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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.
81

[en] EXPERIMENTAL EVALUATION OF DEPOSITS IN FUEL INJECTORS OF A GASOLINE DIRECT INJECTION ENGINE / [pt] AVALIAÇÃO EXPERIMENTAL DE DEPÓSITOS EM BICOS DE UM MOTOR COM INJEÇÃO DIRETA DE GASOLINA

LEONARDO COSTA BRAGA 03 May 2019 (has links)
[pt] O desenvolvimento de um motor de quatro tempos, de ignição por centelha, com injeção direta de combustível dentro da câmara de combustão foi uma iniciativa importante para o mercado automobilístico mundial. O potencial termodinâmico deste tipo de motor e sua notória melhoria na economia de combustível têm feito com que a tecnologia seja foco de um grande número de projetos de pesquisa, com o objetivo de entender, desenvolver e aperfeiçoar o sistema de injeção direta de combustível. No entanto, para atender aos novos limites de emissões estabelecidas pela especificação EURO 5, foi necessária uma reavaliação do projeto da geometria do injetor, o que ocasionou no desenvolvimento de um novo componente com um maior número de furos e com uma redução do diâmetro dos mesmos (injetor multifuros). Essa alteração no projeto visa garantir uma melhor pulverização, otimização da relação ar/combustível e, consequentemente, um melhor processo de queima na câmara de combustão, atendendo dessa forma os limites de emissões estabelecidos pela diretriz normativa vigente. Os processos de preparação da mistura, injeção, vaporização e controle do escoamento de ar dentro do cilindro têm sido as principais fontes de publicações de periódicos que estudam o sistema de injeção direta. O presente trabalho, por sua vez, tem por finalidade avaliar a formação de depósitos de compostos inorgânicos nos injetores, provenientes da utilização de combustíveis formulados com diferentes teores de sulfato. O motor utilizado para execução dos testes foi o EP6CDT da PSA Peugeot Citroen. No estudo foram realizados ensaios em bancada de testes e em veículos (estrada e dinamômetro). Outros veículos com a mesma tecnologia, disponíveis no mercado brasileiro, também foram testados. As variáveis avaliadas durante o projeto foram: a composição química de diferentes combustíveis, fator de correção do tempo de injeção (FRA) e a vazão através dos bicos injetores no decorrer dos testes. Os estudos indicaram que a mudança na geometria dos injetores, somada a composição das gasolinas nacionais testadas, originou a formação dos depósitos que será discutida ao longo deste trabalho. / [en] The development of a four-stroke engine, spark ignition, with direct injection of fuel into the combustion chamber was an important initiative for the global automotive market. The thermodynamic potential of this type of engine and its significant improvement in fuel economy have meant this technology as focus of a large number of research projects, with the objective to understand, develop and improve the system of direct fuel injection. However, to meet new emission limits set by Euro 5 specification, it was necessary to reevaluate the geometry design of the injector, which resulted in the development of a new component with a larger number of holes and with a diameter reduction (multi-holes injector). This change in the project aims to ensure a better spray, optimizing air / fuel ratio and, consequently, a better process of combustion inside the combustion chamber, satisfying the emission limits established by the applicable norms. The processes for preparing the mixture, injection, atomization and air flow control inside the cylinder have been the main source of periodic publications that study the direct injection system. Therefore, this paper purpose is to evaluate the formation of inorganic deposits in the injectors using fuels formulated with different amounts of sulfate. The engine used for running the tests was the EP6CDT of PSA Peugeot Citroen. For this study one has performed tests on test bench and in vehicles (road and dynamometer). Other vehicles, with the same technology available in Brazil, were also tested. The variables evaluated during the project were: the chemical composition of different fuels, the correction factor from the injection time (FRA) and flow through the injectors during the tests. This study has indicated that the injector geometry modification, coupled with tested compositions of gasoline, resulted in the formation of deposits that will be discussed throughout this work.
82

Injection de spin dans les semiconducteurs et les matériaux organiques / Spin injection into semiconductors and organic materials

Gao, Xue 20 June 2019 (has links)
La spintronique utilisant des matériaux semi-conducteurs est un sujet de recherche très actif. Elle permet de combiner le potentiel des semi-conducteurs avec le potentiel des matériaux magnétiques. Le GaN pourrait être un bon candidat pour des applications en spintronique car le temps de relaxation de spin est très long. La spintronique organique est également un domaine de recherche en plein essor en raison de la longue durée de vie de spin des porteurs de charge ainsi que de leur coût relativement bas, de leur flexibilité et de leur diversité chimique. Dans un premier temps, nous montrerons que la polarisation circulaire de la lumière émise par une LED contenant une couche unique de points quantiques InAs / GaAs (QD) InAs / GaAs dopés p peut atteindre environ 18% sans champ magnétique extérieur. Une corrélation claire est établie entre le degré de polarisation de la lumière émise et l’aimantation perpendiculaire de l’injecteur. La polarisation atteint un maximum pour une polarisation appliquée de 2.5 V à 10 K, ce qui correspond à un courant injecté de 6 µA. En outre, nous observons un comportement remarquable de la polarisation pour un température comprise entre 60K et 80K. L’évolution de la polarisation en fonction de la température est discutée à la lumière de la compétition entre le temps de vie de recombinaison radiative τr et le temps de relaxation de spin τs. De plus, nous avons développé un injecteur de spin présentant une anisotropie magnétique perpendiculaire sur GaN. Nous avons d’abord optimisé la croissance de MgO pour différentes températures du substrat. Nous avons ensuite étudié la croissance de Fe puis de Co sur MgO/GaN. L’injecteur de spin Co(0001)/MgO(111) a été retenu car celui-ci permet d’obtenir un anisotropie magnétique perpendiculaire. De plus, les calculs ab initio ont également montré que l’interface Co/MgO(111) présente une grande anisotropie magnétique. Finalement, nous étudions les MFTJ basés sur une barrière de PVDF organique dopée avec des nano-particules de Fe3O4. Nous avons fabriqué avec succès une multicouche de La0.6Sr0.4MnO3/PVDF:Fe3O4/Co, dans laquelle la barrière organique en poly (fluorure de vinylidène) (PVDF) a été dopée avec des nanoparticules ferromagnétiques de Fe3O4. En modifiant la polarisation du PVDF, l’effet tunnel dans la jonction multiferroïque peut être commuté via la partie LSMO/PVDF/Co (polarisation positive) ou via la partie Fe3O4/PVDF/Co (polarisation négative). Cela correspond à une inversion de la magnétorésistance à effet tunnel (TMR) de + 10% à -50%, respectivement. Notre étude montre que les jonctions tunnel multiferroïques organiques dopées avec des particules magnétiques pourraient créer de nouvelles fonctionnalités en jouant sur l’interaction du magnétisme des nanoparticules avec la ferroélectricité de la barrière organique. / Spintronics with semiconductors is very attractive as it can combine the potential of semiconductors with the potential of the magnetic materials. GaN has a long spin relaxation time, which could be of potential interest for spintronics applications. Organic spintronics is also very appealing because of the long spin lifetime of charge carriers in addition to their relatively low cost, flexibility, and chemical diversity. In this thesis, we investigate spin injection in spin LEDs containing either InAs/GaAs quantum dots or InGaN/GaN quantum wells. Moreover, we further study spin polarized transport in organic multiferroic tunnel junctions (OMFTJs). Firstly, we will show that the circular polarization of the light emitted by a LED containing a single layer of p-doped InAs/GaAs quantum dots (QDs) can reach about 18% under zero applied magnetic field. A clear correlation is established between the polarization degree of the emitted light and the perpendicular magnetization of the injector layer. The polarization reaches a maximum for an applied bias of 2.5V at 10K, which corresponds to an injected current of 6 µA. Also, we report a remarkable behavior of the polarization in the temperature region 60-80K. The interpretation of the bias and temperature dependence of the polarization is discussed in light of the competition between radiative recombination time τr and the spin relaxation time τs. In addition, significant efforts have been devoted to developing a perpendicular spin injector on GaN based materials to achieve spin injection without applying a magnetic field. Firstly, the growth of MgO has been investigated at various growth temperatures. Then, we studied the growth of either Fe or Co on MgO/GaN. In contrast to Fe/MgO, the Co/MgO spin injector yields a clear perpendicular magnetic anisotropy. In addition, ab-initio calculations have been performed to understand the origin of the perpendicular magnetic anisotropy at the Co/MgO(111) interface. Finally, we investigate multiferroic tunnel junctions (MFTJs) based on organic PVDF barriers doped with Fe3O4 nano particles. The organic MFTJs have recently attracted much attention since they can combine advantages of spintronics, organic and ferroelectric electronics. We report on the successful fabrication of La0.6Sr0.4MnO3/PVDF:Fe3O4/Co OMFTJ, where the poly(vinylidene fluoride) (PVDF) organic barrier has been doped with ferromagnetic Fe3O4 nanoparticles. By changing the polarization of the ferroelectric PVDF, the tunneling process in OMFTJ can be switched either through the LSMO/PVDF/Co part (positive polarization) or through the Fe3O4/PVDF/Co part (negative polarization). This corresponds to a reversal of tunneling magnetoresistance (TMR) from +10% to -50%, respectively. Our study shows that the doping of OMFTJs with magnetic nanoparticles can create new functionalities of organic spintronic devices by the interplay of nanoparticle magnetism with the ferroelectricity of the organic barrier.
83

A Study of the Characteristics of Gas-On-Liquid Impinging Injectors

Rakesh, P January 2014 (has links) (PDF)
The work presented here pertains to investigations on gas-on-liquid type of impinging injectors with a generic approach with prospective applications in several areas, and at places with particular emphasis on cryogenic or semi-cryogenic liquid propellant rockets. In such rockets, one of the components arrives at the injector in a gaseous phase after passing through the regenerative coolant passages or a preceding combustion stage. Most often, the injectors in such systems are of shear coaxial type. The shear coaxial injectors suffer from several disadvantages like complexity in design, manufacture and quality control. Adoption of impinging jet configuration can alleviate these problems in addition to providing further benefits in terms of cost, robustness in high temperature environment and manifolding. However, there is very little literature on gas-on-liquid injectors either in this context or in any other Even for the simplest form of impinging injectors such as like-on-like doublets, literature provides no conclusive direction at describing a spray from the theoretical models of physical mechanisms. Empirical approach is still the prime mode of obtaining a proper understanding of the phenomena. Steady state spray characterization includes mainly of describing the spatial distribution of liquid mass and drop size distribution as a function of geometric and injection parameters. The parameters that are likely to have an impact on spray characteristics are orifice diameter, ratio of orifice length to diameter, pre-impingement length of individual jets, inter orifice distance, impingement angle, jet velocity and condition of the jet just before impingement. The gas-on- liquid configuration is likely to experience some qualitative changes because of the expansion of the gas jet. The degree to which each one of the above variables influences the drop size and mass distribution having implication to combustion performance forms the core theme of the thesis. A dedicated experimental facility has been built, calibrated and deployed exhaustively. While spray drop size measurement is done largely by a laser diffraction instrument, some of the cases warranted an image processing technique. Two different image processing algorithms are developed in-house for this purpose. The granulometric image processing method developed earlier in the group for cryogenic sprays is modified and its applicability to gas-on-liquid impinging sprays are verified. Another technique based on the Hough transform which is feature extraction technique for extracting quantitative information has also been developed and used for gas-on-liquid impinging injectors. A comparative study of conventional liquid-on-liquid doublet with gas-on-liquid impinging injectors are first made to establish the importance of studying gas-on-liquid impinging injectors. The study identifies the similarities and differences between the two types and highlights the features that make such injectors attractive as replacements to coaxial configuration. Spray structure, drop-size mass distributions are quantified for the purpose of comparison. This is followed by a parametric study of the gas-on-liquid impinging injectors carried out using identified control variables. Though momentum ratio appeared to be a suitable parameter to describe the spray at any given impingement angle, the variations due to impingement angle had to be factored in. It was found that normal gas momentum to liquid mass is an apt parameter to generalize the spray characteristics. It was also found that using identical nozzles for desired mass ratio could lead to rather large deflection of the spray which may not be acceptable in combustion chamber design. One way of overcoming this is to work with unequal orifice sizes for gas and liquid. It was found that using smaller gas orifice for a given liquid orifice resulted in lower SMD (Sauter Mean Diameter of the spray) for constant gas and liquid mass flow rates. This is attributable to the high dynamic pressure of gas in the case of smaller gas orifices for the same mass flow rate. The impinging liquid jets with unequal momentum in the doublet configuration would result in non-uniform mass and mixture ratio distribution within the combustion chamber which may have to operate under varying conditions of mass flow rates and/or mixture ratio. The symmetrical arrangement of triplet configuration can eliminate this problem at the same time generating finely atomized spray and a homogeneous mixture ratio. In view of the scanty literature available in this field, the atomization characteristics of the spray generated by liquid centered triplet jets are examined in detail. It was found that as in the case of gas-on-liquid impinging doublets, normal gas momentum to liquid mass is an ideal parameter in describing the spray. Variants of this configuration are studied recently for many other applications too. As done in the case of doublets, efforts have also been made to compare gas centered triplet to liquid-liquid triplet. It was found that the trend of SMD of gas centered triplet is different from that of liquid-liquid triplets, thus pointing to a different mechanism in play. The SMD in the case of liquid-liquid triplets decreases monotonically with increasing specific normal momentum. It is to be noted that specific normal momentum is an ideal parameter for describing the spray characteristics of liquid-liquid triplets and doublets. In the case of gas centered triplet the SMD first increases and then decreases with specific normal momentum, the inversion point depends on the gas mass flow rate for a constant specific normal momentum. The thesis concludes with a summary of the major observations of spray structures for all the above injector configurations and quantifies the parametric dependencies that would be of use to engineering design
84

RANS and LES of multi-hole sprays for the mixture formation in piston engines

Khan, Muhammad 20 January 2014 (has links)
Cette thèse porte sur la simulation des jets de gouttes générés par des pulvérisateurs essence haute pression, pulvérisateurs qui sont un point clef des systèmes de combustion automobile de la présente et future génération devant diminuer les émissions de CO2 et de polluants. Dans un premier temps les jets de gouttes (« sprays ») sont simulés par simulation moyennée. Les résultats de simulation d’un jet donnant des résultats en moyenne satisfaisant, l'interaction de jets en injecteurs multi-trous est alors simulée. Les résultats sont cohérents par rapport aux mesures d'entraînement d’air. La simulation permettant d'avoir accès au champ complet 3D, le mécanisme d'interaction jet à jet et de développement instationnaire du spray est décrit en détail. La formation d’un mouvement descendant au centre du spray et celle d'un point d'arrêt central sont trouvés. Finalement, Ces résultats sont étendus au cas surchauffé, cas où la pression dans la chambre est inférieure à la pression de vapeur saturante. Un modèle simple semi-empirique est proposé pour tenir compte de la modification des conditions proches de la buse d’injection. Le modèle prédit correctement les tendances des variations de paramètres et capture la forme générale du spray qui se referme sur lui-même. La seconde grande partie est consacrée au développement d’un modèle de spray par l’approche des grandes échelles (SGE), limité ici aux cas non évaporant. Il comprend la modélisation de sous-maille de la dispersion turbulente, des collisions-coalescence et des termes d’échange de quantité de mouvement de sous-maille. L'effet du choix du modèle de sous-maille pour la viscosité turbulente de sous-maille est montré, le choix retenu étant le modèle de Smagorinski dynamique. Afin d'améliorer la représentativité cruciale des conditions d’injections, un couplage faible est réalisé à partir de résultats de simulations existantes de l'écoulement interne aux buses. Les fonctions densité de probabilité simple et jointes extraits des résultats de simulations sont validés par rapport aux mesures PDA en situation pseudo-stationnaire et la pénétration liquide et la forme du spray est comparée aux visualisations par ombroscopie. Enfin, différentes zones caractéristiques sont identifiées et des longueurs sont notées pour les cas d'injection à 100 et 200bar. / Over the years numerical modelling and simulation techniques have constantly been improved with the increase in their use. While keeping the computational resources in mind, numerical simulations are usually adapted to the required degree of accuracy and quality of results. The conventional Reynolds Average Navier Stokes (RANS) is a robust, cheap but less accurate approach. Large Eddy Simulation (LES) provides very detailed and accurate results to the some of the most complex turbulence cases but at higher computational cost. On the other hand, Direct Numerical Simulation (DNS) is although the most accurate of the three approaches but at the same time it is computationally very expensive which makes it very difficult to be applied to the most of the complex industrial problems. The current work is aimed to develop a deeper understanding of multi-hole Gasoline Direct Injection (GDI) sprays which pose many complexities such as; air entrainment in the multi-hole spray cone, Jet-to-Jet interactions, and changes in the spray dynamics due to the internal flow of the injector. RANS approach is used to study multi-hole injector under cold, hot and superheated conditions. Whereas, LES is utilized to investigate the changes in the dynamics of the single spray plume due to the internal flow of the GDI injector. To reduce computational cost of the simulations, dynamic mesh refinement has been incorporated for both LES and RANS simulation. A thorough investigation of air entrainment in three and six hole GDI injectors has been carried out using RANS approach under non superheated and superheated conditions. The inter plume interactions caused by the air entrainment effects have been analysed and compared to the experimental results. Moreover, the tendencies of semi collapse and full collapse of multi-hole sprays under non superheated and superheated conditions have been investigated in detail as well. A methodology of LES has been established using different injection strategies along with various subgrid scale models for a single spray plume. In GDI multi-hole sprays, the internal flow of the injector plays a very crucial role in the outcome the spray plume. A separate already available internal flow LES simulation of the injector has been coupled with the external spray simulation in order to include the effect of nozzle geometry and the cavitation phenomenon which completely change the dynamics of the spray.
85

Modeling of liquid film and breakup phenomena in Large-Eddy Simulations of aeroengines fueled by airblast atomizers / Modélisation des phénomènes de film liquide et d'atomisation pour la simulation aux grandes échelles de turbines a gaz alimentées par atomiseurs airbla

Chaussonnet, Geoffroy 13 May 2014 (has links)
Les turbines à gaz doivent satisfaire des normes d'émission polluantes toujours en baisse. La formation de polluants est directement liée à la qualité du mélange d'air et de carburant en amont du front de flamme. Ainsi, leur réduction implique une meilleure prédiction de la formation du spray et de son interaction avec l'écoulement gazeux. La Simulation aux Grandes Échelles (SGE) semble un outil numérique approprié pour étudier ces mécanismes. Le but de cette thèse est de développer des modèles phénoménologiques décrivant la phase liquide notamment le film et son atomisation en bout de lèvre d'injecteur, dans un contexte SGE. Ces modèles sont validés ou calibrés sur l'expérience académique réalisée par l'Institut für Thermische Strömungsmaschinen (ITS) de l'université technologique de Karlsruhe (KIT), et appliqués dans une configuration réelle de moteur d'hélicoptère. Dans un premier temps, le film liquide mince est décrit par une approche Lagrangienne. Les particules de film représentent un volume élémentaire de liquide adhérent à la paroi. L'équation du mouvement est donnée par l'intégration des équations de Saint-Venant sur l'épaisseur du film. La dynamique du film est donnée par le gradient de pression longitudinal, le cisaillement interfacial du gaz et la gravité. Dans un second temps, l'atomisation du film est caractérisée par la distribution de taille de gouttes du spray généré. Celle-ci est décrite par une distribution de Rosin-Rammler dont les coefficients sont paramétrés par la vitesse du gaz, la tension superficielle du liquide et l'épaisseur de la lèvre de l'injecteur. Les constantes de ce modèle, baptisé PAMELA, sont calibrées sur l'expérience du KIT-ITS. La simulation de l'expérience KIT-ITS permet de valider le modèle de film, de vérifier la robustesse du modèle PAMELA, et de comparer qualitativement l'angle du spray généré. L'application de ces modèles dans une configuration réelle partiellement instrumentée permet de valider PAMELA sans modification de ses constantes, et d'étudier leur impact sur la structure de flamme, comparé aux méthodes traditionnelles d'injection liquide. / Aeronautical gas turbines need to satisfy growingly stringent demands on pollutant emission. Pollutant emissions are directly related to the quality of fuel air mixing prior to combustion. Therefore, their reduction relies on a more accurate prediction of spray formation and interaction of the spray with the gaseous turbulent flow field. Large-Eddy Simulation (LES) seems an adequate numerical tool to predict these mechanisms. The objectives of this thesis is to develop phenomenological models describing the liquid phase, in particular the film and its atomization at the injector atomizing lips, in the context of LES. These models are validated or calibrated on the academic experiment performed at Institut für Thermische Strömungsmaschinen (ITS) from the Karlsruhe Institute of Technology (KIT), and applied to a helicopter engine real configuration. In a first step, the thin liquid film is described by a Lagangian approach. Film particles represent an elementary volume of liquid at the wall surface. The equation of motion is given by integrating the Saint-Venant equations over the film thickness. The film dynamics derives from the pressure gradient, the interfacial shear and gravity. In a second step, the film breakup is characterized by the drop size distribution of the spray. The former one is described by a Rosin-Rammler distribution, whose coefficients depend on the gas velocity, the liquid surface tension and the atomizing edge thickness of the injector. The model, labelled PAMELA, is calibrated from the KIT-ITS experiment. The simulation of the KIT-ITS experiment allows to validate the film model, to check PAMELA robustness, and to compare qualitatively the spray angle. The application of these models in a real configuration allows to check PAMELA robustness without constants modification, and to study their impact on the flame structure, in comparison with usual methods of liquid injection.
86

Aplikace vstřikovacího systému s tlakovým zásobníkem na vznětový šestiválcový motor / Application of Pressure Accumulator Injection System on Six-cylinder CI Engine

Pacovský, Tomáš January 2011 (has links)
This master's thesis deals with application of modern injection system Common Rail on six-cylinder CI engine. One of aims of thesis is to get a large overview of pressure accumulator injection system and explore the development in this area. Among main aims of the thesis belong a new construction layout in Pro/Engineer, accomplishing of static and dynamic analyse of most important parts via the finite element method (FME) and necessary control calculations. Finally, the design documentation of new most essential designed parts will be made. During making the thesis necessary source materials obtained from Vývojový ústav traktorů a.s. of Zetor Group company was made use of.
87

Návrh a realizace managovatelného PoE injektoru / Design and implementation of managed PoE injector

Frkal, Pavel January 2016 (has links)
This study deals with power supply for network devices using existing structured cabling. Various power supplies are analysed including their limitations and also deals with measuring of the consumed energy. The outcome is 24-port passive PoE injector for remote power supply of network equipment. It's suitable namely for remote devices which lacks built-in PoE support as these do not need major modifications (using passive injection). Power options including current measurement may be done via administrative web interface.
88

Analyse expérimentale par diagnostics lasers du mélange kérosène/air et de la combustion swirlée pauvre prémélangée, haute-pression issue d’un injecteur Low-NOx / Experimental investigation by laser diagnostics of the kerosene/air mixing and high-pressure swirl-stabilized lean premixed combustion from a low-NOx injection system

Malbois, Pierre 18 December 2017 (has links)
Les motoristes aéronautiques misent sur le développement de systèmes d’injection de carburant innovants pour réduire la consommation de carburant et les émissions de polluants. L’objectif de la thèse est de contribuer à l’étude expérimentale d’un injecteur « Lean Premixed » par le développement de diagnostics lasers couplant des approches basées sur la diffusion de Mie et l’émission fluorescente de traceurs. Les mesures ont été réalisées sur le banc de combustion haute pression HERON. Une approche novatrice avec l’imagerie de fluorescence du kérosène a permis d’obtenir une quantification du mélange kérosène/air. La structure de flamme a été mesurée simultanément par PLIF-OH et des mesures PIV de vitesse ont complété cette analyse. Un développement préliminaire de la PLIF-CO a également été mené. Les nombreuses mesures permettent de fournir une analyse détaillée des interactions flamme/spray/aérodynamique lors d’une combustion swirlée stabilisée kérosène/air à haute pression. / Aeronautical engine manufacturers are banking on the development of innovative fuel injection systems to reduce fuel consumption and pollutant emissions. The aim of the thesis is to contribute to the experimental investigation of a "Lean Premixed" injector by developing laser diagnostics coupling approaches based on Mie scattering and fluorescent emission of tracers. Measurements are performed at high pressure on the HERON combustion test bench. An innovative approach with fluorescence imaging of kerosene has resulted in the quantification of the kerosene/air mixture. The flame structure was analyzed simultaneously by OH-PLIF and velocity PIV measurements were performed to complete this analysis. A preliminary development of CO-PLIF was also conducted. The numerous measurements provided a detailed analysis of the mechanisms of flame/spray/aerodynamic interactions during a swirl-stabilized kerosene/air combustion at high pressure.
89

Injector Waveform Monitoring of a Diesel Engine in Real-Time on a Hardware in the Loop Bench

Farooqi, Quazi Mohammed Rushaed 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis presents the development, experimentation and validation of a reliable and robust system to monitor the injector pulse generated by an Engine Control Module (ECM) and send the corresponding fueling quantity to the real-time computer in a closed loop Hardware In the Loop (HIL) bench. The system can be easily calibrated for different engine platforms as well. The fueling quantity that is being injected by the injectors is a crucial variable to run closed loop HIL simulation to carry out the performance testing of engine, aftertreatment and other components of the vehicle. This research utilized Field Programmable Gate Arrays (FPGA) and Direct Memory Access (DMA) transfer capability offered by National Instruments (NI) Compact Reconfigurable Input-Output (cRIO) to achieve high speed data acquisition and delivery. The research was conducted in three stages. The first stage was to develop the HIL bench for the research. The second stage was to determine the performance of the system with different threshold methods and different sampling speeds necessary to satisfy the required accuracy of the fueling quantity being monitored. The third stage was to study the error and its variability involved in the injected fueling quantity from pulse to pulse, from injector to injector, between real injector stators and cheaper inductor load cells emulating the injectors, over different operating conditions with full factorial design of experimentation and mixed model Analysis Of Variance (ANOVA). Different thresholds were experimented to find out the best thresholds, the Start of Injection (SOI) threshold and the End of Injection (EOI) threshold that captured the injector “ontime” with best reliability and accuracy. Experimentation has been carried out at various data acquisition rates to find out the optimum speed of data sampling rate, trading off the accuracy of fueling quantity. The experimentation found out the expected error with a system with cheaper solution as well, so that, if a test application is not sensitive to error in fueling quantity, a cheaper solution with lower sampling rate and inductors as load cells can be used. The statistical analysis was carried out at highest available sampling rate on both injectors and inductors with the best threshold method found in previous studies. The result clearly shows the factors that affect the error and the variability in the standard deviations in error; it also shows the relation with the fixed and random factors. The real-time application developed for the HIL bench is capable of monitoring the injector waveform, using any fueling ontime table corresponding to the platform being tested, and delivering the fueling quantity in real-time. The test bench made for this research is also capable of studying injectors of different types with the automated test sequence, without occupying the resource of fully capable closed loop test benches for testing the ECM unctionality.
90

Development of a compact test facility for SRF Photoelectron injectors

Völker, Jens 09 August 2018 (has links)
SHF Photoelektroneninjektoren sind eine vielversprechende Elektronquelle für hochbrillante Teichenbeschleuniger mit hohem mittlerem Strom und kurzen Teilchenpulsen, wie FELs und ERLs. Für das ERL Projekt bERLinPro wurde einer unabhängige Testanlage GunLab entwickelt um die Leistungsfähigkeit der Injektoren und die Strahlparameter zu überprüfen. Darüber hinaus können neue Komponenten zur Strahldiagnose getestet werden. Die Hauptaufgabe von GunLab ist die Beschreibung des vollständigen sechsdimensionalen Phasenraums der Elektronen in Abhängigkeit aller Injektorparameter. Die Anlage besteht aus einer kompakten Diagnosestrahlführungan dem SHF Photoelektroneninjektoren und einem Kathodenlasersystem. Im Rahmen dieser Arbeit wurden analytische und numerische Studien zu den SHF Photoelektroneninjektoren durchgeführt, um zu erwartende Strahlparameter zu detektieren und die Anforderungen an die Strahldiagnose festzulegen. Darüber hinaus wurden verschiedene Emittanzbeiträge der einzelnen Injektorkomponenten untersucht. Diesbezüglich wurde das Magnetfeld des aktuellen Solenoiden kartiert und auf Asymmetrien getestet, die ebenfalls zu Emittanzvergrößerungen beitragen können. Eine der wesentlichen Komponenten der Diagnosestrahlführung ist das (transversale) Phasenraummesssystem, für das eine besondere Magnetgeometrie entwickelt wurde. Weitere Diagnose Komponenten sind ein optimierter Spektrometerdipol und eine transversal ablenkende Kavität, durch die sich zusammen mit zwei Quadrupolmagneten die Scheibenemittanz bestimmen lässt. Für GunLab wurden unterschiedliche optische Messsysteme entwickelt und optimiert. Der herausforderndste Aufbau ist dabei das Strahl-Halo Messsystem. Es ermöglicht die Beobachtung der transversalen Ladungsverteilung über einen Dynamikbereich von bis zu 6 Größenordnungen. Die Leistungsfähigkeit und die Auflösung aller Messsysteme und Messroutinen wurden bestimmt, um die Visualisierung des kompletten Phasenraums durch GunLab sicher zu stellen. / SRF photoelectron injectors are promising electron sources for high brightness accelerators with high average current and short pulse duration like FELs and ERLs. For the ERL project bERLinPro an independent test facility called GunLab was developed and set up to optimize the operation performance of SRF photoinjectors and the electron beam parameters. Furthermore, GunLab allows to investigate the operation of different kinds of photocathodes in the environment of an SRF accelerator and to study new beam diagnostic concepts. Of outmost importance is the characterization of the full six dimensional phase space as a function of all injector parameters. GunLab consists of the compact diagnostic beam line, connected to the SRF photoinjetor module, and a drive laser. In the context of this thesis, analytical and numerical investigations of the SRF photoinjector were performed to estimate beam parameter ranges and to determine the diagnostics requirements. Furthermore, various emittance contributors of the injector were determined. Thereby the magnetic field of the final designed solenoid was measured to determine field asymmetries, which are one major source of emittance growth. One of the central diagnostic components of the beamline is the (horizontal) phase space scanner system. For this purpose, a dedicated air-coil magnet design was developed. Additional diagnostic components include an optimized spectrometer system, a transverse deflecting cavity (TCav) and two quadrupole magnets, to determine longitudinal and sliced emittance. For GunLab different optical measurement systems were developed and optimized, the most challenging setup is a beam halo measurement system. This device is able to observe the transverse charge density with a dynamic range of up to 6 orders of magnitude. The performance and the resolution of all measurement systems and routines for GunLab were determined to ensure the visualization of the electron beam phase space.

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