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1
Franks, Peter J. "Estimation of cardiac output by a single breath method." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/32997.
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Many attempts have been made to quantify cardiac output using both invasive and non-invasive techniques. The results have generally been poorly reproducible and comparisons of techniques have yielded highly variable values. A single breath inert gas method was used in the study, since it offers several advantages over previous methods, chiefly its speed of measurement, and the controlled manner in which it is performed. The method observes the uptake of a semi-soluble inert gas (Freon-22) with respect to an insoluble marker, and calculates cardiac output (pulmonary flow) from the slope of the semi-soluble gas.
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Cai, Shiqian. "An artificial neural network method for three phase flow measurement." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/8227.
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Wei, Datong. "Quantitative and continuous measurement of cerebral blood flow by a thermal method." Case Western Reserve University School of Graduate Studies / OhioLINK, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=case1060354210.
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Ali, Maythem. "Development of an electromagnetic induction method for non-invasive blood flow measurement." Thesis, University of Huddersfield, 2016. http://eprints.hud.ac.uk/id/eprint/28706/.
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Blood flow is an important measurement in the diagnosis of cardiovascular diseases – the main cause of death globally. Cardiovascular diseases are often associated with atherosclerosis, which is a condition that causes the narrowing of arteries due to a buildup of lipids on the wall of the arterial vessels. Atherosclerosis occurring in the upper or lower limbs (referred to as peripheral arterial diseases) may lead to heart attack, stroke or severe health complications. Early detection of peripheral arterial diseases will enable primary prevention, and thus a reduction in morbidity, mortality and associated resources and financial costs. Limitations and drawbacks in the current methods for peripheral arterial blood flow measurement were primary factors in directing this research, which focuses on developing a reliable, easy-to-use and low-cost, non-invasive blood flow metering method that can replace or be an alternative option to current methods. This thesis describes the design and development of a novel electromagnetic induction method that can be used for peripheral arterial blood flow measurement non-invasively. In general terms, an electromagnetic induction flow metering technique is desirable because it is linear and insensitive to viscosity, temperature, conductivity and pressure loss. Additionally, and unlike previous non-invasive electromagnetic blood flow meters, the proposed method can be calibrated offline and is insensitive to velocity profile. The latter is important in obtaining measurements with high accuracy as blood flow in mammals is asymmetric. A mathematical model was developed for the proposed electromagnetic induction method based on the theory of “weight functions” by Shercliff and the “virtual current” theory by Bevir. This model demonstrated that, for multiple flow channels within a cross-sectional area bounded by a multi-electrode array and across which a uniform magnetic field is applied, flow induced potentials, due to the flow interaction with the magnetic field, can be predicted. From these flow induced potentials, the total volumetric flow rate can be found, irrespective of the number, size and location of the flow channels within the area bounded by the electrode array using a technique based on the Discrete Fourier Transform method. This proposed method allows the venous and arterial blood flow in a limb to be found. Next, a finite element model was developed in COMSOL Multiphysics software to validate the theoretical work. This was achieved by modelling multiple flow channels within a cylindrical region and obtaining flow induced potentials, which were compared with the theoretical values. From these induced potentials, the volumetric flow rate was found, using the DFT method, and confirmed. Finally, a practical model was designed and built which consisted of a physical pipework model (simulating a human limb), an electromagnet and signal conditioning and processing systems. Flow induced potential difference measurements were made using this model and compared with the predicted theoretical values. Overall, a good agreement was found between the theoretical results, computer simulations and practical results. Based on this work and additional work that is suggested in thisresearch, a medical prototype non-invasive electromagnetic blood flow meter device can be developed for clinical trials.
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Onilude, Ayodele. "A novel method for phase distribution measurement in water continuous two-phase flow." Thesis, University of Huddersfield, 2017. http://eprints.hud.ac.uk/id/eprint/34406/.
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Multiphase flows are occurring in several areas of the process industries. It is the concurrent flow of a mixture of fluid and solid components/phases. The multiphase flows are dependent on the flow regimes, the pipe orientation and the flow properties of the constituent phases such as the flow velocity and the volume fraction. Solids-liquid flows, such as slurries it occurs in horizontal and inclined pipes. Slurries have been used for transporting solid materials over long and short distances in various industries; these industries include the oil and gas industry, the mining industry and the food industry. Within these industries, the measurement of the multiphase flow parameters such as the local volume fraction distribution and the local axial velocity distribution of the solids dispersed in liquid in slurries are required parameters, for example for quantifying the local volume fraction for flow optimisation. The individual phases within the multiphase flow can be unpredictable and time dependent. Therefore, it is important to constantly monitor and measure the local flow parameters. The measurement of the local flow parameters in multiphase flows is very challenging. There are several solutions for measuring these flow parameters such as invasive sensing techniques, which have the tendency to alter the flow regime, while the non-invasive techniques allow for measurement without altering the flow profile. This thesis proposes a novel design and development of a non-invasive phase monitoring device PMD, which determines the local solids volume fraction of a discontinuous phase dispersed in an electrically conducting continuous phase of a multiphase flow. Extensive simulation was carried out to validate the design and optimisation of the electrode probe to be used for acquiring the boundary measurements. In this thesis, the associated electronic circuitry for the PMD were designed, signal processing and a relevant reconstruction algorithm were also developed for acquiring the boundary measurements and presenting the measurement information quantitatively and qualitatively respectively. A novel reference apparatus was designed as an accurate point of reference to investigate the accuracy of PMD. A series of experiments were carried out in order to measure the local solid volume fraction of the dispersed phase for various simulated non-uniform and uniform flow conditions. The results obtained indicate good quantitative agreement with reference measurements of the local solids volume fraction. The local volume fraction measurement technique described and presented in this thesis, is simpler, more accurate and less expensive than popular techniques such as the dual-plane Electrical Resistance Tomography (ERT).
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Alvarez, Merino José Carlos Daniel, and Alvarez Adrian Eduardo Palomo. "Instrument for measuring air speed by means of parabolic movement and measuring method." Universidad Peruana de Ciencias Aplicadas (UPC), 2018. http://hdl.handle.net/10757/624347.
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Patente de tipo Aplicación (US20180245954A1). 30 de Agosto de 2018.The invention relates to an instrument for measuring air speed by means of parabolic movement and to a measuring method, wherein the measuring instrument is formed by a cubic structure (1) that holds a screwable, flexible container (2) which releases—where air speed needs to be measured—a drop of liquid, the drop falling on one of the concentric circles located on an interchangeable plate (3) that is positioned on a flat base (4) of the device and perpendicular to the axial end of the outlet for the drop of liquid. Depending—on the height—the movement with which the drop falls, the air speed can be determined by means of the horizontal range of the parabolic movement followed by the drop of liquid, and evaluated using the distance be ween the point of impact of the drop on the surface with respect to the center. The direction of the air speed can also be determined from angle formed by the projection of the vertical plane above which projection the air moves in relation to the x-axis of the x-y plane located above the interchangeable plate (3).
7
張啓軍 and Qijun Zhang. "The Galerkin Element Method and power flow in acoustic-structural problems with damped sandwich plates." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1999. http://hub.hku.hk/bib/B31239742.
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Pasquini, Enrico, Heiko Baum, Bebber David van, and Denis Pendovski. "Numerical Simulation of Transient Diabatic Pipe Flow by using the Method of Characteristics." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199881.
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The following paper presents a one-dimensional numerical model for simulating transient thermohydraulic pipe flow based on the Method of Characteristics. In addition to mass and momentum conservation, the proposed scheme also guarantees compliance with the laws of thermodynamics by solving the energy equation. The model covers transient changes in fluid properties due to pressure changes, heat transfer and dissipation. The presented methodology also allows the computation of the transient temperature distribution in the pipe wall through an additional ordinary finite difference scheme. The numerical procedure is implemented in the commercial simulation software DSHplus. The capability of the code is examined by comparing the simulation results with theoretical solutions and experimental data.
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MacLean, Matthew. "A Numerical Study of Internal Flow Effects on Skin Friction Gages." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/27114.
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This work examines the detailed flow characteristics of direct measuring skin friction gages with computational methods. This type of device uses a small movable head mounted flush to a wall such that the head is assumed to be exposed to the same shear stress from the flow as the surrounding wall. The force caused by the action of the shear stress on the head deflects a flexure system monitored by instruments such as strain gages mounted at the base of a beam.
The goal of the study was to develop an understanding of the effects that the geometric design and installation parameters of the sensor have on the surrounding flow and the ability of the sensor to reflect the undisturbed shear stress value. Disruption of the external flow due to poor design and/or improper installation of the sensor can take the form of intrusion into the flow, recession into the wall, and/or tilted alignment of the sensor such that the head is not flat in the plane of the wall, as well as flow into or out of the small gap surrounding the sensing head. Further, the performance of a direct measuring skin friction sensor in the presence of a pressure gradient has always been a concern. These effects are studied here with a three-dimensional, Navier-Stokes code based on a finite element method technique.
Numerical solutions for cases in which one or more design parameters were varied are shown for a variety of flow situations. These situations include: (a) a laminar fully-developed channel flow at a low Reynolds number, (b) a turbulent flat plate boundary layer flow at a high Reynolds number, and (c) strong favorable and adverse pressure gradient turbulent boundary layer flows created by converging and diverging channels at high Reynolds number. Reported results for all cases include detailed flow visualization and stress field imagery, and total surface forces on the sensing head and gage flexure. Under ideal circumstances, these total forces should reflect as accurately as possible the average value of undisturbed shear stress times the exposed sensing head area (the friction force). Any deviation from this value was considered an â errorâ in the simulated measurement.
The laminar channel flow case with a strong favorable pressure gradient showed the importance of proper alignment of the sensor. Protrusion or recession of the sensing head proved to be the dominant effect on resulting forces seen by the gage, changing the output by up to 15% for head protrusion and 10% for head recession for misalignments up to +/-1% of the head diameter. The thickness of the lip on the edge of the head also proved to have a significant effect on the output, with a smaller lip thickness generally showing better performance than a large one. Zero lip thickness indicated accuracy to within 1% of the desired wall shear result, since the pressure differences had little influence on the sensing head. Finally, the assumption of a linear pressure variation from the surface to the cavity along the lip as has been suggested in the past was investigated. The results indicate that the linear assumption works well only for large ratios of lip thickness to gap size, a fact which is correlated with previous experimental results.
For the turbulent external flat plate case, misalignment remained the dominant effect on the sensor response. Results indicated that, in general, protrusion is more costly than the same level of recession, and a protrusion of +1% of the head diameter was shown to cause in excess of 100% error in indicated wall shear output. Both protrusion and recession produced large variations in both force and moment on the sensing flexure, but the outcome was that for protrusion the errors caused by these two effects tended to sum together, while for recession they tended to partially cancel out.
The gap size played an increased role in the high Reynolds number boundary layer cases. Gap sizes of 1.67% up to 6.67% of the head diameter were studied and were shown to produce output errors between 4% and 22% (with larger errors corresponding to larger gap sizes), thus showing the importance of minimizing the gap for high Reynolds number flows. The lip was shown to have no significant effect for a flow without a pressure gradient.
Finally, the favorable and adverse pressure gradient flows showed reasonable performance of the skin friction gage. Errors in output were shown to be -6% for the favorable pressure gradient case and 17% for the adverse pressure gradient case. Only the baseline gage design was studied for these situations, but the results from the two cases indicate that further reducing the lip thickness may not improve the performance of the gage. The error in output was caused almost entirely by applied moment for the adverse pressure gradient, while the applied force and applied moment had a cancellation effect in the favorable pressure gradient case.
As a general result, the use of computational fluid dynamics has been shown to be an effective tool in the design and analysis of skin friction gages. Using a computational approach has the advantage of being able to resolve the small, confined gap regions of the gage, providing information that has been shown to be unavailable from previous experimental studies. This work has contributed to a much better understanding of the detailed flow over, in, and around skin friction gages. This will lead to improved gage design and reduced uncertainty in these important measurements.Ph. D.
10
Gaic, Pierre. "Developpement et mise au point d'un systeme de mesure couplee des tailles et vitesses des particules au sein d'un ecoulement diphasique disperse." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13300.
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Mise au point et developpement d'une methode optique de mesure couplee des tailles et vitesses des particules au sein d'un ecoulement diphasique disperse. Confection d'un prototype complet utilise pour etudier le nuage de gouttelettes produit par un injecteur pneumatique
11
Carvalho, Julene de Souza. "Analysis of the clinical utility of a modified plethysmographic method for indirect measurement of instantaneous pulonary capillary blood flow." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362366.
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Fain, Danny 1966. "Use of the self-potential method for measurement of subsurface water flow at a pump-and-treat remediation site." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9319.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999.Includes bibliographical references (leaf 34).
The self-potential method (SP) of geophysical surveying has been widely used in environmental and engineering applications, primarily for rough but inexpensive assessment of subsurface flow of fluids, heat, or ions. In this project, the SP method was employed to study the activity at an environmental cleanup site at the Massachusetts Military Reservation. At the leading (down-gradient) edge of the CS-4 groundwater contamination plume, a fence of pump-and-treat extraction wells has been operating in an effort to contain the plume migration. To help gauge the effectiveness of the pump-and-treat technique, it is useful to delineate the resultant water flow and to compare it to the extent and diffusion gradient of the contaminant plume. In the survey conducted for this project, SP measurements were taken along the fence of extraction wells, while they were in operation, and during a period in which the well pumps were shut off. Spatial and temporal variations in the SP measurements are analyzed. Some possible explanations are proposed to account for the observed features and changes over time. While the results are not entirely conclusive, they suggest that water flow provides only a modest contribution to the total observed SP anomaly.
by Danny Fain.
S.B.
13
Terayama, Kei. "Vision-based Measurement Methods for Schools of Fish and Analysis of their Behaviors." Kyoto University, 2016. http://hdl.handle.net/2433/215633.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第19807号
人博第778号
新制||人||187(附属図書館)
27||人博||778(吉田南総合図書館)
32843
京都大学大学院人間・環境学研究科共生人間学専攻
(主査)教授 立木 秀樹, 准教授 櫻川 貴司, 教授 日置 尋久, 教授 阪上 雅昭
学位規則第4条第1項該当
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Valdová, Klára. "Posouzení metody stanovení průtoku jímáním kapaliny do odměrné nebo vážicí nádoby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2016. http://www.nusl.cz/ntk/nusl-240089.
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This diploma thesis is concerned with assessment of two methods of gauging the flow rate used in the sphere of official measurements on profiles with an unrestricted water level. This is the method of collecting liquid into a volumetric vessel and the method of collecting liquid into a weighing vessel (pouch). The main purpose of this work was to specify uncertainties determined using method A and B for these two methods of gauging flow rate within the terms of addressing the Metrology Development Plan of the Czech Office for Standards, Metrology and Testing, because these uncertainties were previously determined using older methodology and using less accurate flow rate benchmarks. The entire work is based on extensive experimental measurement of the flow rate, using the assessed methods, executed at the Laboratory of Water Management Research in Brno. The method of collecting liquids into a volumetric vessel was assessed using four various vessel volumes - 9 l, 15 l, 30 l and 50 l. Relative uncertainties determined using method A and B in relation to flow rate are determined for each vessel in the experimental section of this work. Within the scope of this thesis, these uncertainties were also determined for the method of collection of liquid into weighing vessel (pouch), which was assessed for flow rates of from 0,5 l/s to 10,0 l/s.
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Dinh, Quang Hung. "Development of a Rapid and Easy Measurement Protocol for Perfluorinated Carboxylic Acids (PFCAs) by a Continuous Flow Analysis." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/204596.
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Hahm, Jungyoon. "Numerical simulation of electrokinetically driven micro flows." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2594.
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Spectral element based numerical solvers are developed to simulate electrokinetically
driven flows for micro-fluidic applications. Based on these numerical solvers,
basic phenomena and devices for electrokinetic applications in micro and nano flows
are systematically studied. As a first application, flow and species transport control
in a grooved micro-channel using local electrokinetic forces are studied. Locally
applied electric fields, zeta potential patterned grooved surfaces, and geometry are
manipulated to control mixed electroosmotic/pressure driven flow in the grooved
micro-channel. The controlled flow pattern enables entrapment and release of prescribed
amounts of scalar species in the grooves. As another application, hydrodynamic/
electrokinetic focusing in a micro-channel is studied. External electric field,
flow rate of pressure driven flow, and geometry in the micro-channel are manipulated
to obtain the focusing point, which led to determination of the electrophoretic mobility
and (relative) concentration of dilute mixtures. This technique can be used to
identify and detect species in dilute mixtures.
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Cathelyn, Jim, and L. Lee Glenn. "Effect of Ambient Temperature and Cardiac Stability on Two Methods of Cardiac Output Measurement." Digital Commons @ East Tennessee State University, 1999. https://dc.etsu.edu/etsu-works/7534.
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The dependence of cardiac output measurement precision on ambient temperature and cardiac output stability was assessed by concurrent continuous and bolus thermodilution methods in postoperative cardiac surgery patients. The degree of agreement between the two methods was depended on room temperature (0.1 L/min for each degree below 25 degrees C). The agreement was also closer in trials where cardiac output was stable (< 10% variation). The continuous thermodilution method shows sufficient agreement with the bolus method for use in critical care; however, improved precision of cardiac output thermodilution measurements can be achieved by use of correction factors for cardiac instability and for ambient temperature.
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Zhong, Hua, Ouni Asma El, Dan Lin, Bingguo Wang, and Mark L. Brusseau. "The two-phase flow IPTT method for measurement of nonwetting-wetting liquid interfacial areas at higher nonwetting saturations in natural porous media." AMER GEOPHYSICAL UNION, 2016. http://hdl.handle.net/10150/622507.
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Interfacial areas between nonwetting-wetting (NW-W) liquids in natural porous media were measured using a modified version of the interfacial partitioning tracer test (IPTT) method that employed simultaneous two-phase flow conditions, which allowed measurement at NW saturations higher than trapped residual saturation. Measurements were conducted over a range of saturations for a well-sorted quartz sand under three wetting scenarios of primary drainage (PD), secondary imbibition (SI), and secondary drainage (SD). Limited sets of experiments were also conducted for a model glass-bead medium and for a soil. The measured interfacial areas were compared to interfacial areas measured using the standard IPTT method for liquid-liquid systems, which employs residual NW saturations. In addition, the theoretical maximum interfacial areas estimated from the measured data are compared to specific solid surface areas measured with the N-2/BET method and estimated based on geometrical calculations for smooth spheres. Interfacial areas increase linearly with decreasing W-phase (water) saturation over the range of saturations employed. The maximum interfacial areas determined for the glass beads, which have no surface roughness, are 32 +/- 4 and 36 +/- 5 cm(-1) for PD and SI cycles, respectively. The values are similar to the geometric specific solid surface area (31 +/- 2 cm(-1)) and the N-2/BET solid surface area (28 +/- 2 cm(-1)). The maximum interfacial areas are 274 +/- 38, 235 +/- 27, and 581 +/- 160 cm(-1) for the sand for PD, SI, and SD cycles, respectively, and similar to 7625 cm(-1) for the soil for PD and SI. The maximum interfacial areas for the sand and soil are significantly larger than the estimated smooth-sphere specific solid surface areas (107 +/- 8 cm(-1) and 152 +/- 8 cm(-1), respectively), but much smaller than the N-2/BET solid surface area (1387 +/- 92 cm(-1) and 55224 cm(-1), respectively). The NW-W interfacial areas measured with the two-phase flow method compare well to values measured using the standard IPTT method.
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Woods, Juliette Aimi. "Numerical accuracy of variable-density groundwater flow and solute transport simulations." Title page, contents and abstract only, 2004. http://web4.library.adelaide.edu.au/theses/09PH/09phw8941.pdf.
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Štarhová, Marie. "Posouzení metody využívající přenosnou měřicí sestavu s průtokoměrem." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372080.
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This diploma thesis deals with the assessment of flow measurement method using portable measuring set with the flowmeter used in the field of official measurement in the free surface profiles. This method is a controlled simulation of the required flow through a portable measurement set. This approach is innovative in relation to other methods of official measurement in which direct flow measurement is carried out. The thesis is based on extensive literary research related to elementary element of this assembly – flowmeter. On the basis of individual characteristics, the technical and metrological requirements for both the flowmeter and the other elements of the measuring set are processed. In the context of these findings and the requirements of the official measurement, input sources of measurement uncertainties are further defined and subsequently calculated by this assembly. The findings from this thesis are fully applicable to the practice of institution authorized for the official measurement of the subject method.
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Zeiner, Pavel. "Využití integrační metody pro měření průtoku v prostoru konfuzoru měrných žlabů typu Parshall." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227261.
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This diploma thesis deals with the measurement of flow rate in flumes type PARS P2, P3 and P4. First, there is a search for a convenient profile in confusor for research and consequently to construct graphical dependences from which to read the value of the correction coefficient for many water depths in flumes. Then, there are constructed graphical dependences from which to read the value of measurement uncertainty for many flow rates in flumes.
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CHO, DOO-YEARN. "Mesure du champ des vitesses de melanges solide-liquide par anemometrie laser a effet doppler." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13150.
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Un circuit logique incorpore dans la chaine de mesure permet de distinguer les signaux provenant des particules et du traceur visualisant le liquide porteur. L'association de l'anemometrie laser a effet doppler et d'un oscilloscope numerique rend possible l'echantillonnage du signal doppler. Un logiciel de traitement du signal permet de determiner les vitesses moyennes locales des particules solides spheriques en suspension et du liquide porteur. On peut obtenir ainsi simultanement les deux vitesses et la vitesse de glissement particule-liquide
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Gheraissa, Ferhat. "Mesure de la granulometrie dans les ecoulements diphasiques disperses et visualisation : application au traitement d'image." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13219.
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On utilise et on met au point differentes methodes: photographie a etincelle, cinematographie ultrarapide, granulometrie par diffusion de lumiere laser ou l'on mesure la fonction de repartition en se fixant des seuils d'intensite de lumiere diffusee, granulometrie par traitement d'image
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Benrabah, Omar. "Mesure des vitesses en milieu diphasique par velocimetrie laser : interaction entre le mouvement des particules solides et la turbulence." Université Louis Pasteur (Strasbourg) (1971-2008), 1988. http://www.theses.fr/1988STR13108.
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Un circuit logique incorpore a la chaine de mesure permet de distinguer entre les signaux provenant de la phase continue et ceux des grosses particules. On montre l'existence d'une vitesse de glissement solide-liquide qui depend de la concentration du diametre moyen des particules et de la vitesse d'ecoulement. La presence des particules solides reduit la turbulence du milieu porteur
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Putze, Torsten. "Geometrische und stochastische Modelle zur Optimierung der Leistungsfähigkeit des Strömungsmessverfahrens 3D-PTV." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1231402875520-12137.
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Die 3D Particle Tracking Velocimetry (3D PTV) ist eine Methode zur bildbasierten Bestimmung von Geschwindigkeitsfeldern in Gas- oder Flüssigkeitsströmungen. Dazu wird die Strömung mit Partikeln markiert und durch ein Mehrkamerasystem beobachtet. Das Ergebnis der Datenauswertung sind 3D Trajektorien einer großen Anzahl von Partikeln, die zur statistischen Analyse der Strömung genutzt werden können. In der vorliegenden Arbeit werden verschiedene neu entwickelte Modelle gezeigt, die das Einsatzspektrum vergrößern und die Leistungsfähigkeit der 3D PTV erhöhen. Wesentliche Neuerungen sind der Einsatz eines Spiegelsystems zur Generierung eines virtuellen Kamerasystems, die Modellierung von komplex parametrisierten Trennflächen der Mehrmedienphotogrammetrie, eine wahrscheinlichkeitsbasierte Trackingmethode sowie eine neuartige Methode zur tomographischen Rekonstruktion von Rastervolumendaten. Die neuen Modelle sind an drei realen Experimentieranlagen und mit synthetischen Daten getestet worden. Durch den Einsatz eines Strahlteilers vor dem Objektiv einer einzelnen Kamera und vier Umlenkspiegeln, positioniert im weiteren Strahlengang, werden vier virtuelle Kameras generiert. Diese Methode zeichnet sich vor allem durch die Wirtschaftlichkeit als auch durch die nicht notwendige Synchronisation aus. Vor allem für die Anwendung im Hochgeschwindigkeitsbereich sind diese beiden Faktoren entscheidend. Bei der Beobachtung von Phänomenen in Wasser kommt es an den Trennflächen verschiedener Medien zur optischen Brechung. Diese muss für die weitere Auswertung zwingend modelliert werden. Für komplexe Trennflächen sind einfache Ansätze über zusätzliche Korrekturterme nicht praktikabel. Der entwickelte Ansatz basiert auf der mehrfachen Brechung jedes einzelnen Bildstrahls. Dazu müssen die Trennflächenparameter und die Kameraorientierungen im selben Koordinatensystem bekannt sein. Zumeist wird die Mehrbildzuordnung von Partikeln durch die Verwendung von Kernlinien realisiert. Auf Grund von instabilen Kameraorientierungen oder bei einer sehr hohen Partikeldichte sind diese geometrischen Eigenschaften nicht mehr ausreichend, um die Mehrbildzuordnung zu lösen. Unter der Ausnutzung weiterer geometrischer, radiometrischer und physikalischer Eigenschaften kann die Bestimmung der 3D Trajektorien dennoch durchgeführt werden. Dabei werden durch die Analyse verschiedener Merkmale diejenigen ausgewählt, welche sich für die spatio-temporale Zuordnung eignen. Die 3D PTV beruht auf der Diskretisierung der Partikelabbildungen im Bildraum und der anschließenden Objektkoordinatenbestimmung. Eine rasterbasierte Betrachtungsweise stellt die tomographische Rekonstruktion des Volumens dar. Hierbei wird die Intensitätsverteilung wird im Volumen rekonstruiert. Die Bewegungsinformationen werden im Anschluss aus den Veränderungen aufeinander folgender 3D-Bilder bestimmt. Durch dieses Verfahren können Strömungen mit einer höheren Partikeldichte im Volumen analysiert werden. Das entwickelte Verfahren basiert auf der schichtweisen Entzerrung und Zusammensetzung der Kamerabilder. Die entwickelten Modelle und Ansätze sind an verschiedenen Versuchsanlagen erprobt worden. Diese unterschieden sich stark in der Größe (0,5 dm³ – 20 dm³ – 130 m³) und den vorherrschenden Strömungsgeschwindigkeiten (0,3 m/s – 7 m/s – 0,5 m/s)3D Particle Tracking Velocimetry (3D PTV) is an image based method for flow field determination. It is based on seeding a flow with tracer particles and recording the flow with a multi camera system. The results are 3D trajectories of a large number of particles for a statistical analysis of the flow. The thesis shows different novel models to increase the spectrum of applications and to optimize efficiency of 3D PTV. Central aspects are the use of the mirror system to generate a virtual multi camera system, the modelling of complex interfaces of multimedia photogrammetry, a probability based tracking method and a novel method for tomographic reconstruction of volume raster data. The improved models are tested in three real testing facilities and with synthetic data. Using a beam splitter in front of the camera lens and deflecting mirrors arranged in the optical path, a four headed virtual camera system can be generated. This method is characterised by its economic efficiency and by the fact that a synchronisation is not necessary. These facts are important especially when using high speed cameras. When observing phenomena in water, there will be refraction at the different interfaces. This has to be taken into account and modelled for each application. Approaches which use correction terms are not suitable to handle complex optical interfaces. The developed approach is based on a multiple refraction ray tracing with known interface parameters and camera orientations. Mostly the multi image matching of particles is performed using epipolar geometry. Caused by the not stable camera orientation or a very high particle density this geometric properties are not sufficient to solve the ambiguities. Using further geometrical radiometrical and physical properties of particles, the determination of the 3D trajectories can be performed. After the analysis of different properties those of them are chosen which are suitable for spatio-temporal matching. 3D PTV bases on the discretisation of particle images in image space and the following object coordinate determination. A raster based approach is the tomographic reconstruction of the volume. Here the light intensity distribution in the volume will be reconstructed. Afterwards the flow information is determined from the differences in successive 3D images. Using tomographic reconstruction techniques a higher particle density can be analysed. The developed approach bases on a slice by slice rectification of the camera images and on a following assembly of the volume. The developed models and approaches are tested at different testing facilities. These differ in size (0.5 dm³ – 20 dm³ – 130 m³) and flow velocities (0.3 m/s – 7 m/s – 0.5 m/s)
26
Ambari, Abdelhak. "Application des méthodes électrochimiques à l'étude de l'interaction entre l'hydrodynamique et la dynamique des polymères en écoulement élongationnel : interaction entre particules solides en régime de Stokes." Paris 6, 1986. http://www.theses.fr/1986PA066006.
Full textAbstract:
Dynamique des polymères linéaires et flexibles en écoulement élongationnel. Mise en évidence du changement brutal de la forme pelote à la forme étirée. Deux méthodes de mesure différentes : l'une basée sur la mesure directe de la dissipation viscoélastique, l'autre basée sur les effets de cette transition sur le transfert massique et sur l'hydrodynamique.
27
Hazzab, Abdelkrim. "Etude de la distribution spatiale de la concentration des particules solides en suspension dans une conduite." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13087.
Full textAbstract:
Mise au point d'un dispositif de mesure basee sur l'attenuation d'un faisceau laser par des particules de billes de verre. La methode est developpee pour les mesures a travers une conduite de verre. On developpe, par une approche algebrique, un algorithme pour reproduire la repartition spatiale de la concentration dans la section de mesure. Dans quelques cas, on determine l'evolution de la repartition spatiale en fonction de la concentration et de la vitesse moyenne d'ecoulement
28
Červinková, Kateřina. "Citlivostní analýza metody tlak-čas na nepřesnosti měření." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400848.
Full textAbstract:
The pressure-time method is one of two methods of measuring the flow rate on large hydraulic structures applicable to IEC 60041, which is based on the temporal integration of the measured pressure difference and the formation of a water hammer in a closed pipe. The aim of this master thesis is to perform a literature review of this method and to evaluate the flow rate of the measured data. Furthermore, the thesis deals with determination of the sensitivity of the evaluated flow rate to the weights of individual pressure sensors and to numerical modifying of the measured pressures. The first part is made using MS Excel. The flow rate is always evaluates with only one pressure sensor and it is compared with the original flow rate. There is research, how absence of the sensor has an impact on the evaluated flow rate. In the second part of the determination of the sensitivity of the evaluated flow rate, various encroachment (signal smoothing, noise, time delay, frequency band removal) are performed of measured pressure signal in Matlab. Various surrounding influences or sensors failures are simulated.
29
Bruna, Pascal. "Mise au point d'une méthode optique originale de détermination des probabilités de présence particulaire dans un aérosol dispersé par un écoulement turbulent." Rouen, 1988. http://www.theses.fr/1988ROUES034.
Full textAbstract:
La méthode utilise des techniques de traitement d'images enregistrées par une caméra photosensible linéaire. Un faisceau lumineux traverse une veine rectangulaire en amont de laquelle sont injectées des particules d'eau monodimensionnelles. Lors de leur passage dans le volume de mesure des photodiodes, elles émettent des signaux qui sont collectés, traités puis validés. On construit des histogrammes de probabilité de présence particulaire suivant l'axe des photodiodes
30
Putze, Torsten. "Geometrische und stochastische Modelle zur Optimierung der Leistungsfähigkeit des Strömungsmessverfahrens 3D-PTV." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23711.
Full textAbstract:
Die 3D Particle Tracking Velocimetry (3D PTV) ist eine Methode zur bildbasierten Bestimmung von Geschwindigkeitsfeldern in Gas- oder Flüssigkeitsströmungen. Dazu wird die Strömung mit Partikeln markiert und durch ein Mehrkamerasystem beobachtet. Das Ergebnis der Datenauswertung sind 3D Trajektorien einer großen Anzahl von Partikeln, die zur statistischen Analyse der Strömung genutzt werden können. In der vorliegenden Arbeit werden verschiedene neu entwickelte Modelle gezeigt, die das Einsatzspektrum vergrößern und die Leistungsfähigkeit der 3D PTV erhöhen. Wesentliche Neuerungen sind der Einsatz eines Spiegelsystems zur Generierung eines virtuellen Kamerasystems, die Modellierung von komplex parametrisierten Trennflächen der Mehrmedienphotogrammetrie, eine wahrscheinlichkeitsbasierte Trackingmethode sowie eine neuartige Methode zur tomographischen Rekonstruktion von Rastervolumendaten. Die neuen Modelle sind an drei realen Experimentieranlagen und mit synthetischen Daten getestet worden. Durch den Einsatz eines Strahlteilers vor dem Objektiv einer einzelnen Kamera und vier Umlenkspiegeln, positioniert im weiteren Strahlengang, werden vier virtuelle Kameras generiert. Diese Methode zeichnet sich vor allem durch die Wirtschaftlichkeit als auch durch die nicht notwendige Synchronisation aus. Vor allem für die Anwendung im Hochgeschwindigkeitsbereich sind diese beiden Faktoren entscheidend. Bei der Beobachtung von Phänomenen in Wasser kommt es an den Trennflächen verschiedener Medien zur optischen Brechung. Diese muss für die weitere Auswertung zwingend modelliert werden. Für komplexe Trennflächen sind einfache Ansätze über zusätzliche Korrekturterme nicht praktikabel. Der entwickelte Ansatz basiert auf der mehrfachen Brechung jedes einzelnen Bildstrahls. Dazu müssen die Trennflächenparameter und die Kameraorientierungen im selben Koordinatensystem bekannt sein. Zumeist wird die Mehrbildzuordnung von Partikeln durch die Verwendung von Kernlinien realisiert. Auf Grund von instabilen Kameraorientierungen oder bei einer sehr hohen Partikeldichte sind diese geometrischen Eigenschaften nicht mehr ausreichend, um die Mehrbildzuordnung zu lösen. Unter der Ausnutzung weiterer geometrischer, radiometrischer und physikalischer Eigenschaften kann die Bestimmung der 3D Trajektorien dennoch durchgeführt werden. Dabei werden durch die Analyse verschiedener Merkmale diejenigen ausgewählt, welche sich für die spatio-temporale Zuordnung eignen. Die 3D PTV beruht auf der Diskretisierung der Partikelabbildungen im Bildraum und der anschließenden Objektkoordinatenbestimmung. Eine rasterbasierte Betrachtungsweise stellt die tomographische Rekonstruktion des Volumens dar. Hierbei wird die Intensitätsverteilung wird im Volumen rekonstruiert. Die Bewegungsinformationen werden im Anschluss aus den Veränderungen aufeinander folgender 3D-Bilder bestimmt. Durch dieses Verfahren können Strömungen mit einer höheren Partikeldichte im Volumen analysiert werden. Das entwickelte Verfahren basiert auf der schichtweisen Entzerrung und Zusammensetzung der Kamerabilder. Die entwickelten Modelle und Ansätze sind an verschiedenen Versuchsanlagen erprobt worden. Diese unterschieden sich stark in der Größe (0,5 dm³ – 20 dm³ – 130 m³) und den vorherrschenden Strömungsgeschwindigkeiten (0,3 m/s – 7 m/s – 0,5 m/s).3D Particle Tracking Velocimetry (3D PTV) is an image based method for flow field determination. It is based on seeding a flow with tracer particles and recording the flow with a multi camera system. The results are 3D trajectories of a large number of particles for a statistical analysis of the flow. The thesis shows different novel models to increase the spectrum of applications and to optimize efficiency of 3D PTV. Central aspects are the use of the mirror system to generate a virtual multi camera system, the modelling of complex interfaces of multimedia photogrammetry, a probability based tracking method and a novel method for tomographic reconstruction of volume raster data. The improved models are tested in three real testing facilities and with synthetic data. Using a beam splitter in front of the camera lens and deflecting mirrors arranged in the optical path, a four headed virtual camera system can be generated. This method is characterised by its economic efficiency and by the fact that a synchronisation is not necessary. These facts are important especially when using high speed cameras. When observing phenomena in water, there will be refraction at the different interfaces. This has to be taken into account and modelled for each application. Approaches which use correction terms are not suitable to handle complex optical interfaces. The developed approach is based on a multiple refraction ray tracing with known interface parameters and camera orientations. Mostly the multi image matching of particles is performed using epipolar geometry. Caused by the not stable camera orientation or a very high particle density this geometric properties are not sufficient to solve the ambiguities. Using further geometrical radiometrical and physical properties of particles, the determination of the 3D trajectories can be performed. After the analysis of different properties those of them are chosen which are suitable for spatio-temporal matching. 3D PTV bases on the discretisation of particle images in image space and the following object coordinate determination. A raster based approach is the tomographic reconstruction of the volume. Here the light intensity distribution in the volume will be reconstructed. Afterwards the flow information is determined from the differences in successive 3D images. Using tomographic reconstruction techniques a higher particle density can be analysed. The developed approach bases on a slice by slice rectification of the camera images and on a following assembly of the volume. The developed models and approaches are tested at different testing facilities. These differ in size (0.5 dm³ – 20 dm³ – 130 m³) and flow velocities (0.3 m/s – 7 m/s – 0.5 m/s).
31
Bonilla, Riaño Adriana 1980. "Film thickness measurement with high spatial and temporal resolution planar capacitive sensing in oil-water pipe flow = Medida da espessura de filme usando sensor capacitivo de alta resolução espacial e temporal para escoamentos óleo-água em tubos." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265764.
Full textAbstract:
Orientadores: Antonio Carlos Bannwart, Oscar Mauricio Hernandez RodriguezTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências
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Resumo: Neste trabalho, é apresentado o desenvolvimento de uma nova técnica para a medição da espessura do filme de água com alta resolução espacial e temporal em escoamento óleo-água. É proposto o uso de um sistema de medição de capacitância elétrica para medir filmes finos de água na proximidade da parede do tubo. O sistema conta com um sensor planar e foi necessário determinar a melhor geometria via simulações baseadas no Método de Elementos Finitos (FEM) para o caso de escoamento óleo-água. As características comparadas foram a profundidade de penetração do campo elétrico no filme de água, a sensibilidade, a resolução espacial mínima e a resposta quase-linear. Padrões de escoamento óleo-água disperso e anular instável foram estudados numa tubulação vertical de 12 m de comprimento, feita de vidro, com 50,8 milímetros de diâmetro interno. Os fluidos usados foram óleo mineral (com densidade 828 kg/m3 e viscosidade 220 mPas) e água da torneira. O trabalho experimental foi realizado nas instalações de escoamento multifásico do Laboratório de Engenharia Térmica e Fluidos (NETeF) da EESC-USP. Foi medida a espessura média do filme de água usando o sistema capacitivo e uma câmera de vídeo de alta velocidade. Para obter a espessura do filme de água a partir das imagens, foi proposto um algoritmo de pré-processamento e um algoritmo de segmentação que combina vários métodos disponíveis na literatura. Os resultados experimentais do sensor capacitivo mostraram que o sistema pode medir espessuras entre 400 µm e 2200 µm. O escoamento anular instável é caracterizado por grandes flutuações na no sentido do escoamento e na direção do perímetro, e estruturas interfaciais grandes (gotas). Por sua vez, o escoamento disperso tem flutuações menores no sentido do escoamento e na direção do perímetro, e estruturas interfaciais menores (gotículas). Uma estrutura interfacial média no espaço e no tempo é proposta para modelar a interface entre a região próxima à parede do tubo e a região do núcleo, e sua análise foi feita no domínio do tempo e da frequência. Foram estudadas a amplitude, velocidade e o comprimento da estrutura interfacial em cada par transmissor-receptor do sensor. Foi possível estabelecer correlações para a velocidade das estruturas em escoamento de óleo em água
Abstract: The development of a new technique for high spatial and temporal resolution film thickness measurement in oil-water flow is presented. A capacitance measurement system is proposed to measure thin water films near to the wall pipe. A planar sensor was chosen for sensing and some geometries were compared using finite elements method (FEM). The penetration depth, the sensitivity, the minimum spatial resolution (high spatial resolution) and the quasi-linear curve were the analyzed characteristics. Dispersed and unstable-annular oil-water flows patterns were studied in a 12-m long vertical glass pipe, with 50.8 mm of internal diameter, using mineral oil (828 kg/m3 of density and 220 mPa s of viscosity) and tap water. The experimental work was carried out in the multiphase-flow facilities of The Thermal-Fluids Engineering Laboratory (NETeF) of EESC-USP. Experiments with a high-speed video camera and the proposed capacitance system were performed to obtain images of the oil-water flow near the pipe wall. A pre-processing enhancement algorithm and a combined segmentation algorithm are proposed and allowed the measurement of characteristic space and time averaged water film thickness. Experimental results of the capacitive technique showed that the system could measure thickness between 400 µm and 2200 µm. It was possible to recognize and characterize typical behaviors of the two different flow patterns studied. Unstable-annular flow can be described by huge fluctuations on the flow direction and perimeter direction, and big interfacial structures (drops). On the other hand, dispersed flow has tiny fluctuations on the flow direction and perimeter direction, and smaller interfacial structures (droplets). An interfacial structure is suggested in order to model the interface between wall and core regions and it was analyzed in time and frequency domains; amplitude, velocity and wavelength at each pair transmitter-receiver of the sensor were studied. Correlations for the interfacial structure velocity were found for dispersed oil-in-water flow and unstable-annular flow
Doutorado
Explotação
Doutora em Ciências e Engenharia de Petróleo
CAPES
32
Barone, Marcelo Aiolfi. "Análise experimental sobre a utilização de sensores infravermelhos em provadores de vazão de fluidos claros." Universidade Federal do Espírito Santo, 2012. http://repositorio.ufes.br/handle/10/6231.
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Este trabalho utiliza um protótipo de escala laboratorial do medidor primário pipe prover de modo a avaliar a sua conformidade com os requisitos estabelecidos por normas técnicas e examinar a incerteza da medição da vazão realizados, além de verificar a reprodutibilidade das medições, testes com esferas de diferentes diâmetros, a influência de parâmetros operacionais tais como a variação da pressão de operação e comparação com o teste gravimétrico. O protótipo é feito de tubos plástico com dimensões definidas estatisticamente. Dentro do tubo, uma esfera de elastômero interferente é impulsionada por um escoamento fornecido por uma bomba centrífuga. O sistema de detecção usa sensores de luz infravermelha capaz de detectar a passagem das esferas sem causar interferência ou bloqueio na tubulação. O sistema de aquisição de dados é automático e registra o tempo de trânsito da esfera através de cada pulso de sinal detectado bem como os pulsos gerados por um medidor calibrado tipo turbina, como comparação da avaliação das incertezas de processo utilizando o desempenho da técnica dos sensores infravermelhos
The work uses a laboratory scaled prototype of primary pipe prover flowmeter in order to assess conformity with the requirements established by technical standards and examine the uncertainties of flow measurement performed, besides to check the reproducibility of measurements, tests with spheres of different diameters, the influence of operating parameters such as operating pressure variation and comparison with gravimetric test. The prototype is plastic tubing and considering statically defined dimensions. Inside tubing, an interfering elastomer sphere is driven by flow provided by a centrifugal pump. The detection system uses infrared light sensors able to detect the spheres passage causing pipeline interference or blockage. The acquisition data system is automatic and records the sphere transit time through each pulse signal detected as well as the pulses generated by a calibrated turbine meter, as comparison of the evaluation of process uncertainties using the technique performance with infrared sensors
33
Blaney, S. "Gamma radiation methods for clamp-on multiphase flow metering." Thesis, Cranfield University, 2008. http://dspace.lib.cranfield.ac.uk/handle/1826/5655.
Full textAbstract:
The development of a cost-effective multiphase flow meter to determine the individual
phase flow rates of oil, water and gas was investigated through the exploitation of a
single clamp-on gamma densitometer and signal processing techniques. A fast-sampling
(250 Hz) gamma densitometer was installed at the top of the 10.5 m high, 108.2 mm
internal diameter, stainless steel catenary riser in the Cranfield University multiphase
flow test facility. Gamma radiation attenuation data was collected for two photon
energy ranges of the caesium-137 radioisotope based densitometer for a range of air,
water and oil flow mixtures, spanning the facility’s delivery range.
Signal analysis of the gamma densitometer data revealed the presence of quasi-periodic
waveforms in the time-varying multiphase flow densities and discriminatory
correlations between statistical features of the gamma count data and key multiphase
flow parameters.
The development of a mechanistic approach to infer the multiphase flow rates from the
gamma attenuation information was investigated. A model for the determination of the
individual phase flow rates was proposed based on the gamma attenuation levels; while
quasi-periodic waveforms identified in the multiphase fluid density were observed to
exhibit a strong correlation with the gas and liquid superficial phase velocity parameters
at fixed water cuts.
Analysis of the use of pattern recognition techniques to correlate the gamma
densitometer data with the individual phase superficial velocities and the water cut was
undertaken. Two neural network models were developed for comparison: a single
multilayer-perceptron and a multilayer hierarchical flow regime dependent model. The
pattern recognition systems were trained to map the temporal fluctuations in the
multiphase mixture density with the individual phase flow rates using statistical features
extracted from the gamma count signals as their inputs. Initial results yielded individual
phase flow rate predictions to within ±10% based on flow regime specific correlations.
34
Imada, Fabiano Hikoji Jorge. "Estudo da estrutura multidimensional de escoamentos multifásicos em dispositivos de medição de pressão diferencial." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3150/tde-19032015-171034/.
Full textAbstract:
A medição de vazão de escoamentos multifásicos é uma necessidade constante em diversas atividades industriais como exploração de óleo e gás, controle de linhas de transporte de vapor e monitoramento de sistemas de resfriamento de usinas nucleares. Dentre os meios disponíveis para a realização da medição de vazão mássica, os dispositivos de medição de pressão diferencial constituem um dos métodos mais simples, sendo sua construção, aplicação e operação em escoamentos monofásicos bem conhecidas e definidas por normas técnicas. No entanto, sua aplicação tem sido estendida a escoamentos multifásicos, geralmente estando aliada a uma técnica adicional de medição de fração de vazio ou fração volumétrica das fases. Este trabalho descreve o estudo numérico de escoamentos multifásicos através de medidores de vazão baseados em pressão diferencial como placas de orifício e bocais de vazão de raio longo. Para tal, primeiramente foram conduzidas simulações de escoamentos monofásicos através de placas de orifício e bocais de vazão de raio longo na faixa de número de Reynolds 15.000 500.000. Os resultados de coeficiente de descarga obtidos foram quantitativamente comparados com os valores preditos por norma ISO, apresentando desvio máximo de aproximadamente 4, 9% para as placas e de 1,0% para os bocais. Em uma segunda etapa, escoamentos do tipo gás úmido (wet gas) através de placas de orifício foram simulados através de três abordagens diferentes. Os resultados de vazão mássica total obtidos foram comparados com dados experimentais fornecidos pela PETROBRAS. As abordagens que consideram o escorregamento entre as fases apresentaram previsões mais próximas dos experimentos, com desvio relativo médio de 3,9%, enquanto a modelagem homogênea apresentou um desvio médio de 6, 6%. Nestes estudos, foram também avaliadas as estruturas desenvolvidas no escoamento através de visualizações da distribuição de fases. São também apresentadas duas sugestões para complementação da caracterização de um escoamento multifásico: (1) a introdução da informação de fração de vazio na formulação apresentada por Paz (2011) e (2) a análise estatística do sinal de pressão diferencial em placas de orifício. Com relação ao primeiro item, comparações quantitativas com dados experimentais sugeriram que a alternativa apresentada é viável para operações de monitoramento da produção. Já o último estudo mostrou qualitativamente a influência da quantidade de líquido na flutuação da pressão diferencialThe flowrate measurement of multiphase flows is a constant need at many industrial activities such as oil and gas exploration, steam transport lines control and monitoring of nuclear plants cooling systems. Within the available means for performing flowrate measurement, the differential pressure devices constitute one of the simplest methods, with their construction, application and operation in single phase flows being well known and defined by technical standards. However, their application has been extended to multiphase flows, usually being allied to a void fraction or phase volume fraction measurement technique. This work describes a numerical study of multiphase flows through differential pressure-based flowrate meters such as orifice plates and long radius nozzles. Firstly simulations of single phase flows through orifice plates and long radius nozzles were conducted in the Reynolds number range 15.000500.000. The obtained results of discharge coefficients were quantitatively compared to ISO Standard predicted values, showing a maximum deviation of approximately 4,9% for the orifice plates and of 1,0% for the nozzles. In a second stage, wet gas flows through orifice plates were simulated by means of three approaches. The calculated results of total mass flowrate were compared to experimental data provided by PETROBRAS. The approaches that considered the slip between phases provided the closest results to the experiments, with a mean relative error of 3, 9%, while the homogeneous modeling presented an error of 6, 6%. In these studies, the structures developed within the domain were also evaluated through the visualization of the phases distribution. Two suggestions for complementing the characterization of a multiphase flow are presented: (1) the introduction of void fraction information into the formulation presented by Paz (2011) and (2) the statistical analysis of the orifice plate pressure drop signal. Regarding the first item, quantitative comparison with experimental data suggested that the presented alternative is viable for production monitoring operations. The last study qualitatively revealed the influence of the liquid loading in the pressure drop fluctuation.
35
Libert, Nikolas. "Sistema de medição capacitivo para determinação da fração de vazio em escoamentos bifásicos." Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/595.
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CAPESAlém de estarem presentes na natureza, os escoamentos bifásicos possuem ampla aplicação industrial, sendo encontrados nas áreas química, nuclear, de geração de energia, petrolífera e espacial, onde escoamentos do tipo gás-líquido são os mais comuns. Eles são caracterizados pelo fluxo de duas substâncias imiscíveis, denominadas fases, em um sistema. A caracterização e o estudo destes escoamentos são importantes tanto na realização de projetos, quanto no monitoramento e controle de plantas aonde eles ocorrem. Um dos parâmetros utilizados na caracterização é a fração de vazio, que indica a proporção de gás em escoamentos gás liquido. As fases de um escoamento possuem diferentes propriedades elétricas, como condutividade e permissividade. Dessa forma, caso placas condutoras sejam dispostas ao redor de uma tubulação, pode ser formado um capacitor cuja capacitância dependa das características da mistura que escoa. O objetivo desta dissertação é o desenvolvimento de um sensor capacitivo não invasivo para determinação de fração de vazio em escoamentos bifásicos. Este trabalho apresenta a montagem dos eletrodos, o desenvolvimento de um hardware para detecção de variações na capacitância dos eletrodos e o desenvolvimento de um software para leitura das medições do hardware. A resposta do sensor desenvolvido não depende apenas da proporção volumétrica das fases em seu interior, mas também do padrão de escoamento, ou seja, da forma como elas estão distribuídas. Devido a isso, a resposta do sensor foi avaliada para diversos padrões de escoamento através de simulações do campo elétrico pelo método dos elementos finitos. Com base nos resultados das simulações e nas medidas da eletrônica desenvolvida, valores de fração de vazio foram obtidos para escoamentos ar água em bancadas de teste. Resultados obtidos mostram o bom desempenho do sistema capacitivo desenvolvido, o qual pode ser aplicado em estudos aprofundados do escoamento bifásico.
Two-phase flows are not only present in environmental phenomena such as clouds, but are found widespread in industrial applications. Such flows may be described as the stream of two immiscible substances, called phases, in a pipe or vessel. Most usual type of flow is gas-liquid flow and it can be found in chemical, nuclear, power generation, petroleum, and space industry. The study and characterization of such flows are important both in the realization of projects as in the monitoring and control of the facilities in which they occur. An important parameter in flow characterization is the void fraction, which indicates the volumetric amount of gas in gas-liquid flows. The gaseous and liquid phases in a flow usually present different electric properties, such as conductivity and permittivity. If electrodes are arranged around a pipe, they may form a capacitor whose capacitance depend upon the flowing mixture properties and their spatial distribution. The main goal of this work is to develop a non-invasive capacitive probe for void fraction determination in two-phase flow. It describes the assembly of the electrodes, the development of hardware for capacitance measurement, and the development of software that provides access to the measurement data obtained by the hardware. The response of capacitive sensors depends not only on void fraction values, but also on the flow pattern, that is, on the way that phases are distributed inside the pipe. Due to this fact, electric field simulations of the sensor’s response at different flow patterns were performed. Based on the results of the simulations and on the measurement results, void fraction values for air-water flow at controlled conditions was calculated and comparatively evaluated. The results obtained show the good performance of developed capacitive probe which may now be deployed in two-phase flow studies.
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Zhang, Jian-Bo. "Turbulence measurements in shallow shear flow using video imaging method." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34487.
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Quasi-two-dimensional turbulent flows were produced in a tank of small thickness to study confinement and friction effects on large-scale turbulent motion of small depth. The tank was constructed of two parallel walls. The space between the walls (4.4 cm, 1.57 cm and 0.59 cm) was small compared with the height (108 cm) and the width (210 cm) of the tank, and was varied during the experiments for different confinement and friction effects. Two series of experiments were conducted. In the first series turbulent flows were produced by the injection of water in the form of shallow jets into the tank filled with water of the same density. In the second series turbulent flows in the form of shallow plumes were produced by releasing saline solution from a line source, located at the top of the tank, into the tank filled with water. Dye was injected with the source fluid as the tracer. The concentration of the dye in the shallow turbulent flows was determined using a video imaging technique. From the initiation of the turbulent motion at the source to the final interaction of the jets and the plumes with the tank, the entire sequence of events was recorded by a video camera. The unsteady turbulent motions were analyzed using the recorded video images. The large-scale turbulent flow in the small space between the walls of the tank is confined to essentially two-dimensional motion, and the motion is retarded by the force of friction. The confinement effect was evaluated from the data of the shallow plume experiments, as the friction effect is neglible compared with the buoyancy effect in the case of the plume. Friction, however, is significant in the case of the jet. The effect of the friction, evaluated from the data of the shallow jet experiments, was found to have a profound effect on the entrainment processes. These findings are useful for turbulent modelling of the shallow shear flow and on its application to the large scale heat and mass exchange processes in the atm
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Zhang, Jian-Bo. "Turbulence measurements in shallow shear flow using video imaging method." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30427.pdf.
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Gray, Callum. "The development of particle image velocimetry for water wave studies." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/13946.
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Azzouz, Ali. "Conception d'un thermoanemometre et application a l'evaluation des transferts thermiques lors de l'ouverture d'une chambre froide industrielle." Paris, CNAM, 1988. http://www.theses.fr/1988CNAM0096.
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Les pertes thermiques d'une chambre froide s'ouvrant par glissement lateral sont mesurees a l'aide d'un thermoanemometre a fil chaud, ayant seize capteurs de mesure de la vitesse du courant d'air. Les resultats experimentaux sont correles par une loi qui exprime le debit massique en fonction de l'ecart de temperature. Des rideaux d'air protecteurs sont experimentes. Ils permettent un gain de 38% sur le debit massique d'air chaud entrant en chambre froide
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Mitchem, Charles E. Jr. "A Comparative Study of Stream-Gaging Methods Employed in Nonpoint Source Pollution Studies in Small Streams." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/9761.
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The U.S. Geological Survey started measuring stream flow in 1888 as part of a public land irrigation study. The demand for accurate stream flow measurement has increased with the rising concern about nonpoint source (NPS) pollution. NPS pollution studies, such as TMDL development, often involve quantification of flow in small first and second order streams. This application of technology intended for use in larger streams presents special problems that must be addressed by the user.
The goal of this study was to conduct a comparative analysis of the current technologies used to measure flow in small streams with respect to accuracy and cost. The analyses involved field investigations, laboratory experiments, and a cost analysis. The specific study objectives were: 1) Compare the accuracy of various methods for estimating stream discharge in small first and second order streams, 2) Compare the accuracy of various methods for estimating stream discharge in a controlled laboratory environment, and 3) Evaluate the costs associated with installation, operation, and maintenance of each of the systems investigated.
Ten stream-gaging methods were evaluated for their field performance, laboratory performance, and costs. Analysis of the field investigation data indicated that the Marsh McBirney current meter and the One-orange method were the most accurate among the methods studied. The results of the laboratory experiments imply that the Starflow acoustic Doppler and Valeport BFM001 current meter performed best among the ten methods. The Starflow acoustic Doppler device also proved to be the most cost-effective method. Overall, the Marsh McBirney and Valeport BFM001 current meters exhibited the best performance for both field and laboratory situations among the methods evaluated.Master of Science
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Collin, Marie-France. "Analyse quantitative de visualisations d'écoulements par la mise au point d'une méthode de traitement d'images : application à la détermination du champ des vitesses." Poitiers, 1989. http://www.theses.fr/1989POIT2270.
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Developpement et essai d'une chaine de traitement et d'analyse d'images pour l'exploitation des cliches de visualisation d'ecoulement, obtenus par la technique des traceurs solides. Analyse des images numerisees par une methode de codages de contour. On considere la configuration des traces. Les traces juxtaposees sont identifiees et segmentees. Application a 4 cliches visualisant la brusque mise en translation d'un profil naca0012 en incidence fixe
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Jouette, Christian. "Conception d'un appareil de mesure du débit sanguin tissulaire par effet doppler optique : choix des paramètres d'échantillonnage et d'analyse spectrale, et détermination d'un indice débit métrique." Nancy 1, 1994. http://www.theses.fr/1994NAN10106.
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La mesure du débit sanguin tissulaire par effet doppler optique est une idée séduisante. L'utilisation d'une source laser, par la cohérence spatiale et géométrique qu'elle offre, en simplifie la réalisation pratique. La vitesse des différentes composantes, notamment les hématies, n'est pas uniforme. Il en résulte donc une distribution spectrale image de cette répartition. De plus, l'environnement du faisceau laser étant constitué par de la matière vivante, de nombreux paramètres influencent les résultats. Dans un premier temps, nous décrivons l'évolution des doppler-lasers, et nous exposons les problèmes qu'ils soulèvent. Ceci nous amène à considérer ensuite, que seule une étude fine du spectre peut nous conduire à un appareil fiable et réellement utilisable en routine. Nous présentons ici un doppler-laser à traitement numérique. La distribution spectrale est calculée par un processeur de signaux numérique (dsp) grâce à un algorithme de transformée de Fourier rapide. Nous donnons les paramètres caractéristiques qui nous paraissent optimaux, et relevons les difficultés qui subsistent avant de pouvoir réaliser un système performant
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Hann, David Brian. "Simultaneous measurement of acoustic fields and flow fields using optical methods." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/14985.
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Two different optical techniques are applied to the measurement of the acoustic particle velocity in velocity fields. Firstly, the measurement of both the acoustic particle velocity and the mean flow velocity using Laser Doppler Anemometry is described. Secondly, the Particle Image Velocimetry method is investigated to determine the possibility of measuring the acoustic particle velocity and then both the acoustic particle velocity and the mean flow velocity. For the first case, consideration is given to the conditions necessary to obtain both of these parameters. The theory was then developed to allow the analysis of the Laser Doppler Anemometry signal. Experiments are then described which test the technique and some successful measurements are made. In the second case, the conditions for the use of Particle Image Velocimetry is discussed and the theory is developed. The theory is compared against computationally constructed images in order to test the range and accuracy of the possible ways of doing the measurement. Experiments are then done which show that the measured values agree well with the Theory.
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Amailland, Sylvain. "Caractérisation de sources acoustiques par imagerie en écoulement d'eau confiné." Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1037/document.
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Les exigences en matière de bruit rayonné par les navires de la Marine ou de recherche engendrent le développement de nouvelles méthodes pour améliorer leurs caractérisations. Le propulseur, qui est la source la plus importante en champ lointain, est généralement étudié en tunnel hydrodynamique. Cependant, compte tenu de la réverbération dans le tunnel et du niveau élevé du bruit de couche limite turbulente (CLT), la caractérisation peut s’ avérer délicate. L'objectif de la thèse est d'améliorer les capacités de mesures acoustiques du Grand Tunnel Hydrodynamique (GTH) de la DGA en matière de bruits émis par les maquettes testées dans des configurations d'écoulement.Un modèle de propagation basé sur la théorie des sources images est utilisé afin de prendre en compte le confinement du tunnel. Les coefficients de réflexion associés aux parois du tunnel sont identifiés par méthode inverse et à partir de la connaissance de quelques fonctions de transfert. Un algorithme de débruitage qui repose sur l’ Analyse en Composantes Principales Robuste est également proposé. Il s'agit de séparer, de manière aveugle ou semi-aveugle, l’ information acoustique du bruit de CLT en exploitant, respectivement, la propriété de rang faible et la structure parcimonieuse des matrices interspectrales du signal acoustique et du bruit. Ensuite, une technique d'imagerie basée sur la méthode des sources équivalentes est appliquée afin de localiser et quantifier des sources acoustiques corrélées ou décorrélées. Enfin, la potentialité des techniques proposées est évaluée expérimentalement dans le GTH en présence d'une source acoustique et d'un écoulement contrôléThe noise requirements for naval and research vessels lead to the development of new characterization methods. The propeller, which is the most important source in the far field, is usually studied in a water tunnel. However, due to the reverberation in the tunnel and the high level of flow noise, the characterization may be difficult. The aim of the thesis is to improve the measurement capabilities of the DGA Hydrodynamic tunnel (GTH) in terms of noise radiated by models in flow configurations.The propagation model is described through the image source method. Unfortunately, the reflection coefficients of the tunnel walls are generally unknown and it is proposed to estimate these parameters using an inverse method and the knowledge of some reference transfer functions. The boundary layer noise (BLN) may be stronger than the acoustic signal, therefore a Robust Principal Component Analysis is introduced in order to separate, blindly or semi-blindly, the acoustic signal from the noise. This algorithm is taking advantage of the low rank and sparse structure of the acoustic and the BLN cross-spectrum matrices. Then an acoustic imaging technique based on the equivalent source method is applied in order to localize and quantify correlated or decorrelated sources. Finally, the potentiality of the proposed techniques is evaluated experimentally in the GTH in the presence of an acoustic source and a controlled flow
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Novak, Matej. "Quantitative methods for the measurement and monitoring of mixing flows using a computer vision system." Thesis, University of Hertfordshire, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369766.
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Brown, Gregor J. "Development and modelling of ultrasonic methods for flow measurement in oil production pipelines." Thesis, Glasgow Caledonian University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404654.
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Alshawaf, Hussain M. J. A. A. M. A. "A Novel Thermal Method for Pipe Flow Measurements Using a Non-invasive BTU Meter." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/101528.
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This work presents the development of a novel and non-invasive method that measures fluid flow rate and temperature in pipes. While current non-invasive flow meters are able to measure pipe flow rate, they cannot simultaneously measure the internal temperature of the fluid flow, which limits their widespread application. Moreover, devices that are able to determine flow temperature are primarily intrusive and require constant maintenance, which can shut down operation, resulting in downtime and economic loss. Consequently, non-invasive flow rate and temperature measurement systems are becoming increasingly attractive for a variety of operations, including for use in leak detection, energy metering, energy optimization, and oil and gas production, to name a few. In this work, a new solution method and parameter estimation scheme are developed and deployed to non-invasively determine fluid flow rate and temperature in a pipe. This new method is utilized in conjunction with a sensor-based apparatus--"namely, the Combined Heat Flux and Temperature Sensor (CHFT+), which employs simultaneous heat flux and temperature measurements for non-invasive thermal interrogation (NITI). In this work, the CHFT+ sensor embodiment is referred to as the British Thermal Unit (BTU) Meter. The fluid's flow rate and temperature are determined by estimating the fluid's convection heat transfer coefficient and the sensor-pipe thermal contact resistance. The new solution method and parameter estimation scheme were validated using both simulated and experimental data. The experimental data was validated for accuracy using a commercially available FR1118P10 Inline Flowmeter by Sotera Systems (Fort Wayne, IN) and a ThermaGate sensor by ThermaSENSE Corp. (Roanoke, VA). This study's experimental results displayed excellent agreement with values estimated from the aforementioned methods. Once tested in conjunction with the non-invasive BTU Meter, the proposed solution and parameter estimation scheme displayed an excellent level of validity and reliability in the results. Given the proposed BTU Meter's non-invasive design and experimental results, the developed solution and parameter estimation scheme shows promise for use in a variety of different residential, commercial, and industrial applications.MS
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Alves, Cristina Consolado Santos. "Métodos e medições de caudais. Análise e comparação de diversos métodos hidrométricos." Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/3945.
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Mestrado em Engenharia do Ambiente - Instituto Superior de AgronomiaIn Portugal there are numerous water resources, water potential distributed mainly in small and medium rivers. There is urgent need of quantifying and managing these resources. The Division of Water Resources INAG, is responsible for managing the hydrometric network in the country, for decades the work of hydrometry is developed, naturally over time the technological evolution of tools and techniques for measuring the quantities involved the hydraulic phenomena. For decades the technologies for measuring water velocity and calculation methods have been refurbished. Nowadays there is a wide variety of equipment with different features and functionalities, for the method of measurement and calculation of flow. For a proper quantification management of water resources is essential, flow measurements in various streams, with the knowledge of these values and their evolution over time, it is possible to determine a flow curve, which is representative of the flow at a given period of time. This work has as objective an analysis to historical data relating to joint measurements of water depth and corresponding flow, the traditional method, which was used by INAG in order to get their flow curves. Also covered are the different flows measuring devices and comparison between the latest electromagnetic and Stream Pro.
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山本, 和弘, Kazuhiro YAMAMOTO, 泰樹 西澤, Yasuki NISHIZAWA, 義昭 小沼, and Yoshiaki ONUMA. "旋回噴流燃焼器を用いた強乱流予混合火炎の研究 (第3報, Slot-Correlation法による燃焼場の乱れスケールの計測)." 日本機械学会, 2002. http://hdl.handle.net/2237/9348.
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Fällman, Monika Carina. "Turbulence measurements in fiber suspension flows : experimental methods and results." Licentiate thesis, KTH, Mechanics, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11460.
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Turbulent mixing is present in many pulp and paper processes. It is a particularly important factor in the design and improvements of the paper machine headbox, influencing the final paper structure. During this project, experimental methods to quantify the effect of fibers on turbulent suspension flows have been developed, and then used for studying turbulent mixing in fiber suspensions. A technique that uses microprobes to measure passive scalar mixing of salt for the characterization of turbulent fluctuations in a fiber suspension flow has been developed: Conductivity micro-probes have been built and turbulence measurements have been performed in simple jet and wake flows, studying turbulent mixing between the two streams of pulp suspension, of which one has been doped with salt. A relatively new technique to measure fluid velocity non-intrusively in opaque fluids has also been tested. The technique makes use of ultrasonic pulses to obtain velocity information through the Doppler-shift of reflected pulses. The main efforts reported on in the thesis are focused on method design and development as well as method evaluation.