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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.
101

Avaliação do desempenho de um medidor de vazão eletromagnetico em situações praticas reais de instalação / Evaluation of the performance of an electromagnetic flowmeter in real practical situations of installation

Martim, André Luís Sotero Salustiano, 1976- 24 February 2005 (has links)
Orientador: Ana Ines Borri Genovez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-06T04:58:32Z (GMT). No. of bitstreams: 1 Martim_AndreLuisSoteroSalustiano_M.pdf: 5209979 bytes, checksum: cd531521e2ae52a28d5dcfc9952e9dd2 (MD5) Previous issue date: 2005 / Resumo: Martim, André Luís Sotero Salustiano. Avaliação do Desempenho de um Medidor de Vazão Eletromagnético em Situações Práticas Reais de Instalação. Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo, Universidade Estadual de Campinas, 2005. 182 páginas. Dissertação. A busca do melhor aproveitamento dos recursos hídricos é uma característica permanente nas políticas atuais, e o gerenciamento de recursos hídricos implica no equacionamento entre a vazão disponível e a vazão de demanda, ou seja, na medição de vazão. A partir de 2004 os usuários de recursos hídricos são obrigados a declarar os volumes de água captados, é a declaração anual de uso de recursos hídricos. A qualidade da vazão medida depende das técnicas de medição, e um dos principais fatores intervenientes é a condição de instalação do medidor. A avaliação de um medidor eletromagnético de vazão em condições práticas de instalação foi desenvolvida experimentalmente neste trabalho. O medidor de vazão eletromagnético utilizado foi instalado em quatro situações diferentes e os valores de vazão obtidos foram comparados com os de dois medidores instalados adequadamente, um medidor Venturi e um medidor Ultra-sônico. Os ensaios foram desenvolvidos em uma bancada no Laboratório de Hidráulica e Mecânica dos Fluidos da Faculdade de Engenharia Civil da Unicamp. Para a configuração com o medidor eletromagnético instalado à jusante de uma curva 900 de raio curto, o desvio máximo foi de 0,742% com uma incerteza de 0,27%. Para a configuração com o medidor eletromagnético instalado à jusante de duas curvas 900 de raio curto, o desvio máximo foi de 0,447% com uma incerteza de 0,74%. Para a configuração com o medidor eletromagnético instalado à jusante de uma válvula de gaveta, com 50% de abertura, o desvio máximo foi de -2,046% e uma incerteza de 0,50%. Os resultados obtidos mostram claramente que a condição de instalação do medidor frente às singularidades da tubulação afetam sua performance. Os valores de desvio de indicação podem ser considerados baixos ou altos, dependendo da exatidão exigida do medidor dentro do sistema / Abstract: Martim, André Luís Sotero Salustiano. Evaluation of the performance of an electromagnetic flowmeter in real practical situations of installation. Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo, Universidade Estadual de Campinas, 2005. The search of the best utilization of the water resources is a permanent characteristic in the current politics, and the management of water resources implies in the balance equally between the available flow and the flow of demand, or either, in the flow measurement. From 2004 the users of water resources are obliged to declare the caught volumes of water, is the annual declaration of use of water resources. The quality of the measured flow depends on the measurement techniques, and one of the main intervening factors is the condition of installation of the flowmeter. The evaluation of an electromagnetic flowmeter in practical conditions of installation was developed experimentally in this work. The electromagnetic flowmeter was installed in four different situations and the gotten values of flow measurement had been compared with the ones of two flowmeters installed adequately, an Venturi fi owmete r and an Ultrasonic flowmeter. The evaluation had been developed in a work-bench in the Laboratory of Hidraulical and Mechanic of fluid of the College of Civil Engineering of the Unicamp. For the configuration with the electromagnetic flowmeter installed downstream of a 90° elbow of short ray, the maximum deviation was of 0,742% with a 0,27% uncertainty. For the configuration with the electromagnetic flowmeter installed downstream of a two 90° elbow of short ray, the maximum deviation was of 0,447% with a 0,74% uncertainty. For the configuration with the installed electromagnetic flowmeter downstream a drawer valve, with 50% of opening, the maximum deviation was of a -2,046% and uncertainty of 0,50%. The gotten results show clearly that the condition of installation of the flowmeter front to the singularity of the tubing affects its performance. The values of deviation indication can be considered low or high, depending on the demanded accuracy of the flowmeter inside of the system / Mestrado / Recursos Hidricos / Mestre em Engenharia Civil
102

Estudo experimental e modelagem matemática de ondas no escoamento estratificado óleo-água em tubulação levemente inclinada / Experimental study and mathematical modeling of waves in slightly-inclined oil-water stratified pipe flow

Diego Oliveira de Mello 08 October 2007 (has links)
Embora o escoamento estratificado óleo-água seja comum na indústria do petróleo, existem poucos trabalhos na literatura sobre a estrutura ondulatória encontrada no escoamento em dutos ascendentes ou descendentes. O objetivo deste trabalho é entender e caracterizar as estruturas interfaciais ondulatórias em escoamentos estratificados óleo e água em dutos levemente inclinados e comparar com os resultados retirados da modelagem proposta. Uma primeira tentativa de modelar a onda interfacial óleo-água através da equação da energia bifásica unidimensional para regime permanente é apresentada e comparada aos resultados obtidos experimentalmente. Valores de comprimento de onda foram coletados para quatro ângulos de inclinação a partir da horizontal (-5º, -2º, 2º e 5º) e diversos pares de vazão de óleo e água. Os dados foram extraídos de frames de vídeos de alta resolução através de uma técnica manual. Um software baseado em LabView foi desenvolvido para possibilitar a automação da obtenção do comprimento de onda e amplitude. Os comprimentos de onda obtidos com a técnica automática foram comparados com os dados obtidos através da técnica manual. O mensuramento é bem satisfatório e sugere que a ferramenta experimental proposta possa ser aplicada para o estudo de qualquer padrão de escoamento óleo-água, onde uma estrutura ondulatória possa ser identificada. A validade da modelagem da onda interfacial proposta foi avaliada através da comparação entre os resultados teóricos e dados experimentais. A concordância observada é encorajadora. / Even though the oil-water stratified flow pattern has a common occurrence in the upstream oil industry, quite often in directional wells, there are only a few works in the literature dealing with its interfacial wavy structure. This work has the mean goal of comprehending a characterizing the interfacial wave structure in inclined water-oil stratified pipe flow, comparing it with the proposed model. A model, based on the steady-state one-dimensional two-phase flow energy equation is presented and compared to our experimental data. Wave lengths and amplitude data were collected at four inclinations from the horizontal (-5º, -2º, 2º and 5º) and several oil and water flow rates. The data were extracted form high-resolution video images through a manual technique. A LabView based software was developed in order to obtain the lengths and amplitude automatically. Wave length obtained from it were compared to the manual technique data. The satisfactory measurement suggests the applicability of the experimental tool to any water-oil pipe flow pattern, where a wave structure can be identified. The validity by the comparison between theoretical and experimental data. The agreement observed is promising.
103

Estudo experimental e modelagem do escoamento estratificado ondulado óleo-água / Experimental study and modeling of wavy oil-water stratified pipe flow

Cléber Carvalho Pereira 18 March 2011 (has links)
O escoamento estratificado óleo-água é bastante comum na indústria do petróleo, especialmente em poços direcionas offshore, oleodutos e gasodutos. Entretanto, existem poucos trabalhos na literatura sobre a natureza da estrutura ondulatória observada no escoamento em dutos ascendentes ou descendentes a partir da horizontal. O objetivo deste trabalho foi estudar as propriedades geométricas e cinemáticas da onda interfacial, i.e, forma média, comprimento, amplitude e celeridade, e assim contribuir para a compreensão do papel da onda interfacial na dinâmica do escoamento estratificado. Um software baseado em plataforma Labview® possibilitou a automação para obtenção dos dados das ondas interfaciais extraídas de imagens de vídeos de alta resolução. Além das propriedades das ondas, também se coletaram valores de fração volumétrica in situ e de gradiente de pressão bifásico para cinco ângulos de inclinação (-20°, -10°, 0°, 10° e 20°) em diferentes pares de vazões de óleo e água. Desenvolveu-se um modelo fenomenológico considerando os termos ondulatórios do escoamento para o cálculo da fração volumétrica in situ e do gradiente de pressão bifásico, sendo comparado com modelos disponíveis na literatura e dados experimentais. A concordância do modelo proposto com os dados coletados neste trabalho se mostrou muito boa, o que sugere um avanço em comparação ao existente na literatura. O estudo da equação da onda de perturbação interfacial para o escoamento estratificado óleo-água indicou que a natureza da onda observada é cinemática e não dinâmica; e baseado na equação da celeridade da onda cinemática pode-se confrontar a celeridade experimental com a teórica, revelando boa concordância. / The oil-water stratified flow is quite common in the oil industry, especially in offshore directional wells and pipelines. However, there are few studies on the physics of the wavy structure observed in upward and downward stratified flow. The goal of this work was to study the geometric and kinematic properties of interfacial waves, i.e., the average shape, wavelength, amplitude and celerity. A homemade Labview®-based software enabled the automatic acquisition of data extracted from frames obtained via high resolution video recording. In situ volume fraction and two-phase pressure gradient data for five inclination angles (-20°, -10°, 0°, 10° and 20°) at several pairs of oil and water flow rates were also collected. A phenomenological model that takes into account the wavy structure is proposed to calculate volume fractions and two-phase pressure gradient and it was compared with available models from the literature and experimental data. The good agreement of the proposed model with the data collected in this study is promising and suggests that it may provide better predictions in comparison with models from the literature. The study of the interfacial perturbation wave equation for stratified flow indicates that the observed waves nature is kinematic and not dynamic; and based on the kinematic wave velocity equation we could compare the experimental celerity with the theoretical one, with good agreement.
104

Estudo topológico de escoamento trifásico óleo-água-ar através de sensor de impedância de resposta rápida do tipo \"wire-mesh\" / Topologic study of three-phase pipe flow by means of fast-response wire-mesh impedance sensor

Hugo Fernando Velasco Peña 27 February 2015 (has links)
A ocorrência frequente de escoamentos multifásicos em tubulações tem motivado um grande interesse acadêmico nas últimas décadas. O caso particular de escoamentos líquidolíquido é geralmente encontrado na indústria do petróleo, onde uma série de aplicações envolve escoamentos óleo-água, tais como a produção de petróleo e seu transporte. No entanto, ele não tem recebido a mesma atenção quando comparado com escoamentos gás-líquido. Ainda não existe uma explicação física razoável para um número significativo de fenômenos observados em escoamento óleo-água, como o fenômeno de redução de atrito, observado em escoamento disperso, e a estrutura interfacial ondulada em escoamento estratificado. Os escoamentos trifásicos têm sido ainda menos estudados. Há técnicas de medição, desenvolvidas para escoamento gás-líquido, que supostamente são adaptáveis aos escoamentos líquido-líquido, mas várias delas ainda precisam de validação adequada. O sensor wire-mesh, um método híbrido baseado na medição de resistência ou capacitância, que combina medição local intrusiva da fração de fase e imagens tomográficas transversais, oferece uma boa resolução espacial e alta resolução temporal em comparação com outras técnicas atuais. Porém, a literatura existente em aplicações do sensor wire-mesh cobre quase apenas o escoamento gás-líquido e, até agora, não é possível avaliar o limite de viscosidade do fluido para a sua aplicação. Neste contexto, este projeto propõe o estudo de aspectos importantes da fenomenologia de escoamentos líquido-líquido e líquido-líquido-gás com o auxílio da tecnologia wire-mesh. O principal objetivo prático é a validação da técnica wire-mesh como ferramenta de referência para o desenvolvimento de instrumentação para aplicações em campos petrolíferos, com especial atenção devotada ao efeito da viscosidade do óleo sobre a confiabilidade da medição e à extensão da tecnologia para lidar com escoamentos óleo-água-gás. / The frequent occurrence of multiphase flows in pipes has motivated a great research interest over the last decades. The particular case of liquid-liquid flow is commonly encountered in the petroleum industry, where a number of applications involve oil-water flow such as crude oil production and transportation. However, it has not received the same attention when compared to gas-liquid flow. There is no reasonable physical explanation for a significant number of phenomena observed in oil-water flow, as the drag reduction phenomenon observed in dispersed flow and the interfacial wavy structure of stratified flow. Much less has been investigated when it comes to three-phase flow. Several measurement techniques that are supposed to be adaptable to liquid-liquid flow have been proposed recently, but many of them still need proper validation. The wire-mesh sensor, a hybrid impedance-based method that combines intrusive local measurement of phase fraction and tomographic cross-sectional imaging, offers good spatial resolution and high temporal resolution in comparison with other current techniques. However, the existing literature on wire-mesh sensor applications covers almost only the gas-liquid flow and, so far, it is not possible to evaluate the fluid-viscosity limit for its application. In that context, this project proposes the study of important aspects of liquidliquid and liquid-liquid-gas flow phenomenology with the aid of the wire-mesh technology. The main goal is the validation of the wire-mesh technique as a reference tool for the development of instrumentation for oilfield application, with especial attention paid to the effect of oil viscosity on measurement reliability and the extension of the technology for dealing with oil-water-gas flow.
105

Subsurface fluxes of mass and energy at the accumulation zone of Lomonosovfonna ice cap, Svalbard

Marchenko, Sergey January 2018 (has links)
Glaciers cover ca 10% of the Earth's land and are found in the high altitudes and latitudes. They are important components of environmental systems due to the multiple feedbacks linking them with the atmosphere, hydrosphere and periglacial landscapes. The cold sloping surfaces of glaciers change the patterns of atmospheric circulation at different scales and at the same time glaciers are largely controlled by climate. They are commonly used as climatic archives for reconstruction of the past environmental changes based on evidences from the areas affected by glaciation at the moment and in the past. Glaciers are the largest fresh-water reservoirs on our planet and runoff thereof significantly affects the global sea level and life in glaciated catchments. However, melt- and rain-induced runoff from glaciers greatly depends on the subsurface conditions which thus need to be taken into account, particularly in a changing climate. This thesis focuses on the processes of subsurface mass and energy exchange in the accumulation zones of glaciers, which are largely driven by the climate at the surface. Results are largely based on empirical data from Lomonosovfonna ice cap, Svalbard, collected during field campaigns in 2012-2017. Observations of subsurface density and stratigraphy using shallow cores, video records from boreholes and radar surveys returned detailed descriptions of the snow and firn layering. The subsurface temperature data collected using multiple thermistor strings provided insights into several subsurface processes. The temperature values measured during three summer seasons were used to constrain the suggested parameterization of deep preferential water flow through snow and firn. The part of data recorded during the cold seasons was employed for an inverse modelling exercise resulting in optimized values of effective thermal conductivity of the subsurface profile. These results are then used to compute the subsurface water content by comparing the simulated and measured rates of freezing front propagation after the melt season in 2014. The field observations and quantitative estimates provide further empirical evidences of preferential water flow in snow/firn packs at glaciers. Results presented in the thesis call for implementation of description of the process in layered models simulating the subsurface fluxes of energy and mass at glaciers. This will result in a better understanding of glacier response to the past and future climatic changes and more accurate estimates of glacier runoff. / Stability and Variations of Arctic Land Ice (SVALI)
106

Relationship of Vaal Dam high water flow and water quality from 1995 to 2010

Du Plessis, Anja 02 May 2012 (has links)
M.Sc. / The Vaal River is the main source of water supply to the central industrial, mining and metropolitan regions of South Africa, and is, therefore, strictly regulated by small dams and weirs. The Vaal Dam is the main regulator of water to the Vaal River and is of great importance as it supplies water for human consumption and also to the industrial powerhouse of South Africa. Situated at the confluence of its major tributaries, namely the Vaal and Wilge Rivers, and straddling the convergence of the borders of Gauteng, Free State and Mpumalanga provinces, the Vaal Dam is approximately 77 km south of Johannesburg. It is South Africa’s second-largest dam in terms of area, and third-largest in terms of volume, and is a key component in South Africa’s water supply infrastructure. Gauteng, as well as the surrounding provinces are reliant on it for their water supply. Water flow fluctuations are deemed to be important as they could negatively impact upon the water quality. Knowledge of the relationship between fluctuating water flows and water quality is important as strategies can then be devised on this basis to improve the freshwater situation of the country, the associated management systems, and treatment technologies. By establishing the nature of the respective relationships between high water flow and the selected water quality parameters, ways could be found of reducing the costs of water quality problems, such as eutrophication. The various relationships between high water flow and the selected water quality parameters of the Vaal Dam that were established during the course of this study are as follows: In terms of pH, the study found that in the event of a decline in the water flow, the pH value increased and the water body became more alkaline. A decrease in water flow was also found to be associated with an increase in EC. An increase in water flow was found to be associated with a decrease in pH, EC and Chlorophyll-a. An increase in water flow up to a certain level was found to be associated with an increase in nitrates, sulphates and COD.
107

Modellering av flöden och syrgasförhållanden i Dannemorasjön och dess tillrinningsområde / Modelling water flow and oxygen content in Lake Dannemorasjön and its catchment area

Stenius, Seija January 2007 (has links)
Det hydrologiska systemet i Dannemorasjöns avrinningsområde, beläget i norra Uppland, är mycket komplicerat och har förändrats genom åren på grund av mänskliga ingrepp. De naturliga sjöarna i området har vid flera tillfällen utsatts för stora sänkningsföretag, vars främsta syfte var att förhindra läckage till gruvan i Dannemora. Sjöarna har under lång tid använts som recipienter för samhällena och industrierna i Dannemora och Österbybruk. I området finns det flera dammar som användes som magasin för kraftproduktion till gruvan och järnhanteringen. Flera av dammarna skapades redan på 1600-talet. Syrgassituationen i Dannemorasjöns avrinningsområde är på många håll ansträngd och problemen har särskilt uppmärksammats för Dannemorasjön, Harvikadammen och Sundbroån men även andra sjöar i området är drabbade. Målsättningen med denna rapport är att kartlägga hydrologin i Dannemorasjöns tillrinningsområde, sammanställa fakta om dammar, vattendomar och genomförda vattenföretag, samt utarbeta ett förslag på förändring av flödesregimen och vattendragens utformning för att förbättra syrgasförhållandena i Dannemorasjön. För att kunna se hur en förändrad flödesregim påverkar syrgasförhållandena i Dannemorasjön har en flödesmodell upprättats för sjöns tillrinningsområde. Huvudsakliga indata har varit observerad specifik avrinning från Vattholma, strax nedströms Dannemorasjön. Till flödesmodellen har en modell som simulerar syrgashalten i Dannemorasjön vintertid kopplats. Simuleringsresultaten visar att en förändrad flödesreglering vintertid kan förbättra syrgassituationen i Dannemorasjön. För att denna regleringsstrategi ska bli effektiv krävs dock större magasineringskapacitet i dammarna eller tillskott av vatten genom t.ex. pumpning. Det framgår även från simuleringsresultaten att en vattenståndshöjning i sjön skulle gagna syrgassituationen under senvintern, dels p.g.a. en ökad total mängd syrgas i sjön vid isläggningen, dels genom en minskad syretäring per volymsenhet. Under vintrar med en lång isperiod samt liten tillrinning blir syrgasförhållandena i sjön extra kritiska. Sådana säsonger räcker det inte med en enskild åtgärd utan det krävs flera samordnade åtgärder för att skapa en acceptabel syrgassituation i sjön. / The hydrological system in the catchment area of Lake Dannemorasjön, in the northern part of Uppland, is very complicated and has been changed many times by human activities. The water level of many lakes in the area has been lowered at several occasions. Most of these operations have been made in order to prevent leakage from Lake Gruvsjön to the mine in Dannemora. Already in the 17th century many of the wetlands were dammed up to be used as water storage for water power production. The power was needed for the mine and iron production in the area. Many lakes have also for a long time been used as recipients for waste water. The oxygen content in the lakes and rivers in the area has frequently been reported as very low, especially in Lake Dannemorasjön, Lake Harvikadammen and the River Sundbroån. The aim of this study is to describe the hydrology in the catchment area of Lake Dannemorasjön, compile facts about the regulated spillways of the reservoirs and water regulation vertictsand to work out a plan for changing the water regime in order to increase the oxygen content in Lake Dannemorasjön during winter. A model that simulates the flow of water within the catchment and to Lake Dannemorasjön was developed. Another model that simulates the oxygen content in Lake Dannemorasjön during ice covered conditions was attached to the waterflow model. The results from the model show that a change in the regulation of the flow to Lake Dannemorasjön can increase the oxygen content in the lake. A prerequisite for the new regulation to be effective is that the storage capacity of Lake Harvikadammen is increased or that additional water is supplied to the dam, for instance by pumping water from Lake Dannemorasjön. It is also clear from the study that a raised water level of the lake would affect the oxygen content in a positive way. The oxygen problem becomes particularly serious during cold Winters with a long lasting ice cover. During such Winters it is not enough with just one measure to prevent oxygen deficit, several different kinds of measures must be undertaken in order to make sure that the oxygen content stays at a reasonably level.
108

Posouzení odtokových poměrů na toku ve správě Povodí Moravy, s.p. / Assessment of runoff conditions on flow in the Morava river basin

Holá, Lucie January 2018 (has links)
The diploma thesis deals with the design of nature close to the flood protection of the city Prostějov at the confluence of the watercourses Romže and Hloučely and the flow Valova (Romže). In canculations there was solved capacity of individual sections and canculation of levels for one-year, five-year and twenty-year flow. For canculations there was used one-dimensional mathematical model HEC-RAS 5.0.3. Determination of roughness of bottom and slopes was based on personal visit. The result of this diploma thesis is evaluation of current state and proposal of a nature close to the flood protection in the individual streams in the city Prostějov. The thesis contains the calculation part and the drawing part documenting the proposed measure.
109

Návrh rozdělovacího objektu na řece Romži / Proposal of the water divider on the river Romže

Blaha, Josef January 2016 (has links)
The diploma thesis deals with the design of the water divider near Prostějov on the Romže River. Divider flows will be transferred into the Hloučela River. Within the thesis, hydraulic calculations of the side spillway were solved according to Bürgel, Pavlosky, Engels, Musterle, Kunštátský, Hager and energy solution methods in the Microsoft Excel spreadsheet and by using the HEC-RAS program as well. The calculations were compared to each other. Geometry of the relief water divider on the Romže River and the related buildings was designed based on the performed calculations. The required function of the relief object is guaranteed by manipulation of designed sluice gate. The study includes the text part with the calculations and the drawing part documenting the implementation of the designed measures.
110

Beitrag zur Identifizierung rheologischer Wechselwirkungen von Kaolinen in wässrigen Systemen

Seffern, Pascal 19 December 2017 (has links)
The present dissertation investigates the flow behavior of concentrated Kaolin slurries and furthermore novel rheological measurement-, analysis-, and assessment procedures for characterizing static and dynamic flow behavior in industrial and research applica- tions. Ten different Kaolins with divergent property profiles were investigated in detail. At first, novel measurement and analysis procedures are presented and the raw material inherent properties are correlated with the resulting flow characteristics. The results describe the structural building and breakdown (in both static and dynamic states) of concentrated Kaolin slurry suspensions with and without deflocculant and also the determination of the point of optimal deflocculant concentration through the develop- ment of a novel analysis method and linking of the parameters to a condition matrix. The results lead to a better understanding of the flow behavior of concentrated Kaolin slurries. Due to the use of a strict measurement protocol with a focus on the elimination of external disturbances on the determination of flow behavior, the phases of dynamic structure construction and destruction (with exclusion of temporal structure effects and vice versa) can be analyzed. It was identified that the construction of particle networks requires less energy than their destruction. Furthermore it could be demonstrated that the occurrence of a transient shear stress peak in kaolin slurries is the cause for the breakdown of an existing particle network and not, as conventionally reported, due to an insufficient measurement time. Moreover, through the combination and modification of two measurement protocols described here, manufacturing companies have a potentially useful tool for composition development and quality control without the necessity of purchasing a highly precise research rheometer.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang / In der vorliegenden Arbeit wird das Fließverhalten von konzentrierten Kaolinsuspensio- nen untersucht und neuartige rheologische Mess-, Analyse- und Bewertungsverfahren zur Charakterisierung der Belastungs- und Zeitabhängigkeit für Industrie- und Forschungsanwendungen vorgestellt. Hierzu wurden zehn Kaoline mit divergierenden Eigenschaftsprofilen untersucht. Zunächst werden neuartige Mess- und Analyseverfahren vorgestellt und die Eigenschaften der Rohstoffe mit den ermittelten Fließcharakteristika korreliert. Die Ergebnisse beschreiben den strukturellen Auf- und Abbau (zeit- und belastungsabhängig) von konzentrierten Kaolinsuspensionen mit und ohne Dispergierhilfsmitteleinsatz und darüber hinaus die Ermittlung der optimalen Dispergierhilfsmittelkonzentration durch Entwicklung einer neuartigen Analyse und Verknüpfung von Parametern an eine Bedingungsmatrix. Die Erkenntnisse tragen zum besseren Verständnis des Fließverhaltens konzentrierter Kaolinsuspensionen bei. Aufgrund der entwickelten Messvorschriften und der darin elementar verankerten Elimination von Störgrößen auf die Ermittlung des Fließverhaltens konnten die Phasen des strukturellen Auf- und Abbaus unter Belastung (unter Ausschluss von temporalen Struktureffekten und umgekehrt) analysiert werden. Es wurde festgestellt, dass die Konstruktion von Partikelnetzwerken weniger Energie benötigt, als deren Destruktion und das Auftreten des Schubspannungshügels auf den Zusammenbruch des Partikelnetzwerkes und nicht, wie allgemein beschrieben auf zu geringe Messzeiten zurück zu führen ist. Darüber hinaus wird der produzierenden Industrie, durch Abwandlung und Kombination zweier Messvorschriften ein Werkzeug zur Versatzentwicklung und Qualitätskontrolle, auch ohne die Notwendigkeit des Erwerbs von hochpräzisen Forschungsrheometern bereitgestellt.:1. Einleitung und Problembeschreibung 1 2. Stand des Wissen 3 2.1. ToneundKaoline.............................. 4 2.1.1. EntstehungvonKaolinen...................... 5 2.1.2. KaolinalsRohstoff ......................... 6 2.1.3. DasMineralKaolinit........................ 6 2.2. BeschreibungderRheologie ........................ 8 2.2.1. DasZwei-Platten-Modell...................... 8 2.2.2. FließverhaltenundModelle .................... 9 2.2.3. Messsgeräte und Systeme für die Messung rheologischer Eigen- schaften ............................... 16 2.2.4. RheometrischeMessmethoden................... 21 2.3. ElektrostatischstabilisierteDispersionen . . . . . . . . . . . . . . . . . 25 2.4. Tonmineral-Wasser-Interaktionen ..................... 28 2.5. FließverhaltenvonKaolindispersionen................... 30 3. Rohstoffuntersuchungen 31 3.1. Reindichtebestimmung ........................... 31 3.2. Partikelgrößenanalyse............................ 32 3.2.1. SedimentationimSchwerefeld ................... 33 3.2.2. Laserbeugungs-Partikelgrößenanalyse . . . . . . . . . . . . . . . 34 3.3. SpezifischeOberfläche ........................... 35 3.4. BestimmungderlöslichenSalze ...................... 36 3.5. Kationenaustauschkapazität ........................ 37 3.6. Röntgenfluoreszenzanalyse ......................... 37 3.7. Röntgenbeugungsanalyse.......................... 38 4. Experimentelle Methodik 40 4.1. NormativeMineralphasenanalyse ..................... 40 ii 4.2. BerechnungderPartikelgrößenverteilung . . . . . . . . . . . . . . . . . 4.2.1. AuswertungnachDingerundFunk ................ 4.2.2. DasRRSB-Modell ......................... 4.3. HerstellungderDispersionen........................ 4.4. RheologischeUntersuchungen ....................... 4.4.1. DasMalvernKinexuspro+ .................... 4.4.2. Messmethode zur Bestimmung der Zeitabhängigkeit . . . . . . . 4.4.3. Messmethode zur Bestimmung der Belastungsabhängigkeit . . . 4.5. AuswertungdesSprungversuches ..................... 4.6. AuswertungderScherratenrampe ..................... 5. Wiederholbarkeit der entwickelten Messregime 6. Anpassung der Messregime an industrielle Bedingungen 6.1. RohrströmungeinerPotenzflüssigkeit ................... 6.2. NachweisderMesssystemfähigkeit..................... 7. Versuchsreihenentwicklung 7.1. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 7.2. Untersuchung des Einflusses des Verflüssigeranteils . . . . . . . . . . . . 8. Ergebnisse und Diskussion 8.1. Einfluss der Rohstoffparameter auf das Fließverhalten . . . . . . . . . . 8.1.1. Einfluss der Partikelgrößenverteilung . . . . . . . . . . . . . . . 8.1.2. EinflussderPGV-Modellparameter ................ 8.1.3. Einfluss der spezifischen Oberfläche auf das Fließverhalten . . . 8.1.4. Einfluss der Rohstoffmineralogie auf das Fließverhalten . . . . . 8.2. Untersuchung des Dispergierhilfsmitteleinfusses . . . . . . . . . . . . . 8.3. UntersuchungdesFeststoffanteileinflusses. . . . . . . . . . . . . . . . . 9. Modellierung der belastungsabhängigen Fließeigenschaften 10.Zusammenfassung und Ausblick Literaturverzeichnis Anhang

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