
Picardi, Robert N. "Numerical Analysis of Multiphase Flow in Bubble Columns and Applications for Microbial Fuel Cells". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/51689.
Pełny tekst źródłaMaster of Science
Ziegenhein, Thomas. "Fluid dynamics of bubbly flows". Helmholtz-Zentrum Dresden - Rossendorf, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-213581.
Pełny tekst źródłaAdetunji, Olubode Caleb. "Hybridization of electrical resistance tomography to population balance model for accurate bubble column reactor hydrodynamic parameter predictions". Doctoral thesis, University of Cape Town, 2016. http://hdl.handle.net/11427/22979.
Pełny tekst źródłaQazaq, Amjad Saleh Hussein Chemical Sciences & Engineering Faculty of Engineering UNSW. "Application of photocatalysis to the treatment of complex industrial aqueous effluent in a pilot-scale bubble column reactor". Awarded by:University of New South Wales. Chemical Sciences & Engineering, 2009. http://handle.unsw.edu.au/1959.4/44774.
Pełny tekst źródłaLefebvre, Jonathan [Verfasser]. "Three-phase CO2 methanation Methanation reaction kinetics and transient behavior of a slurry bubble column reactor / Jonathan Lefebvre". München : Verlag Dr. Hut, 2019. http://d-nb.info/1181515408/34.
Pełny tekst źródłaGoodall, Craig Michael. "The effects of flotation variables on the bubble size, mixing characteristics and froth behaviour in column flotation cells". Thesis, University of Cape Town, 1993. http://hdl.handle.net/11427/23802.
Pełny tekst źródłaSouzy, Nicolas. "Experimental study and improvement of mass transfer in vertical bubble columns". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10201/document.
Pełny tekst źródłaBubble column are involved in many industrial fields ranging from chemical industry to mineral processing. It recently became an industrial stake for the production of micro-algae intended for medicinal use, food or energy: the oxygen and carbon dioxide concentrations can be controlled via the efficient mass transfer induced by the significant gas-liquid interfaciale area into the bubble column. Firstly, experimental closed-loop study has been carried out to simulate the passage of gas in a succession of columns in series. The associated theoretical model confirms the critical importance of the bubble diameter for mass transfer.Therefore, an innovative Micro-Bubble Generator (MBG) has been designed and tested. The prototype is able to produce micro-bubbles of average diameter Dbubble = 0.252 mm. The invention has been officially declared. The last chapter aims at improving data treatment methods for Planar Laser-Induced Fluorescence (PLIF), which enables to obtain experimentally mass transfer coefficient kl through concentration measurements. The first presented correction takes into account variations of the fluorescence extinction due to pH during the calibration step, and has been evaluated on CO2 concentration measurement in the wake of a free rising bubble. The second proposed correction should be applied when the length in the measurement region over which pH variations are observed increases: variations of the extinction coefficient will affect the local incident light intensity and therefore the measurements. The need for this correction has been illustrated on a test case in the wake of a cloud of free rising bubbles