Une méthodologie pour mesurer la perméabilité plane d’un milieu fibreux par un flux d’air transitoire est développée. Le procédé, basé sur la mesure de pression d’un gaz aux bornes du système, au cours d’un écoulement transitoire, est pratique, propre et rapide, et permet d'éviter l'utilisation d'un débitmètre de gaz et offre la possibilité d'étudier le transport d’un gaz à l'intérieur du milieu fibreux.Le transport du gaz dans un milieu poreux fibreux est décrit par plusieurs modèles suivant les différents régimes d'écoulement. La perméabilité, dépendant uniquement de l’architecture fibreuse, est déterminée par une méthode inverse, en ajustant les résultats de la simulation aux données expérimentales obtenues par une hausse ou une chute de la pression. Les résultats pour la perméabilité visqueuse Kv des tissus sergés des verre/carbone (Kv allant de 10-11 à 10-10 m2) mesurée à l'aide d’un gaz corrèlent bien à la perméabilité mesurée avec des techniques d'injection ou compression utilisant un liquide. L'écart avec la loi de Darcy causé par le glissement du gaz sur les tissus à faible perméabilité (tissus unidirectionnels de carbone: Kv de 10-14 à 10-12 m2) est analysé et un paramètre lié au tissu montre une dépendance avec la perméabilité, avec une tendance similaire au paramètre de Klinkenberg utilisé pour les sols et les roches.Les erreurs expérimentales dues à des dimensions, à l’effet thermique, à la variation de pression, à la manipulation des échantillons, et à du gaz emprisonné sur les bords sont analysés. Il en ressort que la sensibilité des capteurs de pression et des volumes de gaz piégés sur les bords sont les facteurs les plus importants.La mise en place d’une méthode permettant une mesure directe de la perméabilité à l’aide d’un gaz du tenseur 2D de perméabilité est proposée pour les problèmes de gaz piégés sur les bords. Les expériences simulées montrent que les mesures basées sur la pression mesurée à trois positions pourraient fournir des résultats fiables et précis pour des tissus avec des rapports d’anisotropie perméabilité (K1/K2) allant de 0,1 à 10, et avec des orientations principales quelconques. / A methodology to measure in-plane permeability of fibrous media using a transient one dimensional air flow is developed. The method, based on the measurement of gas pressure at the boundaries throughout the transient flow, is convenient, clean and fast, avoids usage of a gas flow meter and offers a way to study the gas transport within fibrous media. The gas transport through fibrous porous media is described by several models to comply with different flow regimes. The permeability, only depending on the fibrous structure, is determined by inverse method, fitting the simulation results to the experimental data obtained using rising or dropping pressure methods. The results of viscous permeability Kv of Glass/Carbon Twill Woven fabrics (viscous permeability Kv ranging from 10-11 to 10-10 m2) measured using gas match well the permeability measured with liquid compression and injection techniques from previous works. The deviation from Darcy's law caused by gas sliding effect on low permeability Carbon Uni-Directional fabrics (Kv from 10-14 to 10-12 m2) is analyzed and a related parameter of fabric material shows a dependence in permeability, with a similar trend as the Klinkenberg sliding parameter in soils and rocks.The experimental errors due to dimensions, thermal effect, pressure variation, sample handling, and trapped gas at boundaries are analyzed. It comes out that the sensitivities of pressure sensors and trapped gas volumes at the boundaries have the most important effects. A design for 2D measurement using gas to obtain 2D permeability tensor in one single test is proposed to avoid the issues of trapped gas at boundaries. Simulated experiments show that the measurements based on pressure measured at three proposed locations could provide robust and accurate results for fabrics of anisotropic permeability ratios (K1/K2) ranging from 0.1 to 10, with various principal permeability direction orientations.

Ce manuscrit présente l'étude et l'analyse d'écoulements de gaz raréfiés, induits par la transpiration thermique. Le terme de transpiration thermique désigne le mouvement macroscopique d'un gaz raréfié engendré par l'effet du seul gradient de température. L'aspect principal de ce travail est centré autour de la mesure du débit stationnaire déclenché en soumettant un micro tube à un gradient de température appliqué le long de son axe. On a développé à cet effet un appareillage expérimental original ainsi qu'une méthodologie expérimentale innovatrice basée sur la dépendance du phénomène, analysé dans son ensemble, à l'égard du temps. Les résultats obtenus pour le débit stationnaire initial de transpiration thermique et pour les paramètres thermo-moléculaires caractérisant l'équilibre final de débit nul, ont été comparés aux résultats obtenus numériquement par la résolution de l'équation cinétique modèle de Shakhov et par la méthode de simulation directe de Monte-Carlo. / This thesis presents the study and analysis of rarefied gas flows induced by thermal transpiration. Thermal transpiration refers to the macroscopic movement of rarefied gas generated by a temperature gradient. The main aspect of this work is centered around the measurement of the mass flow rate engendered by subjecting a micro-tube to a temperature gradient along its axis. In this respect, an original experimental apparatus and an original time-dependent experimental methodology was developed. The experimental results for the initial stationary thermal transpiration mass flow rate and for the final zero- flow thermal molecular parameters were compared with the results obtained from the numerical solution of the Shakhov model kinetic equation and the direct simulation Monte Carlo method.

O trabalho aborda a aplicação da técnica de reconciliação de dados para o balanço da movimentação de gás natural em uma malha de escoamento de gás não processado, elaborando também um método de cálculo rápido de inventário de um duto. Foram aplicadas, separadamente, a reconciliação volumétrica à condição padrão de medição e a reconciliação mássica, bem como realizadas comparações dos resultados em relação ao balanço original e verificação do balanço resultante de energia em termos de poder calorífico superior. Dois conjuntos de pesos foram aplicados, um arbitrado de acordo com o conhecimento prévio da qualidade do sistema de medição de cada um dos pontos, outro baseado no inverso da variância dos volumes diários apurados no período. Ambos apresentaram bons resultados e o segundo foi considerado o mais apropriado. Por meio de uma abordagem termodinâmica, foi avaliado o potencial impacto, ao balanço, da condensação de parte da fase gás ao longo do escoamento e a injeção de um condensado de gás natural não estabilizado por uma das fontes. Ambos tendem a impactar o balanço, sendo o resultado esperado um menor volume, massa e energia de fase gás na saída. Outros fatores de considerável impacto na qualidade dos dados e no resultado final da reconciliação são a qualidade da medição de saída do sistema e a representatividade da composição do gás neste ponto. O inventário é calculado a partir de uma regressão que se baseia em um regime permanente de escoamento, o que pode apresentar maior desvio quando fortes transientes estão ocorrendo no último dia do mês, porém a variação de inventário ao longo do mês possui baixo impacto no balanço. Concluiu-se que a reconciliação volumétrica é a mais apropriada para este sistema, pois os dados reconciliados levam os balanços mássicos e de energia em termos de poder calorífico, ambos na fase gás, para dentro do perfil esperado de comportamento. Embora um balanço volumétrico nulo apenas da fase gás não seja por si só o comportamento esperado quando se considera os efeitos descritos, para desenvolver um balanço mais robusto é necessário considerar as frações líquidas presentes no sistema, agregando maior dificuldade na aquisição e qualidade dos dados. / This purpose of this study is the application of data reconciliation to the balancing of a wet natural gas network and to develop a quick approach to calculate the gas linepack. Volumetric reconciliation, measured at standard conditions, and mass reconciliation were applied separately, the results were compared to the original balance and the energy balance in terms of gross calorific value was verified. Two sets of weights have been applied, one arbitrated according to the previous knowledge on the quality of the measurement system of each point, another based on the inverse of the variance of the daily volumes in the period. Both showed good results and the second was considered the most appropriate because of its adherence to the literature. Through a thermodynamic approach, the potential impact on the balance of the condensation of the gas phase along the flow and the injection of a not stabilized gas condensate by one of the sources have been evaluated. Both tend to impact the balance, resulting in smaller volume, mass and energy in the gas phase output. Others factors of significant impact in data quality and in the reconciliation results are the quality of the outlet flow measurement and the representativeness of the gas composition at this point. The linepack is calculated from a regression that relies on a steady flow approach, which can present a higher deviation when strong transients are taking place in that period, but the linepack variation over the month has showed low impact on the balance. The study concludes that the volumetric reconciliation is the most suitable for this system, as reconciled data lead the mass and energy balances, both in the gas phase, into the expected pattern of behavior, according to the thermodynamic evaluation. Although a volume balance reaching zero for the gas phase is not the expected behavior when taking into account the effects described, developing a more robust balance would demand to consider the liquid fractions present in the system, which may add more difficulty in the data acquisition and in guarantying its quality.

The program COMSOL Multiphysics was used to simulate a flow of helium gas transporting ionized fission products out of an ion guide. Two important parameters to study from the simulation was the evacuation time and velocity of the ions. The mean evacuation time was shown to be 0.1173s, and the velocity of a single particle peaked at 2500m/s, 1000-1500m/s being more common.

The new millennium has seen revolutionary advances in photonsource technology. As the newly constructed synchrotron facilityMAX IV in Lund, Sweden, pushes brilliance toward what isphysically possible, low-yield spectroscopic techniques, such asresonant inelastic X-ray scattering (RIXS), open new doors inmolecular and condensed matter research. The VERITAS beamline atMAX IV is designed for high-resolution vibrational RIXS on gases.X-rays interact with flowing molecules inside a window-cappedcell, but the radiation intensity is expected to be large enoughto damage the windows, and cause build-up of photochemicalproducts, which lowers transmission. To address these issues, anovel gas cell design is presented, wherein the distance betweensample gas and window is increased by using a flowing heliumbuffer. The main challenge is maintaining a steep sample gasconcentration gradient within the cell, and to that end, gas flowswere simulated on various geometries by using the finite elementmethod to solve the Navier-Stokes equations. Results were used toconstruct a prototype, and confocal Raman microscopy was used forconcentration characterization. Preliminary measurements revealeda uniform sample gas distribution, and the technique proved to beinefficient for wide scanning of parameter values. This suggeststhat a supplementary experiment is required to find roughestimates of good parameter values, which can then be followed upwith new Raman measurements for fine-tuning of the properparameter space. Real-time visualization of the sample gas flow,using a visible gas under an optical microscope, is one candidatefor this supplementary experiment.

During operation of heavy ion accelerators a significant pressure rise has been observed when the intensity of the high energy beam was increased. The cause for this pressure rise is ion induced desorption, which is the result when beam ions collide with residual gas molecules in the accelerator, whereby they undergo charge exchange. Since the change in charge state will affect the bending radius of the particles after they have passed a bending magnet, they will not follow the required trajectory but instead collide with the vacuum chamber wall and gas are released. For the Future GSI project FAIR (Facility for Antiproton and Ion Research) there is a need to upgrade the SIS18 synchrotron in order to meet the requirements of the increased intensity. The aim of this work was to measure the desorption yields, η, (released molecules per incident ion) from materials commonly used in accelerators: 316LN stainless steel, Cu, Etched Cu, gold coated Cu, Ta and TiZrV coated stainless steel with argon and uranium beams at the energies 5-100 MeV/u. The measurements were performed at GSI and at The Svedberg Laboratory where a new dedicated teststand was built. It was found that the desorption yield scales with the electronic energy loss to the second power, decreasing for increasing impact energy above the Bragg Maximum. A feasibility study on the possibility to use laser refractometry to improve the accuracy of a specific throughput system was performed. The result was an improvement by up to 3 orders of magnitude, depending on pressure range.

The aim of the current study is to model (non-wetting) liquid flow in a packed bed under the influence of gas flow. It has been observed experimentally that non-wetting liquid flows in a packed bed in form of small droplets and rivulets falling through the void regions. Continuum models have not been successful in predicting liquid flow paths when the liquid is injected through a point source in the packed bed. In the current study, we present a discrete deterministic model for modeling the liquid flow in a packed bed, under the influence of gas flow. When a high velocity gas blast in injected into a dry packed bed, a cavity or a void is formed in front of the nozzle. The cavity size increases with increasing gas velocity and exhibits hystersis in size upon increasing and decreasing gas flow rate. The cavity size is very important in determining the gas penetration into the packed bed. A proper gas flow profile prediction is necessary for determining it’s effect on the liquid flow behavior. Attempts at modeling cavity sizes have mostly been confined to experimental studies and development of correlations. Different correlations show different dependence on operating as well as bed parameters and a fundamental understanding of the cavity formation and hystersis phenomena is missing. We adopt a combined Eulerean-Lagrangian approach to study the above mentioned phenomena mathematically. Gas is modeled as a continua and solid as discrete (soft sphere D.E.M. approach). Hystersis and cavity formation studies are carried out in a 2D-slot rectangular packed bed. A discrete deterministic liquid flow model (developed and validated under structured packing conditions using x-ray radiography flow visualization technique), is used to study the effect of presence of liquid on the dry bed void size, when liquid is injected in a packed bed through a point source. It is found that the gas pushes the liquid away from the nozzle side wall. Also, the cavity sizes during gas velocity decreasing case are found to be larger in size than the void size obtained during velocity increasing case for the same inlet gas flow rate. This difference is void size leads to more gas penetration into the bed and thus more liquid shift away from the nozzle side wall. Presence of liquid is found to affect the void size (compared to dry bed size) negligibly.

No Brasil, se espera ter até 2014, de acordo com o prazo da Política Nacional de Resíduos Sólidos, todos os lixões erradicados e os resíduos sólidos urbanos gerados depositados em aterros sanitários. Atualmente, os projetos de aterros sanitários dão oportunidade para um nicho de mercado, o da fonte de geração de energia. Um parâmetro de controle da poluição do ar causada pelos aterros sanitários são as chamadas camadas de cobertura. Nesse contexto, é de fundamental importância o estudo de camadas de cobertura de resíduos por ser um importante elemento de projeto para evitar ou minimizar a poluição do ar devido aos gases gerados em aterros sanitários de resíduos sólidos, já que é o elo existente entre o ambiente interno dos resíduos e a atmosfera. A presente pesquisa aborda o comportamento dos gases em relação à camada de cobertura existentes na CTR de Nova Iguaçu e no Lixão remediado de Seropédica. Foram realizados ensaios de Placa de Fluxo, medição de pressão e concentração dos gases no contato solo-resíduo e emissões dos gases pelos drenos, além das análises de solo in situ e em laboratório. Os ensaios foram realizados de outubro a novembro de 2012. Os resultados indicaram uma inexistência de fluxo de gases pela camada de cobertura, que possui 1,10 m de espessura, do lixão de Seropédica, sendo encontrado apenas fluxo nos drenos. Na CTR Nova Iguaçu, foi verificada que praticamente a inexistência de fluxo de gases com o sistema de gás ligado, mesmo possuindo uma camada de cobertura de 0,8 m. / In Brazil, according to the timeframe given by the National Policy of Solid Waste, by 2014, every dump will be eradicated and every municipal solid waste generated will be deposited in landfills. Currently, the landfill projects provide an opportunity for the market, which is a source of energy. A parameter of control of the air pollution caused by landfills is called cover layers. In this context, it is important the study of the cover layers to avoid or minimized the air pollution due to gases generated in landfills, which is the link between the solid waste and the atmosphere. This research addresses the behavior of the gases in relation to the cover layers on the CTR Nova Iguaçu and Dump of Seropédica. Six test trials of the Flux chamber, pressure measurement and concentration of gases in the soil-residue contact and emissions of gases through the drains, in addition to in situ soil analysis and laboratory analysis. The tests trials were performed from October, 2012 to November, 2012. The results indicated no gas flow through the cover layer, which has a thickness of 1.10 m, of the dump of Seropédica, where the gas flow was only encountered through the drains. In CTR Nova Iguaçu, the gas flow was almost inexistent, even having a cover layer of thickness of 0.8 m.

ANP; FINEP; MCT / Misturas bifásicas líquido-gás são frequentemente transportadas em tubulações através de terrenos com relevos irregulares. Estas irregularidades ocasionam perturbações nos parâmetros do escoamento bifásico, portanto tornando-se necessário prever o comportamento destes escoamentos. Neste cenário, o presente trabalho estuda, numérica e experimentalmente, os efeitos causados por uma leve mudança de direção no escoamento bifásico. O estudo foi realizado para escoamentos bifásicos ar-água em padrão de golfadas em uma tubulação horizontal de 26 mm e 5,8 m de comprimento seguida de um trecho inclinado ascendente de 3,4 m de comprimento e mesmo diâmetro com uma leve mudança de direção de 7° com relação à horizontal. Na abordagem numérica utilizou-se o método de seguimento dos pistões (slug tracking), para prever o comportamento do escoamento quando se produz uma leve mudança de direção. O trabalho experimental foi realizado utilizando um circuito experimental projetado e instalado no LACIT/UTFPR. Nele, foram instalados sensores resistivos e transdutores de pressão em quatro pontos da seção de teste, chamadas estações de medida, com a finalidade de monitorar a evolução da fração do vazio, velocidade de translação da bolha, a pressão e os comprimentos do pistão de líquido e da bolha. Os resultados numéricos e experimentais foram comparados entre si como função dos resultados médios e de distribuições de frequência nas estações de medição, tendo sido observada uma boa concordância. / Two-phase, liquid-gas flow mixtures are usually transported through pipes stretching over irregular terrains. Those irregularities disturb the flow characteristics, thus predicting the behaviour of such disturbed flows becomes necessary. The present work introduces an experimental and numerical study on the effects of a slight direction change on the behaviour of a gas-liquid two-phase slug flow. The aforementioned study was carried out in a 1” (26 mm), 5.8-m long transparent pipe section followed by a +7o inclined pipe (3.4-m long) transporting air-water two-phase mixtures at different flow rates. This experimental rig was designed and assembled in the LACIT/UTFPR labs. Resistive sensors and pressure transducers were installed at four testing positions in the pipe, designated as metering stations. Void fractions, bubble translational velocities, in situ pressures and the lengths of the liquid slug and the bubble region – as well as the fluctuations of those flow parameters – were measured at these stations. A classical slug tracking approach was applied as the numerical scheme. That approach attempts at simultaneously solving the one-dimensional mass and momentum conservation equations for each instant of time, resulting in coupled system of pressure-velocity equations. A mathematical model to predict the flow behaviour at the pipe position where the change in direction occurred was developed and implemented. The equations of such mathematical model were implemented as source terms in the slug tracking model. The numerical results were compared to the experimental data using averaged results and frequency distribution of the data collected at the metering stations, and a good agreement was observed.

LACIT / Escoamentos bifásicos gás-líquido estão presentes em inúmeras aplicações de engenharia, como por exemplo, na produção de petróleo, onde óleo e gás escoam nas linhas de produção. A monitoração online do escoamento bifásico é de grande importância para operação segura e eficiente dos processos de produção. Assim, nos últimos anos tem-se buscando o desenvolvimento de técnicas simples e de baixo custo para monitoração do escoamento da produção. Das diversas formas que um escoamento bifásico se apresenta, o padrão de escoamento em golfadas é o mais comum nas linhas de produção. Este trabalho apresenta um sistema óptico infravermelho que mede especificamente a velocidade das bolhas de gás em um escoamento em golfadas. Esse sistema emprega componentes optoeletrônicos operando a 950 nm juntamente com uma peça adutora utilizada para manter estáticos o emissor e receptor de luz. O circuito eletrônico responsável pelo funcionamento do sensor é composto por três canais de medição modulados em frequências diferentes. Dessa forma pelo tempo de trânsito que uma bolha leva no percurso entre os canais, pode-se calcular a velocidade da bolha. Essa técnica óptica traz a vantagem de ser um sistema de medição não invasivo e pode ser utilizado para outros fluidos, mas é necessário adaptar o comprimento de onda de trabalho de acordo com as características do fluido a ser detectado. O sistema desenvolvido foi testado em uma planta piloto sob diversas condições operacionais e comparado com sensores de referência (wire-mesh e câmera de alta velocidade). Resultados obtidos mostram o bom desempenho do sistema com relação aos sensores de referência. / Gas-liquid two-phase flows are present in many engineering applications such as in petroleum production, where oil and gas stream in the production lines. The online monitoring of two-phase flow is of great importance for safe and efficient operation of production processes. Thus, in recent years there has been an attempt to develop simple and low cost techniques for flow production monitoring. Among the various ways a two-phase flow may occur in a pipe, the flow pattern known as slug flow is the most common in production lines. This work presents an infrared optical system that specifically measures the translational speed of gas bubbles in slugs flow. This system employs optoelectronic components operating at 950 nm along with a mechanical assembly used to assure optical alignment of light emitters and receivers. The electronic circuitry responsible for operating the sensor consists of three measuring channels modulated at different frequencies, thus by measuring the time lag a gas bubble needs to travel from one channel to another, one can calculate speed of gas bubble. This optical technique has the advantage of being a noninvasive measurement system and can be used for other fluids, but it is necessary to adapt the working wavelength according to the characteristics of the fluid to be detected. The developed system was tested in a pilot plant under various operating conditions and compared with reference sensors (wire-mesh and high-speed camera). Results show the good performance of the system with respect to the reference sensors.