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51	Conception et réalisation d'un microsystème pour la mesure d'encrassement organique, minéral et biologique dans les procédés - : intégration des régimes thermiques périodiques. / Microsystem conception and realisation to monitor organic, mineral and biologic fouling in processes : integration of periodic thermal regime Crattelet, Jonathan 17 December 2010 (has links) Dans les industries de procédés, les opérations de pompage et de transformation sont fondamentales et omniprésentes. Durant ces opérations unitaires (incluant des transferts de chaleur, de matière et de quantités de mouvement), les produits évoluent (réactions chimiques et biochimiques, croissances microbiennes, traitements thermiques, etc.) induisant dans de nombreux cas des phénomènes d'encrassement avec des cinétiques et des intensités variables. Les recherches issues de l’INRA ont conduit à la mise au point d’un capteur d’encrassement basé sur une analyse thermique différentielle et locale. Ce dernier permet le contrôle en continu et en ligne du niveau d’encrassement d’un équipement et a été protégé par brevet. L’entreprise Neosens a acquis une licence d’exploitation exclusive sur ce brevet afin de développer et commercialiser le produit dont les limites sont maintenant connues.Dans ce travail, nous visons à atteindre deux objectifs majeurs en vue de répondre aux nouvelles problématiques posées. Le premier doit permettre la mise au jour d’un capteur d’encrassement en utilisant les technologies microsystèmes. Le second vise la validation d’un nouveau mode de fonctionnement et d’une méthode pour le contrôle de l’encrassement. Ce travail s'appuie naturellement sur les travaux antérieurs et les principales phases de recherche ont porté sur la conception, la réalisation et l'intégration d'éléments sensibles sur les bases technologiques des microsystèmes, l'intégration des régimes thermiques permanent et périodique associés au traitement en ligne du signal et à la validation expérimentale aux échelles laboratoire, pilote et industrielles des géométries et configurations nouvelles.Les travaux de recherche ont permis de fiabiliser et d’améliorer considérablement les performances métrologiques. Le microsystème réalisé apparaît comme complémentaire du capteur existant en termes de limites de détection et de quantification. / In industrial processes including agro and bioprocess, fouling is considered to be a complex and misunderstood phenomenon. Unit operations (including heat, mass and momentum transfers) are carried out in continuous, batch or fed-batch processes. During these operations, the products may evolve (chemical and biochemical reactions, microorganisms growth and activity, etc.) and fouling may occur with a wide range of kinetics from minutes up to years and dimensions from micrometers up to centimeters. Research issued from INRA led to develop a fouling sensor based on local differential thermal analysis and to patent this system. The device enables on-line and continuous monitoring of fouling propensity. Neosens company acquired an exclusive licence and develop and commercialize the sensor whose operating limits are known. In this work, our scientific and technological objectives are to break new locks through: (i) the realization of a fouling sensor based on microsystems technologies, (ii) the investigation and validation of an alternative thermal working mode and a method for fouling monitoring. Based on the previous work, our research deals with conception, realisation and integration of components based on microsystems technologies, integration of permanent and periodic thermal regimes with on-line data treatment and experimental validation at laboratory, pilot-plant and industrial scales for new geometries and configurations.This work led to metrology improvement and reliability. The resulting microsensor seems to be a complement of previous sensor regarding detection and quantification limits Régime d’écoulement Microsystème Mems Membrane Implantation ionique Drie Tcr Biofilm Transfert thermique Régime thermique permanent Régime thermique périodique Flow regime Sensor Microsystem Ionic implantation Fouling Biofouling Heat transfer Permanent thermal regime Periodic thermal regime Industrial processes
52	Etude théorique et expérimentale des micro-lits fluidisés : hydrodynamique et modélisation numérique / Design of micro-fluidized beds by experiments and numerical simulations : flow regims diagonis and hydrodynamic study Quan, Haiqin 06 December 2017 (has links) Le travail de thèse porte sur l’étude et la mise au point de nouvelles technologies et de procédés miniaturisés en lit fluidisé. Ce procédé représente une véritable rupture technologique devant les procédés à lits fluidisé traditionnels et offre de nombreux avantages : surface d’échange élevée, bon mélange gaz-solide dans le réacteur, utilisation de faible quantité de produit, coût faible... La présente étude regroupe trois études : conception des micro-lits fluidisés, diagnostic et analyse de l’hydrodynamique des couches fluidisées et modélisation numérique.Dans ce travail quatre MFBs (Micro Fluidized Bed) de 20-4 mm ont été étudiés et comparés à deux réacteurs relativement grands de 100-50 mm. Le rapport du diamètre du réacteur à la hauteur statique des particules (Hs/Dt) a été fixé entre 1-4. La vibration mécanique a été appliquée dans le réacteur de 4 mm. Une nouvelle méthode de diagnostic des régimes de fluidisation a été développée. Elle est basée sur les analyses des fluctuations de pression et le traitement du signal. La modélisation numérique suivant la méthode Eulérien-Eulérien (2D) a été développée. Les résultats obtenus permettent d’identifier six régimes d'écoulement: lit fixe, bouillonnant, bouillonnant/pistonnage, pistonnage, pistonnage/turbulent et bouillonnant/turbulent. On note une fluidisation partielle autour de Hs/Dt=1-2, tandis que le régime de pistonnage s’installe rapidement après le minimum de fluidisation à Hs/Dt=3-4. Dans le réacteur de 4 mm, la fluidisation des particules du groupe B de Geldart montre une meilleure qualité. Les résultats numériques (modélisation) montrent une très bonne concordance avec les données expérimentales / Micro-fluidized bed (MFB) exhibits great advantages such as a large specific contact surface, a fast dissipation of heat (ideal for exothermic reactions) and better mass and heat transfers, but suffers from difficulties in precise control and shows strong frictional wall effect. Present study was conducted experimentally and numerically to understand fundamental hydrodynamics in MFBs. Experimental work was carried out in four MFBs of 20-4 mm compared to two relatively large beds of 100-50 mm using three types of particles (B347: 347 μm, 2475 kg/m3; B105: 105 μm, 8102 kg/m3; A63: 63.8μm, 2437 kg/m3). The ratio of static bed height (Hs) to bed diameter (Dt) was set between 1-4. Mechanical vibration was applied to the 4 mm bed. A new method for flow regimes diagnosis was developed based on pressure fluctuation analyses, which mainly include calculating the standard deviation, autocorrelation function, probability density function, power spectral density function and time-frequency analysis. Numerical simulations were performed under Eulerian-Eulerian framework in 2D. Six flow regimes were identified: fixed bed, bubbling, bubbling/slugging, slugging, slugging/turbulent and bubbling/turbulent. Partial fluidization is encountered at Hs/Dt=1-2 while slugging prevails quickly after minimum fluidization at Hs/Dt=3-4. In the 4 mm bed, fluidization of B347 particles show better fluidization quality, while an increase in Umf is observed for B105 and A63 particles. Mechanical vibration reduces partial fluidization, thus resulting in larger ΔP and smaller Umf. A larger Umb and a delayed Uc were obtained as well. Results by simulations agree reasonably well with experimental data Lit micro-fluidisé L'effet de paroi Régime d'écoulement Simulation numérique Fluctuation de la pression Diamètre du lit Hauteur du lit statique Micro-fluidized bed Wall street Flow regime Numerical simulation Pressure fluctuation Bed diameter Static bed height
53	THE INFLUENCE OF SEASON, FLOW REGIME, AND WATERSHED LAND USE AND LAND COVER ON NUTRIENT DELIVERY TO TWO RAPIDLY URBANIZING WATERSHEDS IN CENTRAL INDIANA, USA Casey, Leda René 20 March 2007 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / This study explores relationships between temperate stream geochemistry and watershed land cover in two temperate streams, Fishback Creek and School Branch Creek, located in a rapidly urbanizing area on the northwest side of Indianapolis in Eagle Creek Watershed, Indiana. The temporal and spatial patterns of NO3-N, PO4, DOC, SiO2, Cl-, and Na+ were assessed to understand the influence of land cover on the magnitude and timing of water, chemical, and nutrient delivery to streams. Results of the study indicate that the influences of different land cover types on water delivery to streams and in-stream water quality vary seasonally and with respect to flow regime, that urbanization may result in decreased nitrate input, and that phosphate and dissolved organic carbon concentrations will likely remain constant as the watershed is developed. Results also indicate that riparian buffer downstream of intense agriculture lands dilutes high agricultural NO3-N concentrations, but not enough to return in-stream concentrations to natural levels. watershed land use land cover nutrient seasonal variation flow regime Geochemistry -- Indiana -- Indianapolis Watersheds -- Indiana -- Indianapolis Land use -- Indiana -- Indianapolis
54	Development of Boundary Singularity Method for Partial-Slip and Transition Molecular-Continuum Flow Regimes with Application to Filtration Zhao, Shunliu 01 September 2009 (has links) No description available. Mechanical Engineering Mechanics Boundary Singularity Method Stokeslet Creeping Flow Partial-Slip Transition Flow Regime Method of Fundamental Solutions Fibrous Filtration Micro-Flow Direct Simulation Monte Carlo Hybrid Continuum-Molecular Method Stokes Equations
55	Transport Phenomena in Complex Two and Three-Phase Flow Systems Akbar, Muhammad Khalid 22 November 2004 (has links) Two and three-phase flow processes involving gas, liquid and solid, are common in nature and industry, and include some of the most complex and poorly-understood transport problems. In this research hydrodynamics, heat and mass transfer processes in complex two and three-phase flows were investigated. The interfacial surface area concentration in a short vertical column subject to the through flow of fiber-liquid-gas slurry was experimentally measured using the gas absorption technique. The experimental data were statistically analyzed for parametric effects, and were empirically correlated. The absorption of a gaseous species by a slurry droplet with internal circulation and containing reactive micro-particles was simulated, and parametrically studied. The micro-particles were found to enhance the absorption rate. The absorption rate was sensitive to droplet recirculation, and shrinkage of particles with time resulted in declining absorption rates. The transport of soot particles, suspended in laminar hot gas flowing in a tube, was modeled and parametrically studied. Due to coupled thermal radiation and thermophoresis, a radially-nonuniform temperature profile develops, leading to sharp, non-uniform radial soot-concentration profiles. The assumption of monodisperse particles leads to over-prediction of thermophoresis. The transport and removal of particles suspended in bubbles rising in a stagnant liquid pool were modeled based on a Eulerian – Monte Carlo method. The bubble hydrodynamics were treated in Eulerian frame, using the Volume-of-Fluid (VOF) technique, while particle equations of motion were numerically solved in Lagrangian frame. The bubbles undergo shape change, and have complex internal circulation, all of which influence the particle removal. Model predictions were also compared with experimental data. Using a resemblance between two-phase flow in microchannels, and in large channels at microgravity, a simple Weber number-based two-phase flow regime map was developed for microchannels. Based on the available air-water experimental data, a criterion for the prediction of conditions that lead to flow regime transition out of the stratified-wavy flow pattern in horizontal annular channels was proposed. The thermocapillary effects on liquid-vapor interface shape during heterogeneous bubble ebullition in microchannels were analytically studied. Thermocapillary effects on bubble shape Desulfurization systems Slurry droplet Interfacial surface area concentration Log-normally-distributed particles Two-phase flow in microchannels Distortion of the bubble Stratified flow regime Fiber-Liquid-Gas three phase flow Transport of particles in rising bubbles Transport theory Fluid mechanics Mass transfer Multiphase flow
56	OBJECTIVE FLOW PATTERN IDENTIFICATION AND CLASSIFICATION IN INCLINED TWO-PHASE FLOWS USING MACHINE LEARNING METHODS David H Kang Jr (15352852) 27 April 2023 (has links) <p>Two-phase modeling and simulation capabilities are strongly dependent on the accuracy of flow regime identification methods. Flow regimes have traditionally been determined through visual observation, resulting in subjective classifications that are susceptible to inconsistencies and disagreements between researchers. Since the majority of two-phase flow studies have been concentrated around vertical and horizontal pipe orientations, flow patterns in inclined pipes are not well-understood. Moreover, they may not be adequately described by conventional flow regimes which were conceptualized for vertical and horizontal flows. Recent work has explored applying machine learning methods to vertical and horizontal flow regime identification to help remedy the subjectivity of classification. Such methods have not, however, been successfully applied to inclined flow orientations. In this study, two novel unsupervised machine learning methods are proposed: a modular configuration of multiple machine learning algorithms that is adaptable to different pipe orientations, and a second universal approach consisting of several layered algorithms which is capable of performing flow regime classification for data spanning multiple orientations. To support this endeavor, an experimental database is established using a dual-ring impedance meter. The signals obtained by the impedance meter are capable of conveying distinct features of the various flow patterns observed in vertical, horizontal, and inclined pipes. Inputs to the unsupervised learning algorithms consist of statistical measures computed from these signals. A novel conceptualization for flow pattern classification is developed, which maps three statistical parameters from the data to red, green, and blue primary color intensities. By combining the three components, a flow pattern map can be developed wherein similar colors are produced by flow conditions with like statistics, transforming the way flow regimes are represented on a flow regime map. The resulting dynamic RGB flow pattern map provides a physical representation of gradual changes in flow patterns as they transition from one regime to another. By replacing the static transition boundaries with physically informed, dynamic gradients between flow patterns, transitional flow patterns may be described with far greater accuracy. This study demonstrates the effectiveness of the proposed method in generating objective flow regime maps, providing a basis for further research on the characterization of two-phase flow patterns in inclined pipes. The three proposed methods are compared and evaluated against flow regime maps found in literature.</p> Two-Phase Flow Inclined Machine Learning Flow Regime Impedance Meter Flow Visualization Principal Components Analysis (PCA) RGB Color Model
57	Exprimental_Analysis_On_The_Effects_Of_Inclination_On_Two_Phase_Flows_DrewRyan_Dissertation.pdf Drew McLane Ryan (14227865) 07 December 2022 (has links) <p> </p> <p>The study of two-phase flow in different orientations can allow for greater understanding of the fundamentals of two-phase flow dynamics. While a large amount of work has been performed for vertical flows and recent work has been done for horizontal flows, limited research has been done studying inclined upward two-phase flows between those two orientations. Studying two-phase flows at various inclinations is important for developing physical models and simulations of two-phase flow systems and understanding the changes between what is observed for symmetric vertical flows and asymmetric horizontal flows. The present work seeks to systematically characterize the effects of inclination on adiabatic concurrent air-water two-phase flows in straight pipes. An experimental database is established for local and global two-phase flow parameters in a novel inclinable 25.4 mm inner diameter test facility using four-sensor conductivity probes, high speed video capabilities, a ring-type impedance meter, a pressure transducer, and a gamma densitometer. Rotatable measurement ports are employed to allow for local conductivity probe measurements across the flow profile to capture asymmetric parameter distributions during experiments without stopping the flow. Some of the major effects of inclination are investigated, including the effects on flow regime transition, bubble distribution, frictional pressure loss, and relative motion between the two phases. Flow visualization and machine-learning methods are employed to identify the transitions between flow regimes for inclined orientations, and these transitions are compared against existing theoretical flow regime transition criteria proposed in literature. The theoretical transitions in literature agree well with both methods for vertical flow, but additional work is necessary for angles between 0 degrees and 60 degrees. The effect of inclination on two-phase frictional pressure drop is explored, and a novel adaption of the Lockhart-Martinelli pressure drop correlation is proposed, which is able to predict the pressure drop for the conditions investigated with an absolute percent difference of 2.6%. To explore the relationships between orientation, void fraction, and relative motion, one-dimensional drift flux analyses are performed for the data at each angle investigated. It is observed that the relative velocity between phases decreases as the angle is reduced, with a relative velocity near zero at some intermediate angles and a negative relative velocity for near-horizontal orientations. Existing modeling capabilities that have been developed for vertical and horizontal flows are evaluated based on the local two-phase parameters collected at multiple orientations. The performance of the one-dimensional interfacial area transport equation for vertical and horizontal flows is tested against experimental data and a novel model for horizontal and inclined-upward bubbly flows is proposed. Finally, an evaluation of existing momentum transfer relations is performed for the two-fluid model using three-dimensional computational fluid dynamics tools for horizontal and inclined. The prediction of the void fraction distribution and gas velocity profiles are compared against experimental data, and improvements to the lift force model are identified based on changes in the relative velocity between phases. </p> Two-Phase Flow Inclination Local Conductivity Probe Void Fraction Drift Flux Model Interfacial Area Transport Flow Visualization Flow Regime Machine Learning Computational Fluid Dynamics
58	Testing and Refining a Unique Approach for Setting Environmental Flow and Water Level Targets for a Southern Ontario Subwatershed Beaton, Andrew 15 August 2012 (has links) In this study Bradford’s (2008) approach for setting ecological flow and water level targets is tested and refined through application within the Lake Simcoe Region Conservation Authority’s (LSRCA) subwatershed of Lover’s Creek. A method for defining subwatershed objectives and identifying habitat specialists through expert input is proposed and tested. The natural regime of each streamflow and wetland site is characterized along with the hydrological alteration at each site. Potential ecological responses to the hydrologic alterations are then hypothesized for the different types of changes calculated at each site. Methods for setting overall ecosystem health and specific ecological objective flow targets are proposed and tested. These targets are integrated into a flow regime for each site and a process for using this information for decision making is suggested. Flow magnitude quantification is attempted using hydraulic modelling and sediment transport equations, however the data used were found to be inadequate for this application. The accuracy of the targets developed using the method presented in this paper is mainly limited by the accuracy of the hydrological model and quantified flow magnitudes. Recommendations for improving these components of the assessment are made. The unique approach and recommendations presented in this paper provide explicit steps for developing flow targets for subwatersheds within the LSRCA. This research contributes toward the advancement of EFA within the LSRCA, which provides opportunity for enhanced protection and restoration of ecosystem health across the watershed. / Lake Simcoe Region Conservation Authority Ecological flows environmental flow instream flow in-stream flow indicators of hydrologic alteration ecological flow components Lovers Creek Lake Simcoe Watershed streamflow wetland hydroperiod MIKE-SHE HEC-RAS HEC-GeoRAS Du Boyes equation Ontario Stream Assessment Protocol OSAP IHA Southern Ontario Ontario LSRCA flow regime decision making Ontario hydrologic model hydraulic model brook trout amphibian swamp Ontario Wetland Evaluation System ecological function hydrological function expert interview Delphi Technique geomorphic framework river stream hydrology cold water fish Andrea Bradford aquatic aquatic habitat aquatic biology groundwater land use change urbanization pool riffle pool-riffle

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