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Microstructure and particle-laden flow in diesel particulate filterYamashita, Hiroshi, Satake, Shingo, Yamamoto, Kazuhiro 02 1900 (has links)
No description available.
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A study of gas lift on oil/water flow in vertical risersBrini Ahmed, Salem Kalifa 01 1900 (has links)
Gas lift is a means of enhancing oil recovery from hydrocarbon reservoirs. Gas
injected at the production riser base reduces the gravity component of the
pressure drop and thereby, increases the supply of oil from the reservoir. Also,
gas injection at the base of a riser helps to mitigate slugging and thus,
improving the performance of the topside facility. In order to improve the
efficiency of the gas lifting technique, a good understanding of the
characteristics of gas-liquid multiphase flow in vertical pipes is very important.
In this study, experiments of gas/liquid (air/water) two-phase flows, liquid/liquid
of oil/water two-phase flows and gas/liquid/liquid (air/oil/water) three-phase
flows were conducted in a 10.5 m high 52 mm ID vertical riser. These
experiments were performed at liquid and gas superficial velocities ranging from
0.25 to 2 m/s and ~0.1 to ~6.30 m/s, respectively. Dielectric oil and tap water
were used as test fluids. Instruments such as Coriolis mass flow meter, single
beam gamma densitometer and wire-mesh sensor (WMS) were employed for
investigating the flow characteristics. For the experiments of gas/liquid
(air/water) two-phase flow, flow patterns of Bubbly, slug, churn flow regimes and
transition regions were identified under the experimental conditions. Also, for
flow pattern identification and void fraction measurements, the capacitance
WMS results are consistent with those obtained simultaneously by the gamma
densitometer. Generally, the total pressure gradient along the vertical riser has
shown a significant decrease as the injected gas superficial velocity increased.
In addition, the rate of decrease in total pressure gradient at the lower injected
gas superficial velocities was found to be higher than that for higher gas
superficial velocities. The frictional pressure gradient was also found to increase
as the injected gas superficial velocity increased.
For oil-water experiments, mixture density and total pressure gradient across
the riser were found to increase with increasing water cut (ranging between 0 -
100%) and/or mixture superficial velocity. Phase slip between the oil and water
was calculated and found to be significant at lower throughputs of 0.25 and 0.5
m/s. The phase inversion point always takes place at a point of input water cut
of 42% when the experiments started from pure oil to water, and at an input
water cut of 45% when the experiment’s route started from water to pure oil.
The phase inversion point was accompanied by a peak increase of pressure
gradient, particularly at higher oil-water mixture superficial velocities of 1, 1.5
and 2 m/s.
The effects of air injection rates on the fluid flow characteristics were studied by
emphasizing the total pressure gradient behaviour and identifying the flow
pattern by analysing the output signals from gamma and WMS in air/oil/water
experiments. Generally, riser base gas injection does not affect the water cut at
the phase inversion point. However, a slight shift forward for the identified
phase inversion point was found at highest flow rates of injected gas where the
flow patterns were indicated as churn to annular flow. In terms of pressure
gradient, the gas lifting efficiency (lowering pressure gradient) shows greater
improvement after the phase inversion point (higher water cuts) than before and
also at the inversion point.
Also, it was found that the measured mean void fraction reaches its lowest
value at the phase inversion point. These void fraction results were found to be
consistent with previously published results.
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Microbial enhanced oil recovery : a pore-scale investigation of interfacial interactionsArmstrong, Ryan T. 06 January 2012 (has links)
Current oil production technologies recover only about one‐third to one‐half of the oil
originally present in an oil reservoir. Given current oil prices, even a modest increase in oil recovery efficiency is fiscally attractive. One novel approach to increase oil recovery
efficiency is a process called microbial enhanced oil recovery (MEOR), where microorganisms
are either used as a clogging agent to redirect flow or to produce biosurfactant that reduces
interfacial tension. This dissertation aims to understand the MEOR pore‐scale mechanisms
relevant to oil recovery by taking a two‐fold approach where transparent 2‐dimensional
micromodel experiments imaged with stereo microscopy and 3‐dimensional column
experiments imaged with x‐ray computed microtomography (CMT) are utilized. Micromodel
experiments allow for direct visualization of the biological phase (i.e. biofilm), however, only 2‐dimensional information is provided. Conversely, CMT experiments provide 3‐dimensional
pore‐scale information, but lack the ability to image the biological phase. With this two‐fold
approach, it is possible to distinguish multiple fluid interfaces, quantify fluid phase
saturations, measure oil blob size distributions, and visualize the biological phase.
Furthermore, a method to measure interfacial curvature from 3‐dimensional images is
developed, providing researchers a new perspective from which to study multiphase flow
experiments. Overall, the presented research utilizes pore‐scale imaging techniques to study
the interfacial interactions occurring during MEOR in an effort to better explain the physics,
and thus, increase the efficacy of MEOR. / Graduation date: 2012
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Slug flow induced corrosion studies using electrochemical noise measurementsDeva, Yashika Poorvi. January 1995 (has links)
Thesis (M.S.)--Ohio University, August, 1995. / Title from PDF t.p.
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Evaluation of vertical multiphase flow correlations for Saudi Arabian field conditionsAl-Muraikhi, Ahmed J. January 1989 (has links) (PDF)
Thesis (M.S.)--King Fahd University of Petroleum and Minerals, 1989. / Title from document title page. Includes bibliographical references. Available in PDF format via the World Wide Web.
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Iteratively coupled reservoir simulation for multiphase flow in porous mediaLu, Bo, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.
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Modelling of flow through porous packing elements of a CO2 absorption towerRautenbach, Christo 12 1900 (has links)
Thesis (MSc (Mathematics))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Packed beds are widely used in industry to improve the total contact area between two
substances in a multiphase process. The process typically involves forced convection of
liquid or gas through either structured or dumped solid packings. Applications of such
multiphase processes include mass transfer to catalyst particles forming the packed bed and
the adsorption of gases or liquids on the solid packing.
An experimental study on the determination of air flow pressure drops over different
packingmaterialswas carried out at the Telemark University College in Porsgrunn,Norway.
The packed bed consisted of a cylindrical column of diameter 0.072m and height 1.5m, filled
with different packingmaterials. Air was pumped vertically upwards through a porous distributor
to allow for a uniform inlet pressure. Resulting pressure values were measured at
regular height intervals within the bed. Due to the geometric nature of a Raschig ring packing
wall effects, namely the combined effects of extra wall shear stress due to the column
surface and channelling due to packing adjacent to a solid column surface, were assumed to
be negligible.
Several mathematical drag models exist for packed beds of granular particles and an
important question arises as to whether they can be generalized in a scientific manner to
enhance the accuracy of predicting the drag for different kinds of packing materials. Problems
with the frequently used Ergun equation, which is based on a tubular model for flow
between granules and then being empirically adjusted, will be discussed. Some theoretical
models that improve on the Ergun equation and their correlation with experimental work
will be discussed. It is shown that a particular pore-scale model, that allows for different geometries
and porosities, is superior to the Ergun equation in its predictions. Also important
in the advanced models is the fact that it could take into account anomalies such as dead
zones where no fluid transport is present and surfaces that do neither contribute to shear
stress nor to interstitial form drag. The overall conclusion is that proper modelling of the
dynamical situation present in the packing can provide drag models that can be used with
confidence in a variety of packed bed applications. / AFRIKAANSE OPSOMMING: Gepakte materiaal strukture word in die industrie gebruik om die kontak area tussen twee
stowwe in meervoudige faseprosesse te vergroot. Die proses gaan gewoonlik gepaard met
geforseerde konveksie van ’n vloeistof of ’n gas deur gestruktureerde of lukrake soliede
gepakte strukture. Toepassings van sulke meervoudige faseprossese sluit onder andere in
die massa-oordrag na katalisator partikels wat die gepakte struktuur vorm of die absorpsie
van gasse of vloeistowwe op die soliede gepakte elemente.
’n Eksperimentele ondersoek oor die drukval van veskillende gepakte elemente in ’n
kolom is gedoen by die Telemark University College in Porsgrunn, Noorweë. Die gepakte
struktuur het bestaan uit ’n kolommet ’n diameter van 0.072m en ’n hoogte van 1.5m. Lug is
vertikaal opwaarts gepomp deur ’n poreuse plaat wat gesorg het vir ’n benaderde uniforme
snelheidsprofiel. Die druk is toe op intervalle deur die poreuse struktuur gemeet. In die
studie is die effekte van die eksterne wande, nl. die bydrae van die wand se wrywing en die
vorming van kanale langs die kolom wand, as weglaatbaar aanvaar.
Daar bestaan baie wiskundige dempingsmodelle vir gepakte strukture wat uit korrels
saamgestel is. ’n Belangrike vraag kan dus gevra word, of laasgenoemde modelle veralgemeen
kan word op ’n wetenskaplike manier om die demping deur verskillende gepakte
strukture akkuraat te kan voorspel. Probleme wat ontstaan het met die wel bekende Ergun
vergelyking, wat gebaseer is op ’n kapillêre model en wat toe verder aangepas is deur empiriese
resultate van uniforme sfere, sal bespreek word. Teoretiesemodelle wat verbeteringe
op die Ergun vergelyking voorstel sal bespreek word en vergelyk word met eksperimentele
data. Daar word ook gewys dat ’n spesifieke porie-skaal model, wat aanpasbaar is vir verskillende
geometrieë en porositeite, in baie gevalle beter is as die Ergun vergelyking. ’n
Ander baie belangrike aspek van gevorderde modelle is die moontlikheid om stagnante gebiede
in die gepakte strukture in ag te neem. Laasgenoemde gebiede sal die totale kontak
area sowel as die intermediêre vorm demping verlaag. Die gevolgtrekking is dat wanneer
deeglike modulering van dinamiese situasies in die industrie gedoen word kan dempings
modelle met vertroue op ’n verskeidenheid gepakte strukture toegepas word.
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Detecção de escoamento envolvendo gás e petróleo empregando técnicas de monitoramento baseadas em radiação infravermelhaDutra, Guilherme 11 December 2013 (has links)
Na região do espectro visível o petróleo é opaco, porém na região do infravermelho o petróleo apresenta translucidez à radiação. Isto permite a detecção óptica e não intrusiva de fenômenos que ocorram com o petróleo e no interior do volume contendo petróleo. É então explorada a região de 8 a 12 μm mostrando resultados que comprovam o potencial da técnica. A detecção óptica baseia-se na Lei de Beer-Lambert: o espectro eletromagnético emitido por fonte óptica, ao atravessar meio absorvedor, sofre decaimento exponencial na intensidade correspondente ao caminho óptico percorrido, à concentração da substância e ao seu coeficiente de absorção. Porém, em certos casos, outros efeitos ópticos, como a reflexão e a refração predominam, gerando resultados que não são compreendidos somente pelo estudo da absorção. Para compreender tais resultados é implementado modelo matemático do escoamento de bolhas de ar em petróleo. Ao utilizar radiação infravermelha para detecção óptica trabalha-se no liminar entre o domínio óptico e o térmico. Para entendimento dos limites de cada efeito é realizado estudo da influência da variação de temperatura na detecção óptica do petróleo. Tendo todo o sistema óptico caracterizado, são realizados testes com o escoamento de bolhas de ar em petróleo e desenvolvido o circuito fechado para o escoamento bifásico envolvendo petróleo e ar. É observado o escoamento de bolhas em cuveta com 12 mm de comprimento de interação. Como os resultados foram obtidos sem a utilização de materiais otimizados para o comprimento de onda de trabalho, conclui-se ser possível transmissão por caminhos mais longos. Como conclusão, é possível detectar de forma não intrusiva o escoamento bifásico envolvendo petróleo e ar empregando técnicas de monitoramento baseadas em radiação infravermelha. Os resultados são promissores e devem resultar no desenvolvimento de instrumentação com potencial para aplicação em campo para a caracterização de escoamento envolvendo petróleo e outras substâncias como água, CO2, H2S, gás natural entre outros. / Petroleum is opaque in the visible region of the electromagnetic spectrum and therefore is normally a common sense that optical techniques cannot be used as a noninvasive tool to monitor any physical or chemical phenomena through a petroleum volume. There is, however, a great opportunity when the infrared region of the petroleum optical absorption spectrum given that it is semitransparent and therefore radiation can propagate through a volume containing petroleum or mixture with petroleum. The optical detection is based on the Beer-Lambert Law: the electromagnetic spectrum emitted by an optical source, crossing through the absorber undergoes exponential decay in intensity corresponding to the optical path, the concentration of the substance and its absorption coefficient. However, in certain cases, other optical effects such as reflection and refraction predominate, leading to light attenuation that is not understood only by the study of absorption. To understand these results it is implemented a mathematical model of the air bubbles flowing inside a petroleum volume. It is worth pointing out that the IR region of the electromagnetic spectrum can be understood via optical as well as thermal phenomena. To understand the limits of each effect a study of the influence of the temperature variation on the optical detection of petroleum is performed. The flow of air bubbles in static petroleum is studied and a flow loop for air and oil is designed and tested and the flow is measured by the IR monitoring system. The flow of bubbles is observed through 12 mm length of petroleum. These results were obtained without using optimized components and it is concluded that transmission through longer paths is possible. In conclusion, it is possible to detect, by a non -intrusive technique, the two-phase flow involving the petroleum and air employing monitoring techniques based on infrared radiation. The results are promising and should result in the development of instrumentation for potential application in the field for characterizing flow involving petroleum and other substances such as water, CO2, H2S, natural gas and others.
Keywords (letras minúsculas separadas por vírgulas): infrared, petroleum, CO2, multiphase flow.
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Contribution à l’étude de l’atomisation assistée d’un liquide : instabilité de cisaillement et génération du spray / Assisted atomisation of a liquid layer : case of thin filmsMarty, Sylvain 27 April 2015 (has links)
L’atomisation assistée est un procédé de formation d’un spray de gouttelettes issu d’une nappe liquide sous l’action d’un courant gazeux à forte vitesse dans un injecteur. Ce procédé est très utilisé dans de nombreuses applications industrielles. Nous étudions la succession d’instabilités hydrodynamiques qui génère les gouttes du spray à l’aide d’une méthode LIF pour mesurer la fréquence des vagues et d’une sonde optique pour la granulométrie des gouttes. Nous validons expérimentalement un nouveau modèle de stabilité linéaire inviscide pour l’instabilité de cisaillement, intégrant un profil de vitesse avec déficit à l’injection. Des simulations numériques et un modèle spatio-temporel de stabilité linéaire sont utilisés pour mettre en avant de nouveaux mécanismes de déstabilisation, de croissance des vagues et de création de gouttes. Les lois d’échelles connues prédictives du diamètre moyen des gouttes en fonction du Weber gaz sont testées pour de nouvelles variables d’étude. / Assisted atomization is a process used to form a spray of droplets. A slow liquid phase is strippedby the action of a strong gas current in order to generate the spray. This process is used in manyindustrial applications. We study the succession of hydrodynamic instabilities generating dropletsby means of a LIF method to measure the frequency and growthrate of waves, and with an opticalprobe to measure drop size and velocity. We validate experimentally a model including an interfacialvelocity deficit in the inviscid stability analysis. Experiments are compared to numerical simulationsand spatiotemporal stability analysis results : the confrontation of these three approaches is used tobring forward new mechanisms of destabilization, growth of waves and creation of drops. We assessthe influence of liquid thickness and dynamic pressure ratio on the dependency of the mean dropletdiameter with the Weber number.
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Estudo teórico e experimental de um reator anaeróbio de fluxo ascendente e manta de lodo tratando águas residuárias domésticas.LIMA, Maria Gorethe de Sousa. 05 October 2018 (has links)
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Previous issue date: 2008-05-29 / CNPq / O trabalho de tese em questão teve por objetivo geral realizar um estudo teórico/experimental para avaliar a fluidodinâmica de um reator anaeróbio de fluxo ascendente e manta de lodo (Upflow Anaerobic Sludge Blanket – UASB), tratando água residuária doméstica, visando contribuir para melhorar o desempenho dos dispositivos de separação de fases. Para o estudo experimental, foi realizado o monitoramento da estabilidade operacional e da eficiência de tratamento do reator por meio de análises físico – químicas de amostras do seu afluente e efluente e das pressões ao longo do reator. Os resultados obtidos experimentalmente constataram que o reator apresentava uma boa estabilidade operacional. A eficiência de remoção de matéria orgânica foi considerada baixa (42 %); enquanto que para os sólidos totais em suspensão a eficiência de remoção variou em torno 70 %. Os valores de pressão apresentaram uma relação linear decrescente à medida que a tomada de pressão se distanciava da zona de digestão. Para o estudo numérico, foram desenvolvidas malhas no espaço bi e tridimensional representativas do reator UASB modificando as disposições e inclinações do defletor de gases. Diferentes simulações foram realizadas usando o Ansys CFX 10.0 para diferentes fluxos. Os resultados numéricos constataram que a disposição e inclinação do defletor de gases além de exercer grande influência sobre a distribuição de velocidades no reator, também afetou consideravelmente o desempenho dos dispositivos de separação de fases (defletor de gases e separador trifásico). Com relação ao fluxo mássico, foi verificado que o mesmo apresentou uma relação diretamente proporcional com a eficiência de retenção de sólidos suspensos, para a faixa estudada no presente trabalho (10-4 a 0,11 kg/s). A análise comparativa dos resultados numéricos e experimentais da pressão e da concentração de lodo na saída do reator com inclinação do defletor voltada para cima apresentaram diferenças da ordem de 2 kPa e de 10 mg/L, respectivamente, sendo consideradas satisfatórias. / The thesis work in question had for general objective to accomplish a theoretical/experimental study to evaluate the fluid dynamic of an anaerobic reactor of ascending flow and sludge blanket (Upflow Anaerobic Sludge Blanket – UASB), treating domestic wastewater, seeking to contribute to improve the performance of the phases separation devices. For the experimental study, it was accomplished the monitorially of the operational stability and the efficiency of the reactor treatment through physical-chemical analyses from samples of its affluent and effluent, as well as, the pressure along the reactor. The results obtained experimentally proved that the reactor presented a good operational stability. The efficiency of removal organic matter was considered low (42%); while for the total solid in suspension the removal efficiency varied around 70%. The pressure values presented a decreasing linear relationship as the taken of pressure distanced itself of the digestion zone. For the numeric study, meshes were developed in the space bi and three-dimensional representative of the UASB reactor modifying the dispositions and inclinations of the reflector of gases. Different simulations were accomplished using the Ansys CFX 10.0 for different flows. The numeric results verified that the disposition and inclination of the gases diverter besides exercising great influence on the distribuition of speed in the reactor, they also affected considerably the acting of the devices of phases separation (gases diverter and three-phase separator). In relation to the mass flow, it was verified that the same one presented a relationship directly proportional with the efficiency of suspended solid retention, for the strip studied in the
present work (10-4 to 0,11 kg/s). The comparative analysis of the numeric and experimental results of the pression and of the sludge concentration in the exit of the reator with inclination of the diverter returned upward they presented differences of the order of 2 kPa and of 10 mg/L, respectively, being considered satisfactory.
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