The ion acceleration process in Bipolar High Power Impulse Magnetron Sputteringis investigated for use in a novel space propulsion system - the BP-HiPIMS thruster.The interest for BP-HiPIMS has recently been growing within the area of thin filmdeposition due to the theorised acceleration of target ions caused by the reversedpulse following the regular HiPIMS pulse. This same acceleration could be usedto produce thrust in a space propulsion system, where the lack of physical gridsand temporal separation of ionisation and acceleration are attractive benefits of thesuggested system. In this paper the physical processes and parameters of importanceare experimentally investigated to gain understanding of the ion acceleration processwith the goal of verifying the theory of BP-HiPIMS thusters.Through plasma potential measurements a beneficial potential structure between themagnetic trap and bulk of the plasma which could potentially accelerate ions is foundat certain discharge conditions and some acceleration of ions is confirmed in massspectrometer measurements. The results are promising for a thruster application butfurther research is needed to evaluate the viability of the proposed system. / Jonaccelerationsprocessen i Bipolar High Power Impulse Magnetron Sputteringundersöks för användning i ett nytt framdrivningssystem för rymdfarkoster: BPHiPIMSthrusters. Intresset för BP-HiPIMS har ökat den senaste tiden inomtunnfilmsfysiken på grund av accelerationen av “target” joner som tros accelererasav den bipolära pulsen som följer den vanliga HiPIMS pulsen. Denna accelerationskulle också kunna användas för att skapa en framdrivande kraft som kan användassom motor på rymdfarkoster, där saknaden av accelererande galler och separationav jonisering och acceleration i tiden är attraktiva fördelar av det föreslagnasystemet. I denna rapport undersöks den fysikaliska processen och viktiga parametrarexperimentellt för att få en förståelse för jonaccelerationsprocessen med målet attverifiera teorin bakom “BP-HiPIMS thrusters”.Genom plasmapotentialmätningar kan en gynnsam potentialstruktur, mellan denmagnetiska fällan nära magnetronen och volymenutanför, som potentiellt kan accelerera joner uppmätas under vissa förhållanden, däracceleration av joner bekräftas av masspektrometri. Resultaten är lovande för ettelektriskt rymdframdrivningssystem, men ytterligare forskning krävs för att evaluerakonkurrenskraften av det föreslagna systemet.

In this work, the data analysis of oscillating flapping fins is conducted for mathematical model. Data points of heave and surge force obtained by the CFD (Computational Fluid Dynamics) for different geometrical kinds of flapping fins. The fin undergoes a combination of vertical and angular oscillatory motion, while travelling at constant forward speed. The surge thrust and heave lift are generated by the combined motion of the flapping fins, especially due to the carrier vehicle’s heave and pitch motion will be investigated to acquire system identification with CFD data available while the fin pitching motion is selected as a function of fin vertical motion and it is imposed by an external mechanism. The data series applied to model unsteady lifting flow around the system will be employed to develop an optimization algorithm to establish an approximation transfer function model for heave force and obtain a predicting black box system with nonlinear theory for surge force with fin motion control synthesis.

The present work proposes a methodology to define the electric propulsion system for PSVs. This methodology was applied to a case study: the conceptual design of a PSV for operation at the pre-salt fields at Santos basin. First, four different alternatives of electric propulsion systems for the PSV are presented and sized. The first one has induction motors as main propulsion motors, the second one has synchronous motors as main propulsion motors; the third and fourth alternatives are the same as the first and second, respectively, with a batteries bank connected to the main switchboard. Each of the four arrangements was contemplated with two options for Diesel generators: high speed and medium speed generator sets. The mass, volume, fuel consumption, exhaust gases emissions and reference capital costs for each arrangement are estimated and analyzed. Moreover, an economic analysis through the Net Present Value (NPV) is performed. The methodology ends with the Analytic Hierarchy Process (AHP) to support the decision making procedure. Some of the parameters obtained for each arrangement (mass, volume, fuel consumption, exhaust gases and NPV) are used as criteria and sub-criteria for selection. Two scenarios are evaluated, the first scenario gives more importance to the financial component of the design; the second scenario sets the exhaust gases emissions as the more significant parameter. The results were different, the arrangements 1 and 2 with medium speed Diesel generator sets appear as the most suitable option from the economical point of view; whereas the arrangements with batteries and high speed Diesel gensets are the best options to reduce the exhaust emissions. / O presente trabalho propôs uma metodologia para definir o sistema de propulsão elétrica para PSVs. A metodologia foi aplicada para um caso estudo: o projeto conceitual de um PSV para operar nos campos do pré-sal na Bacia de Santos. Primeiramente, as quatro diferentes alternativas de sistemas de propulsão elétrica para PSV são apresentadas e dimensionadas. A primeira alternativa tem motores de indução como motores de propulsão principal, a segunda alternativa tem motores síncronos como motores de propulsão principal; a terceira e quarta alternativas são as mesmas que a primeira e a segunda, respectivamente, com um banco de baterias conectado ao quadro principal. Cada um dos quatro arranjos foi considerado com duas opções para Diesel geradores: Diesel geradores de alta e média rotação. A massa, volumem, consumo de combustível, emissão de gases e os custos capitais de referência para cada arranjo são estimados e analisados. Adicionalmente, uma análise económica usando o Valor Presente Líquido (VPL) é feita. A metodologia finaliza com o Analytic Hierarchy Process (AHP) para apoiar o processo de escolha de alternativa. Alguns dos parâmetros obtidos para cada arranjo (massa, volumem, consumo de combustível, gases poluentes e o VPL) são utilizados como critérios de seleção. Dois cenários são avaliados, o primeiro cenário dá maior importância à parte financeira do projeto, o segundo cenário estabelece as emissões de gases poluentes como o parâmetro mais significativo. Os resultados foram diferentes, os arranjos 1 e 2 com Diesel geradores de média rotação se apresentam como a opção mais adequada desde o ponto de vista econômico; enquanto os arranjos com baterias e Diesel geradores de alta rotação são a melhor opção para reduzir as emissões de gases poluentes.

The present work proposes a methodology to define the electric propulsion system for PSVs. This methodology was applied to a case study: the conceptual design of a PSV for operation at the pre-salt fields at Santos basin. First, four different alternatives of electric propulsion systems for the PSV are presented and sized. The first one has induction motors as main propulsion motors, the second one has synchronous motors as main propulsion motors; the third and fourth alternatives are the same as the first and second, respectively, with a batteries bank connected to the main switchboard. Each of the four arrangements was contemplated with two options for Diesel generators: high speed and medium speed generator sets. The mass, volume, fuel consumption, exhaust gases emissions and reference capital costs for each arrangement are estimated and analyzed. Moreover, an economic analysis through the Net Present Value (NPV) is performed. The methodology ends with the Analytic Hierarchy Process (AHP) to support the decision making procedure. Some of the parameters obtained for each arrangement (mass, volume, fuel consumption, exhaust gases and NPV) are used as criteria and sub-criteria for selection. Two scenarios are evaluated, the first scenario gives more importance to the financial component of the design; the second scenario sets the exhaust gases emissions as the more significant parameter. The results were different, the arrangements 1 and 2 with medium speed Diesel generator sets appear as the most suitable option from the economical point of view; whereas the arrangements with batteries and high speed Diesel gensets are the best options to reduce the exhaust emissions. / O presente trabalho propôs uma metodologia para definir o sistema de propulsão elétrica para PSVs. A metodologia foi aplicada para um caso estudo: o projeto conceitual de um PSV para operar nos campos do pré-sal na Bacia de Santos. Primeiramente, as quatro diferentes alternativas de sistemas de propulsão elétrica para PSV são apresentadas e dimensionadas. A primeira alternativa tem motores de indução como motores de propulsão principal, a segunda alternativa tem motores síncronos como motores de propulsão principal; a terceira e quarta alternativas são as mesmas que a primeira e a segunda, respectivamente, com um banco de baterias conectado ao quadro principal. Cada um dos quatro arranjos foi considerado com duas opções para Diesel geradores: Diesel geradores de alta e média rotação. A massa, volumem, consumo de combustível, emissão de gases e os custos capitais de referência para cada arranjo são estimados e analisados. Adicionalmente, uma análise económica usando o Valor Presente Líquido (VPL) é feita. A metodologia finaliza com o Analytic Hierarchy Process (AHP) para apoiar o processo de escolha de alternativa. Alguns dos parâmetros obtidos para cada arranjo (massa, volumem, consumo de combustível, gases poluentes e o VPL) são utilizados como critérios de seleção. Dois cenários são avaliados, o primeiro cenário dá maior importância à parte financeira do projeto, o segundo cenário estabelece as emissões de gases poluentes como o parâmetro mais significativo. Os resultados foram diferentes, os arranjos 1 e 2 com Diesel geradores de média rotação se apresentam como a opção mais adequada desde o ponto de vista econômico; enquanto os arranjos com baterias e Diesel geradores de alta rotação são a melhor opção para reduzir as emissões de gases poluentes.

This thesis deals with the experimental and numerical analysis of the water hammer phenomenon generated by the discharge of a pressurized liquid into a pipeline kept under vacuum conditions. This flow configuration induces several multiphase phenomena such as cavitation and gas desorption that cannot be ignored in the water hammer behavior.<p><p>The motivation of this research work comes from the liquid propulsion systems used in spacecrafts, which can undergo fluid hammer effects threatening the system integrity. Fluid hammer can be particularly adverse during the priming phase, which involves the fast opening of an isolation valve to fill the system with liquid propellant. Due to the initial vacuum conditions in the pipeline system, the water hammer taking place during priming may involve multiphase phenomena, such as cavitation and desorption of a non-<p>condensable gas, which may affect the pressure surges produced in the lines. Even though this flow behavior is known, only few studies model the spacecraft hardware configuration, and a proper characterization of the two-phase flow is still missing. The creation of a reliable database and the physical understanding of the water hammer behavior in propulsion systems are mandatory to improve the physical models implemented in the numerical codes used to simulate this flow configuration.<p><p>For that purpose, an experimental facility modeling a spacecraft propulsion system has been designed, in which the physical phenomena taking place during priming are generated under controlled conditions in the laboratory using inert fluids. An extended experimental campaign was performed on the installation, aiming at analyzing the effect of various working parameters on the fluid hammer behavior, such as the initial pressure in the line, liquid saturation with the pressurant gas, liquid properties and pipe configuration. The influence of the desorbed gas during water hammer occurrence is found to have a great importance on the whole process, due to the added compressibility and lower speed of sound by an increasing amount of non-condensable gas in the liquid + gas mixture. This results in lower pressure levels and faster pressure peaks attenuation, compared to fluids without desorption. The two-phase flow was characterized by means of flow visualization of the liquid front at the location where the fluid hammer is generated. The front arrival was found to be preceded by a foamy mixture of liquid, vapor and non-condensable gas, and the pressure wave reflected at the tank may induce the liquid column separation at the bottom end. While column separation takes place, the successive pressure peaks are generated by the impact of the column back against the bottom end.<p><p>The resulting experimental database is then confronted to the predictions of the 1D numerical code EcosimPro/ESPSS used to assess the propulsion system designs. Simulations are performed with the flow configuration described before, modeling the experimental facility. The comparison of the numerical results against the experimental data shows that aspects such as speed of sound computation with a dissolved gas and friction modeling need to be improved. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

L’effet Biefeld-Brown, du nom de ses découvreurs dans les années 1920, désigne la force électrohydrodynamique (EHD) s’appliquant sur deux électrodes sous haute tension dans l’air. Si l’origine de cette force a pu faire l’objet de certaines spéculations, il est aujourd'hui admis qu’elle repose sur l’accélération par un fort champ électrique d’un volume d’air partiellement ionisé. Cet effet aussi appelé vent ionique intéresse diverses applications : contrôle actif d’écoulement, augmentation du transfert de chaleur par convection forcée, séchage de denrées alimentaires ou encore la propulsion. Cette thèse, présente une étude expérimentale, théorique et numérique du vent ionique dans une configuration modèle à deux électrodes parallèles. Le faible rendement du vent ionique l’a écarté des applications à la propulsion mais des expériences récentes menées en 2013 montrent qu’il permet d’atteindre un rapport poussée/puissance étonnement élevé. Nous montrons dans une première partie, à partir de mesures et de considérations aérodynamique générales que la poussée générée pourrait suffire à contrebalancer la force de traînée pour certains aéronefs ultra-légers. Ces mesures ont permis de quantifier la force EHD et sa dépendance avec la géométrie des électrodes. En outre, la meilleure configuration à deux collecteurs peut produire une poussée presque deux fois plus importante qu’une configuration avec un seul collecteur, à tension fixée. Ces premiers résultats ont été affinés dans un second temps par les mesures PIV qui ont permis la reconstruction de l’écoulement et du champ de force entre les électrodes. Les vitesses mesurées dépassent rarement 3 m/s, et la force volumique est de l’ordre de 10 N/m 3. L’origine physique de la configuration optimale à deux collecteurs a été éclaircie par la mise en évidence des structures de sillages et de leurs effets instationnaires. Par ailleurs, une analyse théorique générale de la force propulsive nous a permis de confirmer sa dépendance explicite avec le rapport courant sur mobilité ionique. Le courant étant directement lié à la physique de la décharge couronne, la seconde partie de la thèse s’est concentrée sur son analyse théorique et numérique. Une analyse asymptotique a ainsi permis de trouver une expression analytique du champ électrique critique et de la caractéristique courant-tension permettant de connaître l’influence de la densité du gaz et de sa composition sur le courant produit dans des électrodes concentriques. Cette approche asymptotique a été associée à une formulation de décomposition de domaine dans le cadre d’une discrétisation par éléments finis pour analyser des configurations plus générales. Une résolution itérative du système d’équations stationnaires non-linéaire couplées par méthode de Newton est proposée, testée et validée. Cette méthode peut être étendue à des géométries plus complexes, permettant ainsi d’obtenir une condition d’injection des charges prenant en compte la physique complexe de la décharge. / The Biefeld-Brown effect, named after its discoverers in 1920s, stands for the electrohydrodynamic (EHD) force applied on two high voltage electrodes in air. The origin of this force has been subject to controverse, but it is establised that it relies on the acceleration of ionized air by a strong electric field. Numerous applications are associated with ionic wind : active flow control, heat transfer enhancement, food drying or even propulsion. At the first glance, the low efficiency is unattractive for propulsion. However recent experiments highlighted a surprisingly high thrust/power ratio. This PhD research aimed to better understand the phenomena, through experiments and theoretical or numerical analysis. First, an experimental study was carried out to quantify the EHD force and its variations with the geometry of the electrodes. For instance, the best position of two collecting electrodes could produce nearly twice more thrust than the one collector configuration, for a given applied voltage. Considering the mass and the aerodynamic of some already existing very light aircrafts, it is shown that the produced thrust could at most balance the aerodynamic drag. This first results were enhanced by PIV measurements, which gave deeper insight into the flow and the force field between the electrodes. The air speed recorded was at most around 3 m/s, while the volumetric force of the order of 10 N/m3. The physical explaination of the optimal two collectors configuration relied partially on the wake flow structures and their unsteady effects. Then, a theoretical analysis of the propulsive force confirmed its explicit dependence on the current to mobility ratio. The discharge current being determined by the corona discharge physics, the second part of this work focuses on its theoretical and numerical analysis. An asymptotic approach of the corona discharge for concentric cylindrical electrodes led to an explicit expression of both the onset surface electric field and the current-voltage law as functions of the gas density, the effective ionization coefficient and the electrodes size. This asymptotic approach was reformulated in the frame of a domain decomposition method, implemented numerically with a finite elements discretization, in order to generalize the asymptotic approach. The iterative algorythm for the steady non-linear coupled system of equations is based on Newton method. This method provides a physically relevant boundary condition for the charge injection and can be applied to more complex geometries.

Les recherches menées au cours de cette thèse ont pour but de converger vers la synthèse de molécules énergétiques, possédant un squelette polyazoté, destinées à la propulsion spatiale ou militaire. En effet, les systèmes propulsifs utilisés à l’heure actuelle reposent sur des technologies, certes fiables, mais souffrant de limites de performance voire d’incompatibilité quant à la réglementation européenne REACH. Il devient nécessaire, pour que les lanceurs européens conservent leur première position mondiale dans le domaine de la mise en orbite de satellites publics ou privés, de se doter de nouveaux propergols plus performants. C’est ainsi que nous avons orienté ce travail vers la synthèse de composés appartenant à la famille des « HEDM » (High Energetic Density Material), composés possédant en rupture technologique avec les solutions actuelles, et dont le développement est attendu à l’horizon 2050. Dans le cadre de cette thèse, deux cibles d’intérêt ont été identifiés : l’anion pentazolate, molécule strictement azotée aromatique de formule N5-, et le cyclopentazane, molécule inédite à ce jour, de formule N5H5. Dans une première partie nous avons étudié la synthèse de la synthèse et l’étude de divers arylpentazoles, ainsi que des voies d’oxydation et de réduction de ces précurseurs menant à l’obtention de l’anion pentazolate Puis, dans un second temps nous nous sommes intéressés aux synthèses et aux études de stabilités de composés polyazotés de type triazane et azimine. Ces composés ont ensuite été utilisés à des réactions de cycloadditions [3+2] menant à la synthèse du cyclopentazane. Enfin, nous avons regardé les différents modes de complexation possible entre ces composés polyazotés et des complexes métalliques / The research carried during this PhD aims to synthesis new compounds with polynitrogen-backbone suitable for spacecraft or military propulsion. Indeed, the actual spacecraft uses a technology which is reliable, but with some limitation with their energetic efficiency and to satisfy the REACH regulation. It is necessary, for the Europeans launcher to stay at the first position in public or private satellites launch world wild, to find new and more efficient propellant. So, this work was focused on the synthesis of “HEDM” (High Energetic Density Material) compounds, which possess much higher propulsive features than the actual propellants. This could lead to a breakthrough in spacecraft propulsion in the next 30 years.For this PhD work two compounds of interest were identified: the pentazolate anion, which is an all nitrogen aromatic compound with a formula of N5-, and the cyclopentazan, which is an original polynitrogen compound with a formula of N5H5. First, we focused our work on the synthesis of various arylpentazoles followed by oxidative or reductive ways which lead to the pentazolate anion. Secondly, we synthesised and the studied the stability of polynitrogen-based compound, triazanes and azimines. Those compounds were then used in trials of cycloadditions which will lead to the cyclopentazan. Finally, we studied various way of complexing our polynitrogen-compound with various metallic complexes

Les Moteurs à Propergol Solide sont le siège d'instabilités de combustion qui se manifestent par des fluctuations de la pression interne et, en conséquence, de la poussée induite. Les phénomènes oscillatoires observés résultent d'un couplage entre l'acoustique de la chambre de combustion et une ou plusieurs instabilités hydrodynamiques de l'écoulement interne.Dans cette thèse, on s'intéresse à l'étude de l'écoulement induit par injection pariétale en géométrie axisymétrique. Plus particulièrement, on se concentre sur l'interaction qui peut avoir lieu entre cet écoulement et une structure : les Protections Thermiques de Face.Une étude expérimentale reposant sur le montage gaz froid VALDO de l'ONERA, modélisation représentative des MPS P230, a permis d'examiner l'influence d'obstacles, rigides et en élastomère, sur les instationnarités de l'écoulement. Le caractère instable de l'écoulement induit par injection pariétale est alors confirmé et le rôle primordial joué par les PTF sur les fréquences émergeant au sein de l'écoulement a été identifié.L'analyse de stabilité linéaire de l'écoulement, conduite en approche globale, permet l'étude de sa dynamique en tant qu'amplificateur de bruit. Les m¶mécanismes mis en jeu dans l'instabilité de l'écoulement induit par injection pariétale ainsi que son interaction complexe avec la couche de cisaillement issue de l'obstacle sont analysés. La réponse de l'écoulement à un forçage harmonique est alors examinée à la lumière des résultats expérimentaux.Cette étude a été complétée par une approche numérique de l'Interaction Fluide-Structure sur une configuration jugée critique. Une étape préliminaire à la simulation multi-physique est l'élaboration d'un modèle réaliste du comportement des PTF en élastomère. L'identification et la prise en considération des mécanismes propres aux élastomères dans la loi de comportement est ainsi détaillée. Les résultats issus des simulations sont confrontés aux résultats expérimentaux et rendent possible la validation d'un scénario de couplage dédié à l'Interaction Fluide-Structure au sein des MPS. / Fluid Structure Interaction of an inhibitor with the internal flow induced by wall injection was studied in an axisymmetric cold flow apparatus. Experiments were carried out over a wide range of injection velocities in order to underline how the obstacle not only modifies the mean flowfield but also its entire dynamic behaviour.The resulting instability (from the interaction of the unstable shear layer with the Taylor-Culick flow) exhibits a significant shift with respect to the Taylor-Culick instability and therefore emphasizes the strong impact of the inhibitor on hydrodynamics.The mecanisms responsible of such behaviour are studied in this thesis with the help of global linear stability analysis and multi-physics numerical computations.

The CubeSat community has begun to develop and implement propulsion systems. This movement represents a new capability which may satisfy mission needs such as orbital and constellation maintenance, formation flight, de-orbit, and even interplanetary travel. With the freedom and capability granted by propulsion systems, CubeSat providers must accept new responsibilities in proportion to the potential hazards that propulsion systems may present. The Cal Poly CubeSat program publishes and maintains the CubeSat Design Specification (CDS). They wish to help the CubeSat community to safety and responsibly expand its capabilities to include propulsive designs. For this reason, the author embarked on the task of developing a draft of safety standards CubeSat propulsion systems. Wherever possible, the standards are based on existing documents. The author provides an overview of certain concepts in systems safety with respect to the classification of hazards, determination of required fault tolerances, and the use of inhibits to satisfy fault tolerance requirements. The author discusses hazards that could exist during ground operations and through launch with respect to hazardous materials and pressure systems. Most of the standards related to Range Safety are drawn from AFSPCMAN 91-710. Having reviewed a range of hypothetical propulsion system architectures with an engineer from Range Safety at Vandenberg Air Force Base, the author compiled a case study. The author discusses many aspects of orbital safety. The author discusses the risk of collision with the host vehicle and with third party satellites along with the trackability of CubeSats using propulsion systems. Some recommendations are given for working with the Joint Functional Component Command for Space (JFCC SPACE), thanks to the input of two engineers who work with the Joint Space Operations Center (JSpOC). Command Security is discussed as an important aspect of a mission which implements a propulsion system. The author also discusses End-of-Life procedures such as safing and de-orbit operations. The orbital safety standards are intended to promote “good citizenship.” The author steps through each proposed standard and offers justification. The author is confident that these standards will set the stage for a dialogue in the CubeSat community which will lead to the formulation of a reasonable and comprehensive set of standards. The author hopes that the discussions given throughout this document will help CubeSat developers to visualize the path to flight readiness so that they can get started on the right foot.

This study explores the variable speed operation and shift response of a prototype of a two speed single path CVT rotorcraft driveline system. Here a Comprehensive Variable Speed Rotorcraft Propulsion system Modeling (CVSRPM) tool is developed and utilized to simulate the drive system dynamics in steady forward speed condition. This investigation attempts to build upon previous variable speed rotorcraft propulsion studies by: 1) Including fully nonlinear first principles based transient gas-turbine engine model 2) Including shaft flexibility 3) Incorporating a basic flight dynamics model to account for interactions with the flight control system. Through exploring the interactions between the various subsystems, this analysis provides important insight into the continuing development of variable speed rotorcraft propulsion systems.