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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

O futuro hoje: a formação em radiojornalismo  na era da convergência das mídias / -

Galvão Júnior, Lourival da Cruz 19 March 2015 (has links)
\"O futuro hoje: a formação em Radiojornalismo na era da convergência das mídias\" surge da emergência de um novo pensar sobre o processo de formação dos estudantes universitários que, no atual contexto, são preparados para atuar como jornalistas em emissoras de rádio que ultrapassaram a fronteira das ondas eletromagnéticas e se estabeleceram também na internet, onde disponibilizam conteúdos sonoros que convergem com outras expressividades midiáticas. Este trabalho, que é apoiado na interface Comunicação/Educação, assumiu o propósito de analisar a ocorrência, no processo de formação em Radiojornalismo, de ações que vinculem os conteúdos teórico/práticos ministrados à convergência das mídias. O distanciamento entre a formação e a realidade surgiu como hipótese, bem como a possível falta de atividades relacionando o Radiojornalismo e a Convergência das Mídias. A metodologia baseou-se em pesquisa bibliográfica, entrevistas e estudo de casos que verificou a formação em Radiojornalismo nos cursos de Jornalismo oferecidos pelas principais universidades do Brasil e de Portugal, sendo elas, respectivamente: o Departamento de Jornalismo e Editoração da Escola de Comunicações e Artes da Universidade de São Paulo (CJE - ECA/USP) e a Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa (FCSH/UNL). Após empreender as verificações propostas, este estudo constatou que a convergência das mídias não aparece integrada às ações teórico/práticas promovidas pelas disciplinas, no Brasil e em Portugal. Entretanto ficou evidente, nos processos de formação, a ocorrência das convergências tecnológicas e de conteúdos. Conclui-se que tal constatação permite aproximar, de forma parcial, os alunos da realidade na qual o Radiojornalismo mantém-se estabelecido. De outro lado, a falta de propostas que explorem a convergência das mídias nas disciplinas caracterizou-se como desfavorável à formação por não possibilitar, aos estudantes, conhecimento pleno desse fenômeno potencializado pela presença e integração dos meios de comunicação no ambiente digital / \"The future today: the Radiojournalism education in the age medias\' convergence\" arises from the emergence of a new think about the training process of students university, in the current context, they are prepared to act as journalists in radio stations that have crossed the border of electromagnetic waves and settled also on the Internet, which offer audio content that converge with other media expressivity. This work, which is supported in Communication/Education interface, assumed the purpose of analyzing the occurrence, in the process of training in Radiojournalism, actions that link the theoretical/practical content ministered by medias\' converge. The distancing between the training and the reality came as a hypothesis and the possible lack of activities relating the Radiojournalism and the medias\' convergence. The methodology was based on a literature review, interviews and case studies, that verified training in Radiojournalism in journalism courses offered by leading universities in Brazil and Portugal, which were, respectively: the Departamento de Jornalismo e Editoração da Escola de Comunicações e Artes da Universidade de São Paulo (CJE - ECA/USP) and the Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa (FCSH/UNL). After undertake verification proposed, this study found that the media\'s convergence don\'t appear integrated with theoretical actions / promoted practices by the disciplines in Brazil and Portugal. Meantime it has become evident, in the training processes, the occurrence of technological convergence and content. It was concluded that such a finding allows enlarging in part the students the reality in which the Radio Journalism remains established. On the other hand, the lack of proposals exploiting the medias\' convergence of in the subjects characterized as unfavorable to the formation by don\'t provide to students, knowledge of this phenomenon enhanced by the presence and integration of media in the digital environment.
2

O futuro hoje: a formação em radiojornalismo  na era da convergência das mídias / -

Lourival da Cruz Galvão Júnior 19 March 2015 (has links)
\"O futuro hoje: a formação em Radiojornalismo na era da convergência das mídias\" surge da emergência de um novo pensar sobre o processo de formação dos estudantes universitários que, no atual contexto, são preparados para atuar como jornalistas em emissoras de rádio que ultrapassaram a fronteira das ondas eletromagnéticas e se estabeleceram também na internet, onde disponibilizam conteúdos sonoros que convergem com outras expressividades midiáticas. Este trabalho, que é apoiado na interface Comunicação/Educação, assumiu o propósito de analisar a ocorrência, no processo de formação em Radiojornalismo, de ações que vinculem os conteúdos teórico/práticos ministrados à convergência das mídias. O distanciamento entre a formação e a realidade surgiu como hipótese, bem como a possível falta de atividades relacionando o Radiojornalismo e a Convergência das Mídias. A metodologia baseou-se em pesquisa bibliográfica, entrevistas e estudo de casos que verificou a formação em Radiojornalismo nos cursos de Jornalismo oferecidos pelas principais universidades do Brasil e de Portugal, sendo elas, respectivamente: o Departamento de Jornalismo e Editoração da Escola de Comunicações e Artes da Universidade de São Paulo (CJE - ECA/USP) e a Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa (FCSH/UNL). Após empreender as verificações propostas, este estudo constatou que a convergência das mídias não aparece integrada às ações teórico/práticas promovidas pelas disciplinas, no Brasil e em Portugal. Entretanto ficou evidente, nos processos de formação, a ocorrência das convergências tecnológicas e de conteúdos. Conclui-se que tal constatação permite aproximar, de forma parcial, os alunos da realidade na qual o Radiojornalismo mantém-se estabelecido. De outro lado, a falta de propostas que explorem a convergência das mídias nas disciplinas caracterizou-se como desfavorável à formação por não possibilitar, aos estudantes, conhecimento pleno desse fenômeno potencializado pela presença e integração dos meios de comunicação no ambiente digital / \"The future today: the Radiojournalism education in the age medias\' convergence\" arises from the emergence of a new think about the training process of students university, in the current context, they are prepared to act as journalists in radio stations that have crossed the border of electromagnetic waves and settled also on the Internet, which offer audio content that converge with other media expressivity. This work, which is supported in Communication/Education interface, assumed the purpose of analyzing the occurrence, in the process of training in Radiojournalism, actions that link the theoretical/practical content ministered by medias\' converge. The distancing between the training and the reality came as a hypothesis and the possible lack of activities relating the Radiojournalism and the medias\' convergence. The methodology was based on a literature review, interviews and case studies, that verified training in Radiojournalism in journalism courses offered by leading universities in Brazil and Portugal, which were, respectively: the Departamento de Jornalismo e Editoração da Escola de Comunicações e Artes da Universidade de São Paulo (CJE - ECA/USP) and the Faculdade de Ciências Sociais e Humanas da Universidade Nova de Lisboa (FCSH/UNL). After undertake verification proposed, this study found that the media\'s convergence don\'t appear integrated with theoretical actions / promoted practices by the disciplines in Brazil and Portugal. Meantime it has become evident, in the training processes, the occurrence of technological convergence and content. It was concluded that such a finding allows enlarging in part the students the reality in which the Radio Journalism remains established. On the other hand, the lack of proposals exploiting the medias\' convergence of in the subjects characterized as unfavorable to the formation by don\'t provide to students, knowledge of this phenomenon enhanced by the presence and integration of media in the digital environment.
3

Etude théorique et numérique des équations de Vlasov-Maxwell dans le formalisme covariant.

Back, Aurore 07 November 2011 (has links) (PDF)
Un nouvel point de vue est proposé pour la simulation des plasmas utilisant le modèle cinétique qui couple les équations de Vlasov pour la distribution des particules et les équations de Maxwell pour la contribution des champs électromagnétique. On part du principe que les équations de la Physique sont des objets mathématiques qui mettent en relation des objets géométriques. Afin de conserver les propriètés géométriques des différents objets intervenant dans une équation, on utilise, pour l'étude théorique et numérique, la géométrie différentielle. Il s'avère que toutes les équations de la Physique peuvent s'écrire à l'aide des formes différentielles et que sous ce point de vue celles-ci sont indépendantes du choix des coordonnées. On propose alors une discrétisation des formes différentielles en utilisant les B-splines comme fonctions d'interpolation. Afin d'être cohérent avec la théorie, on proposera également une discrétisation des différentes opérations de la géométrie différentielle agissant sur les formes différentielles. On teste notre schéma tout d'abord sur les équations de Maxwell avec plusieurs conditions aux bords et puisque ce schéma numérique obtenu est indépendant du système de coordonnées, on le teste également lorsque l'on effectue un changement de coordonnées. Enfin, on applique la même méthode sur les équations de Vlasov-Poisson 1D et on propose plusieurs schémas numériques.
4

Investigation of Multiphase Spray Characteristics at High-temperature and High-pressure Conditions using Engine Combustion Network (ECN) standard injectors.

Al-lehaibi, Moaz 12 1900 (has links)
Transportation sector is the backbone of today’s society and its being revolutionized by the development of electric cars. The subject of electrification of the fleet involves many challenges starting from building the require infrastructure all the way to securing raw material for batteries. Charging times and energy density are also two major challenges especially in heavy transportation. With current technologies it is impractical to use electric trucks as the advantages of direct injection engines are unmatched. A typical diesel car or truck has a very long range reaching around 1000 km using single fuel tank. The high energy density of fossil fuels is a corner stone of the heavy transportation sector. It is hard to imagine electric trucks without a breakthrough in battery technology that has very high energy density. High pressure combustion has great potential in extracting more power from liquid fuel. This is mainly attributed to the instant vaporization because of the vanishing surface tension once the fuel goes through a supercritical process, thus energy to vaporize the fuel is saved. Another advantage is in the better mixing that the highly dense and the highly diffused fluid possesses in that region. On the other hand, many of the modelling aspects requires to be investigated. For example, which equation of state predicts the correct density and what are the effect of the pressure and temperature dependant fluid properties on the spray development. To isolate the effect of the high pressure combustion from other possible modelling effects and to facilitate the investigation, simulations using both OpenFOAM and CONVERGE were conducted. First the morphologies of Spray C was numerically characterized under high-temperature and high-pressure conditions. The Volume of fluid method captured the cavitation properly upon using 7.8 μm mesh. The mass flow rate and the transient of the injection process were accurately captured. Implementation of appropriate high pressure models using OpenFOAM to account for real fluid effects showed that three-parameter Redlich-Kwong Peng-Robinson equation of state were superior than two-parameters realfluid equation of state. The correctness of fuel density and viscosity is dependant of the equation of state with ideal gas equation of state being inferior to the realfluid equation of state. The combustion characteristics of Spray A were investigated using coupled Eulerian-Lagrangian approach. This approach demonstrated the ability of the modeling framework in predicting wide variety of parametric effects.
5

Birds of the riparian corridors of Potchefstroom, South Africa / Rindert Wyma

Wyma, Rindert January 2012 (has links)
A riparian ecosystem is the area between the aquatic and terrestrial setting of a stream, and serves as a corridor and habitat for birds. Several riparian ecosystems are located in urban environments, and three main riparian corridors are located in Potchefstroom. They are the Mooi River, Wasgoed Spruit, and Spitskop Spruit, which encompass a wide range of different vegetation types and anthropogenic factors. Therefore, different habitat types for birds occur along the riparian corridors of Potchefstroom. Factors such as food and water availability, nesting sites, competition, predation, learning, presence of other species, and those species that are able to adapt to environmental changes influence the avian diversity and communities along riparian corridors. The hypothesis is that bird variables along the riparian corridors in Potchefstroom are affected by vegetation, anthropogenic, and seasonal influences. To investigate these affects, two secondary objectives were formulated. The first was to characterise riparian avian habitats (CAHs) according to vegetation and anthropogenic factors, and the second was to identify temporal and spatial changes in avian variables. The three streams were divided into 79 consecutive transects, each 300 m long. The study area consisted of: 17 transects along Spitskop Spruit, 12 along Wasgoed Spruit and 50 along the Mooi River. Bird observations were conducted monthly from June 2006 to June 2007. Birds that were observed with a perpendicular distance ≤ 30 meters towards the streams were included in the results. The bird species that were observed were also classified into different nesting and feeding guilds. Environmental data recorded included: vegetation structure (estimated cover percentages and height classes of trees, shrubs, grasses, herbs, sedges, and reeds), anthropogenic structures (estimated cover percentages of roads, footpaths, bridges, electrical pylons, houses, and drainage pipes), and the presence of informal settlers along each transect (the mean number of people and the space they occupy). Vegetation was monitored in summer– (February 2007 until April 2007) and winter months (June 2007 until August 2007). The anthropogenic structures and the presence of informal settlers (anthropogenic factors) were monitored simultaneously with the bird counts. Transect-time profiles were drawn for the four parameters, which differed on spatial and time scales. Multivariate analyses included non-metric multidimensional scaling (NMS), cluster analysis, and indicator species analysis. Cluster analyses and NMS bi-plots were used to define characterised avian habitats (CAHs). Two types of CAHs were characterised: Summer CAHs (summer vegetation and anthropogenic factors) and Anthropogenically CAHs (Anthropogenic factors alone). Bird species were then ordinated with the summer and anthropogenically CAHs on NMS successional vector graphs. The successional vectors illustrate the avian community trajectories of the different CAHs. Indicator species analyses were performed to describe associations between the bird species and the summer and anthropogenically CAHs. The summer and anthropogenic CAHs that were characterised had different avian community trajectories and different species were associated with these CAHs. Different levels in avian diversity appeared among these CAHs, and convergence and divergence in communities appeared among these CAHs. Birds also selected their habitats according to feeding and nesting behaviours. Consequently, it can be deduced that environmental factors such as vegetation structures and anthropogenic factors, as well as seasonality, had an effect on the distribution of birds along the riparian corridors of Potchefstroom. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013
6

Birds of the riparian corridors of Potchefstroom, South Africa / Rindert Wyma

Wyma, Rindert January 2012 (has links)
A riparian ecosystem is the area between the aquatic and terrestrial setting of a stream, and serves as a corridor and habitat for birds. Several riparian ecosystems are located in urban environments, and three main riparian corridors are located in Potchefstroom. They are the Mooi River, Wasgoed Spruit, and Spitskop Spruit, which encompass a wide range of different vegetation types and anthropogenic factors. Therefore, different habitat types for birds occur along the riparian corridors of Potchefstroom. Factors such as food and water availability, nesting sites, competition, predation, learning, presence of other species, and those species that are able to adapt to environmental changes influence the avian diversity and communities along riparian corridors. The hypothesis is that bird variables along the riparian corridors in Potchefstroom are affected by vegetation, anthropogenic, and seasonal influences. To investigate these affects, two secondary objectives were formulated. The first was to characterise riparian avian habitats (CAHs) according to vegetation and anthropogenic factors, and the second was to identify temporal and spatial changes in avian variables. The three streams were divided into 79 consecutive transects, each 300 m long. The study area consisted of: 17 transects along Spitskop Spruit, 12 along Wasgoed Spruit and 50 along the Mooi River. Bird observations were conducted monthly from June 2006 to June 2007. Birds that were observed with a perpendicular distance ≤ 30 meters towards the streams were included in the results. The bird species that were observed were also classified into different nesting and feeding guilds. Environmental data recorded included: vegetation structure (estimated cover percentages and height classes of trees, shrubs, grasses, herbs, sedges, and reeds), anthropogenic structures (estimated cover percentages of roads, footpaths, bridges, electrical pylons, houses, and drainage pipes), and the presence of informal settlers along each transect (the mean number of people and the space they occupy). Vegetation was monitored in summer– (February 2007 until April 2007) and winter months (June 2007 until August 2007). The anthropogenic structures and the presence of informal settlers (anthropogenic factors) were monitored simultaneously with the bird counts. Transect-time profiles were drawn for the four parameters, which differed on spatial and time scales. Multivariate analyses included non-metric multidimensional scaling (NMS), cluster analysis, and indicator species analysis. Cluster analyses and NMS bi-plots were used to define characterised avian habitats (CAHs). Two types of CAHs were characterised: Summer CAHs (summer vegetation and anthropogenic factors) and Anthropogenically CAHs (Anthropogenic factors alone). Bird species were then ordinated with the summer and anthropogenically CAHs on NMS successional vector graphs. The successional vectors illustrate the avian community trajectories of the different CAHs. Indicator species analyses were performed to describe associations between the bird species and the summer and anthropogenically CAHs. The summer and anthropogenic CAHs that were characterised had different avian community trajectories and different species were associated with these CAHs. Different levels in avian diversity appeared among these CAHs, and convergence and divergence in communities appeared among these CAHs. Birds also selected their habitats according to feeding and nesting behaviours. Consequently, it can be deduced that environmental factors such as vegetation structures and anthropogenic factors, as well as seasonality, had an effect on the distribution of birds along the riparian corridors of Potchefstroom. / Thesis (Master of Environmental Sciences)--North-West University, Potchefstroom Campus, 2013
7

The Role of Faith-Based Congregations during Disaster Response and Recovery: A Case Study of Katy, Texas

Elliott, Julie R 12 1900 (has links)
When governments are unable or unwilling to provide necessary relief to communities, local faith-based congregations (FBCs) step in and fill the gap. Though shown to provide for so many needs following disaster, FBCs have largely been left out of the institutional emergency management cycle. The aim of this study was to explore the role of FBCs in the disaster response and recovery process and investigate how recovery impacts FBCs. The primary objective of this study is to gain a better understanding of FBCs and how to better integrate them into the formal emergency management process.The main questions were as follows: First, what is the role of FBCs during the disaster recovery process? Second, how do FBCs change (temporarily and permanently) during disaster recovery, and what factors may promote or inhibit change? To answer these questions, qualitative semistructured interviews were held to develop a case study of Katy, Texas and its recovery from Hurricane Harvey of 2017. The applied and conceptual implications resulting from this study, which apply to FBCs, researchers, emergency managers, and policy makers, highlight the opportunity to better incorporate FBCs formally into emergency management practices.
8

Computational study on the non-reacting flow in Lean Direct Injection gas turbine combustors through Eulerian-Lagrangian Large-Eddy Simulations

Belmar Gil, Mario 21 January 2021 (has links)
[ES] El principal desafío en los motores turbina de gas empleados en aviación reside en aumentar la eficiencia del ciclo termodinámico manteniendo las emisiones contaminantes por debajo de las rigurosas restricciones. Ésto ha conllevado la necesidad de diseñar nuevas estrategias de inyección/combustión que operan en puntos de operación peligrosos por su cercanía al límite inferior de apagado de llama. En este contexto, el concepto Lean Direct Injection (LDI) ha emergido como una tecnología prometedora a la hora de reducir los óxidos de nitrógeno (NOx) emitidos por las plantas propulsoras de los aviones de nueva generación. En este contexto, la presente tesis tiene como objetivos contribuir al conocimiento de los mecanismos físicos que rigen el comportamiento de un quemador LDI y proporcionar herramientas de análisis para una profunda caracterización de las complejas estructuras de flujo de turbulento generadas en el interior de la cámara de combustión. Para ello, se ha desarrollado una metodología numérica basada en CFD capaz de modelar el flujo bifásico no reactivo en el interior de un quemador LDI académico mediante enfoques de turbulencia U-RANS y LES en un marco Euleriano-Lagrangiano. La resolución numérica de este problema multi-escala se aborda mediante la descripción completa del flujo a lo largo de todos los elementos que constituyen la maqueta experimental, incluyendo su paso por el swirler y entrada a la cámara de combustión. Ésto se lleva a cabo través de dos códigos CFD que involucran dos estrategias de mallado diferentes: una basada en algoritmos de generación y refinamiento automático de la malla (AMR) a través de CONVERGE y otra técnica de mallado estático más tradicional mediante OpenFOAM. Por un lado, se ha definido una metodología para obtener una estrategia de mallado óptima mediante el uso del AMR y se han explotado sus beneficios frente a los enfoques tradicionales de malla estática. De esta forma, se ha demostrado que la aplicabilidad de las herramientas de control de malla disponibles en CONVERGE como el refinamiento fijo (fixed embedding) y el AMR son una opción muy interesante para afrontar este tipo de problemas multi-escala. Los resultados destacan una optimización del uso de los recursos computacionales y una mayor precisión en las simulaciones realizadas con la metodología presentada. Por otro lado, el uso de herramientas CFD se ha combinado con la aplicación de técnicas de descomposición modal avanzadas (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificación numérica de los principales modos acústicos en la cámara de combustión ha demostrado el potencial de estas herramientas al permitir caracterizar las estructuras de flujo coherentes generadas como consecuencia de la rotura de los vórtices (VBB) y de los chorros fuertemente torbellinados presentes en el quemador LDI. Además, la implementación de estos procedimientos matemáticos ha permitido tanto recuperar información sobre las características de la dinámica de flujo como proporcionar un enfoque sistemático para identificar los principales mecanismos que sustentan las inestabilidades en la cámara de combustión. Finalmente, la metodología validada ha sido explotada a través de un Diseño de Experimentos (DoE) para cuantificar la influencia de los factores críticos de diseño en el flujo no reactivo. De esta manera, se ha evaluado la contribución individual de algunos parámetros funcionales (el número de palas del swirler, el ángulo de dichas palas, el ancho de la cámara de combustión y la posición axial del orificio del inyector) en los patrones del campo fluido, la distribución del tamaño de gotas del combustible líquido y la aparición de inestabilidades en la cámara de combustión a través de una matriz ortogonal L9 de Taguchi. Este estudio estadístico supone un punto de partida para posteriores estudios de inyección, atomización y combus / [CA] El principal desafiament als motors turbina de gas utilitzats a la aviació resideix en augmentar l'eficiència del cicle termodinàmic mantenint les emissions contaminants per davall de les rigoroses restriccions. Aquest fet comporta la necessitat de dissenyar noves estratègies d'injecció/combustió que radiquen en punts d'operació perillosos per la seva aproximació al límit inferior d'apagat de flama. En aquest context, el concepte Lean Direct Injection (LDI) sorgeix com a eina innovadora a l'hora de reduir els òxids de nitrogen (NOx) emesos per les plantes propulsores dels avions de nova generació. Sota aquest context, aquesta tesis té com a objectius contribuir al coneixement dels mecanismes físics que regeixen el comportament d'un cremador LDI i proporcionar ferramentes d'anàlisi per a una profunda caracterització de les complexes estructures de flux turbulent generades a l'interior de la càmera de combustió. Per tal de dur-ho a terme s'ha desenvolupat una metodología numèrica basada en CFD capaç de modelar el flux bifàsic no reactiu a l'interior d'un cremador LDI acadèmic mitjançant els enfocaments de turbulència U-RANS i LES en un marc Eulerià-Lagrangià. La resolució numèrica d'aquest problema multiescala s'aborda mitjançant la resolució completa del flux al llarg de tots els elements que constitueixen la maqueta experimental, incloent el seu pas pel swirler i l'entrada a la càmera de combustió. Açò es duu a terme a través de dos codis CFD que involucren estratègies de mallat diferents: una basada en la generación automàtica de la malla i en l'algoritme de refinament adaptatiu (AMR) amb CONVERGE i l'altra que es basa en una tècnica de mallat estàtic més tradicional amb OpenFOAM. D'una banda, s'ha definit una metodologia per tal d'obtindre una estrategia de mallat òptima mitjançant l'ús de l'AMR i s'han explotat els seus beneficis front als enfocaments tradicionals de malla estàtica. D'aquesta forma, s'ha demostrat que l'aplicabilitat de les ferramente de control de malla disponibles en CONVERGE com el refinament fixe (fixed embedding) i l'AMR són una opció molt interessant per tal d'afrontar aquest tipus de problemes multiescala. Els resultats destaquen una optimització de l'ús dels recursos computacionals i una major precisió en les simulacions realitzades amb la metodologia presentada. D'altra banda, l'ús d'eines CFD s'ha combinat amb l'aplicació de tècniques de descomposició modal avançades (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificació numèrica dels principals modes acústics a la càmera de combustió ha demostrat el potencial d'aquestes ferramentes al permetre caracteritzar les estructures de flux coherents generades com a conseqüència del trencament dels vòrtex (VBB) i dels raigs fortament arremolinats presents al cremador LDI. A més, la implantació d'estos procediments matemàtics ha permès recuperar informació sobre les característiques de la dinàmica del flux i proporcionar un enfocament sistemàtic per tal d'identificar els principals mecanismes que sustenten les inestabilitats a la càmera de combustió. Finalment, la metodologia validada ha sigut explotada a traves d'un Diseny d'Experiments (DoE) per tal de quantificar la influència dels factors crítics de disseny en el flux no reactiu. D'aquesta manera, s'ha avaluat la contribución individual d'alguns paràmetres funcionals (el nombre de pales del swirler, l'angle de les pales, l'amplada de la càmera de combustió i la posició axial de l'orifici de l'injector) en els patrons del camp fluid, la distribució de la mida de gotes del combustible líquid i l'aparició d'inestabilitats en la càmera de combustió mitjançant una matriu ortogonal L9 de Taguchi. Aquest estudi estadístic és un bon punt de partida per a futurs estudis de injecció, atomització i combustió en cremadors LDI. / [EN] Aeronautical gas turbine engines present the main challenge of increasing the efficiency of the cycle while keeping the pollutant emissions below stringent restrictions. This has led to the design of new injection-combustion strategies working on more risky and problematic operating points such as those close to the lean extinction limit. In this context, the Lean Direct Injection (LDI) concept has emerged as a promising technology to reduce oxides of nitrogen (NOx) for next-generation aircraft power plants In this context, this thesis aims at contributing to the knowledge of the governing physical mechanisms within an LDI burner and to provide analysis tools for a deep characterisation of such complex flows. In order to do so, a numerical CFD methodology capable of reliably modelling the 2-phase nonreacting flow in an academic LDI burner has been developed in an Eulerian-Lagrangian framework, using the U-RANS and LES turbulence approaches. The LDI combustor taken as a reference to carry out the investigation is the laboratory-scale swirled-stabilised CORIA Spray Burner. The multi-scale problem is addressed by solving the complete inlet flow path through the swirl vanes and the combustor through two different CFD codes involving two different meshing strategies: an automatic mesh generation with adaptive mesh refinement (AMR) algorithm through CONVERGE and a more traditional static meshing technique in OpenFOAM. On the one hand, a methodology to obtain an optimal mesh strategy using AMR has been defined, and its benefits against traditional fixed mesh approaches have been exploited. In this way, the applicability of grid control tools available in CONVERGE such as fixed embedding and AMR has been demonstrated to be an interesting option to face this type of multi-scale problem. The results highlight an optimisation of the use of the computational resources and better accuracy in the simulations carried out with the presented methodology. On the other hand, the use of CFD tools has been combined with the application of systematic advanced modal decomposition techniques (i.e., Proper Orthogonal Decomposition and Dynamic Mode Decomposition). The numerical identification of the main acoustic modes in the chamber have proved their potential when studying the characteristics of the most powerful coherent flow structures of strongly swirled jets in a LDI burner undergoing vortex breakdown (VBB). Besides, the implementation of these mathematical procedures has allowed both retrieving information about the flow dynamics features and providing a systematic approach to identify the main mechanisms that sustain instabilities in the combustor. Last, this analysis has also allowed identifying some key features of swirl spray systems such as the complex pulsating, intermittent and cyclical spatial patterns related to the Precessing Vortex Core (PVC). Finally, the validated methodology is exploited through a Design of Experiments (DoE) to quantify the influence of critical design factors on the non-reacting flow. In this way, the individual contribution of some functional parameters (namely the number of swirler vanes, the swirler vane angle, the combustion chamber width and the axial position of the nozzle tip) into both the flow field pattern, the spray size distribution and the occurrence of instabilities in the combustion chamber are evaluated throughout a Taguchi's orthogonal array L9. Such a statistical study has supposed a good starting point for subsequent studies of injection, atomisation and combustion on LDI burners. / Belmar Gil, M. (2020). Computational study on the non-reacting flow in Lean Direct Injection gas turbine combustors through Eulerian-Lagrangian Large-Eddy Simulations [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159882

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