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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of gamma-ray tomographic techniques in granular flows in hoppers

Nikitidis, Michail S. January 1997 (has links)
The aim of this dissertation is to demonstrate the potential of novel measurement techniques based on the scanning of gamma-ray transmission in the investigation of axially-symmetric flow properties of granular materials in 3D hoppers. Furthermore, the results of the experimental investigations are compared on a strictly quantitative basis with Newtonian Dynamics (i.e. Discrete Element simulations) and Molecular Dynamics (i.e. kinetic gas theory calculations). Measurements were performed using two specially constructed scanner systems of different geometric configuration of gamma-ray sources and detectors(namely parallel and fan beam arrangements respectively). The fan beam scanner has been developed entirely in the Department of Chemical & Process Engineering by the author of this thesis and therefore a significant part of the thesis deals with major points concerning both hardware and software development as well as associated calibration procedures. Gas-phase continuous mono-disperse systems have been studied using (i) the full tomographic imaging technique which is able to produce 3D planar maps of voidage at selected heights of a storage vessel and (ii) the single profile absorptiometric technique capable of producing voidage profiles in both Cartesian and polar coordinates at much faster acquisition rates. Results were compared with earlier Distinct Element numerical simulations showing encouraging agreement in terms of both the absolute values of voidage and their spatial fluctuations as well as the geometric structure of the static and dynamic particle assemblies. Size segregation in air borne binary mixtures have been quantified using the novel dual energy photon technique which is capable of producing solids fraction profiles for each of the individual components of a binary mixture in addition to the voidage profiles. Spatial and temporal data on solids fractions in a binary mixture were analysed using methodology based on statistical mechanics principles which led to the definition of "micro-turbulence" during flow in terms of the self-diffusion velocities of individual solid components. This then allows the calculation of both the self- and mutual-diffusion coefficients used to quantify size segregation. These calculations were also compared with theoretical predictions based on the kinetic gas theory which was found to grossly over-predict the calculated diffusion coefficients in slow-shearing granular flows.
2

4. Workshop "Measurement techniques for stationary and transient multiphase flows", Rossendorf, November 16 - 17, 2000

Prasser, Horst-Michael January 2001 (has links)
In November 2000, the 4th Workshop on Measurement Techniques for Stationary and Transient Multiphase Flows took place in Rossendorf. Three previous workshops of this series were national meetings; this time participants from different countries took part. The programme comprised 14 oral presentations, 9 of which are included in these proceedings in full length. A special highlight of the meeting was the main lecture "Ultrasonic doppler method for bubbly flow measurement" of Professor Masanori Aritomi, Dr. Hiroshige Kikura and Dr. Yumiko Suzuki, which was read by Dr. Hiroshige Kikura. The workshop again dealt with high-resolution phase distribution and phase velocity measurement techniques based on electrical conductivity, ultrasound, laser light and high-speed cinematography. A number of presentations were dedicated to the application of wire-mesh sensors developed by FZR for different applications used by the Technical Universities of Delft and Munich and the Tokyo Institute of Technology. The presentations were in particular: M. Aritomi, H. Kikura, Y. Suzuki (Tokyo Institute of Technology): Ultrasonic doppler method for bubbly flow measurement V. V. Kontelev, V. I. Melnikov (TU Nishny Novgorod): An ultrasonic mesh sensor for two-phase flow visualisation A. V. Duncev (TU Nishny Novgorod): Waveguide ultrasonic liquid level transducers for power generating equipment H.-M. Prasser, E. Krepper, D. Lucas, J. Zschau (FZR), D. Peters, G. Pietzsch, W. Taubert, M. Trepte (Teletronic Ingenieurbüro GmbH), Fast wire-mesh sensors for gas-liquid flows and decomposition of gas fraction profiles according to bubble size classes D. Scholz, C. Zippe (FZR): Validation of bubble size measurements with wire-mesh sensors by high-speed video observation A. Manera, H. Hartmann, W.J.M. de Kruijf, T.H.J.J. van der Hagen, R.F. Mudde, (TU Delft, IRI): Low-pressure dynamics of a natural-circulation two-phase flow loop H. Schmidt, O. Herbst, W. Kastner, W. Köhler (Siemens AG KWU): Measuring methods for the investigation of the flow phenomena during external pressure vessel cooling of the boiling water reactor SWR1000 A. Traichel, W. Kästner, S. Schefter, V. Schneider, S. Fleischer, T. Gocht, R. Hampel (HTWS Zittau/Görlitz - IPM): Verification of simulation results of mixture level transients and evaporation processes in level measurement systems using needle-shaped probes S. Richter, M. Aritomi (Tokyo Institute of Technology): Methods for studies on bubbly flow characteristics applying a new electrode-mesh tomograph
3

[en] PERFORMANCE VERIFICATION METHODOLOGY OF MULTIPHASE FLOW METERS IN ALLOCATION MEASUREMENT IN THE OIL AND GAS INDUSTRY / [pt] METODOLOGIA DE VERIFICAÇÃO DE DESEMPENHO DE MEDIDORES DE VAZÃO DE FLUIDO MULTIFÁSICO NA MEDIÇÃO PARA APROPRIAÇÃO NA INDÚSTRIA DE ÓLEO E GÁS NATURAL

LUIZ OCTAVIO VIEIRA PEREIRA 20 February 2019 (has links)
[pt] O medidor de vazão de fluido multifásico (MM) se desenvolveu impulsionado principalmente pela necessidade da indústria de óleo e gás em medir a vazão da produção dos poços que comumente é composta por petróleo, gás e água. Em outubro de 2015, a Agência Nacional de Petróleo, Gás Natural e Biocombustíveis (ANP) publicou o Regulamento Técnico de Medição de Fluido Multifásico para Apropriação de Petróleo, Gás Natural e Água que apresenta os requisitos através de planos que as empresas operadoras de óleo e gás precisam preparar e submeter para obter a autorização para aplicar o MM na medição para apropriação. Contudo, esse regulamento não especifica a metodologia que deve ser utilizada no denominado plano de verificação de desempenho para avaliar desempenho do MM no campo, cabendo a cada operadora desenvolver a sua metodologia para esse fim e apresentar a ANP. Este trabalho propõe e aplica uma metodologia para verificação de desempenho para MM com resultados de testes realizados em laboratório com fluidos reais e em campo de produção de petróleo e gás. É observado que testes com tempo curto de duração, inferior a 1000 segundos, tendem a gerar incertezas mais elevadas do que testes com longa duração, com mais de 1000 segundos, como os realizados na plataforma. Sendo assim, os resultados de incerteza de medição maiores gerados no laboratório com tempos de integração curtos podem ser considerados mais conservativos que os resultados dos testes realizados na plataforma. / [en] The multiphase flowrate (MM) was driven by the necessity of the oil and gas industry to measure the production flow of the wells that are commonly composed of oil, gas and water. In October 2015, the National Agency for Petroleum, Natural Gas and Biofuels (ANP) published the Technical Regulation for Measurement of Multiphase Fluid for Petroleum, Natural Gas and Water produced, which presents the requirements through plans that oil and gas companies need to prepare and submit for authorization to apply the MM in the measurement for allocation. However, this regulation does not specify the methodology that should be used in the so-called performance verification plan to evaluate the performance of the MM in the field, it being incumbent on each operator to develop its methodology for this purpose and present the ANP. This work proposes and applies a methodology for performance verification for MM with test results performed in the laboratory with real fluids and in oil and gas field. It was observed that short duration tests, below 1000 seconds, tend to generate higher uncertainties than long tests, higher than 1000 seconds, such as those performed on the platform. Thus, the higher measurement uncertainty results generated in the laboratory with short integration times can be considered more conservative than the results of the tests performed in the platform.

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