Après une dizaine d'années de recherche dans le domaine de la modélisation des plasmas froids hors-équilibre, j'ai souhaité synthétiser les principaux résultats obtenus durant cette période dans le domaine de la propulsion à plasma en vue de l'obtention de mon Habilitation à Diriger des Recherches. Je présente également dans ce document quelques pistes intéressantes à investiguer dans le domaine de la propulsion à plasma au sens large. J'ai choisi de diviser le document en trois parties distinctes, la première synthétise mes activités de recherche et présente les grandes lignes de mon projet de recherche, la seconde regroupe un certain nombre d'informations complémentaires me concernant, la dernière regroupe les publications les plus significatives. Je tiens à exprimer ma plus profonde gratitude à tous les étudiants dont j'ai encadrés les travaux de recherche ainsi qu'à l'ensemble de mes collègues pour toutes les discussions fructueuses et conseils prodigués tout au long de cette période. Je tiens également à remercier chaleureusement l'ensemble des membres du jury pour avoir examiné mes travaux. Je vous souhaite une bonne lecture !

Les machines électriques deviennent le mode principal de propulsion des navires civils depuis quelques années car elles présentent de nombreux avantages. Cependant, l'application aux bâtiments militaires pose des problèmes de discrétion magnétique, notamment pour la lutte anti-mines. Le but de cette thèse est par conséquent de déterminer les champs magnétiques émis par une machine électrique. L'étude et la connaissance de ces champs permettent alors de les compenser de manière à rendre la machine magnétiquement discrète. La solution réside dans un système de compensation externe composé de bobines alimentées judicieusement selon les champs rotorique et statorique de la machine.

<p>This thesis project has been carried out at Linköpings universitet at the Department of Mechanical Engineering. The emphasis of the project lies in the exploration of automatic selection of components for a propulsion kit. Specifically for this project, propulsion based on electric power and meeting the requirements for use in a Micro Aerial Vehicle (MAV). The key features include a systematic selection method based on user criterias and a model for evaluating propeller performance. These are implemented in a program written as a part of the project. The conclusion is that it is possible to make a program capable of a component selection and that the programs usability is mainly reliant on three factors: model for propeller evaluation, method of selection and the quality of the component database.</p>

An aircraft will encounter freezing rain, snow, and ice during ground operation and flight. In cold conditions, ice may form on th einlet and internal stators and rotors of the gas turbine engine. When ice accumulates on blades (and/or stators), the aerodynamic characteristics of the blades change due to the altered size, shape, and roughness. This change causes the blade to no longer operate at its design point and decreases compressor performance. Therefore, characterization of the aerodynamic performance is required to define the associated losses due to the effects of supercooled liquid water ingestion. This characterization can be accomplished through analysis and test. This research developed an analysis method to calculate the aerodynamic changes on a blade due to ice accumulation and the associated degradation in performance.

The use of aluminum as an energetic additive in solid rocket propellants has been around since the 1950’s. Since then, much research has been done both on the aluminum material itself and on chemical techniques to properly prepare aluminum particles for injection into a solid propellant. Although initial interests in additives were centered on space limited applications, performance increases opened the door for higher performance systems without the need to remake current systems. This thesis aims to compare the performance for aluminized solid rocket motors and non-aluminized motors, as well as focuses on design considerations for a thrust stand that can be created easily at low cost for initial testing. A theoretical model is created for predicting propellant performance and the results are compared with experimental data taken from the thrust stand as well as existing data. What is seen at the end of testing is the non-aluminized grains follow the same trends as previously conducted tests and firings. The aluminized grains follow their expected trend but at a lower performance level due to grain degradation. However, the aluminized grains still show a specific impulse increase of 6%-23% over the non-aluminized grains.

The Canadian Nanosatellite Advanced Propulsion System is the second generation cold-gas propulsion system. Its purpose is to provide the millinewton thrust required for formation control of nanosatellites, in particular the CanX-4/-5 formation flying mission. Additionally, to inject nanosatellites into orbit, a reliable and robust deployer is needed to bridge the gap between the launch vehicle and space. This bridge is the XPOD, the eXoadaptable PyrOless Deployer. Both of these technologies are designed and developed by the Space Flight Lab. This thesis describes the assembly, integration and preliminary testing of the CanX-4/-5 propulsion system. Emphasis is placed on the phases involved with the assembly and integration while highlighting the problems encountered and lessons learned. In addition, the mechanical analysis of the XPOD as well as its assembly and testing is described in detail.

The Canadian Nanosatellite Advanced Propulsion System is the second generation cold-gas propulsion system. Its purpose is to provide the millinewton thrust required for formation control of nanosatellites, in particular the CanX-4/-5 formation flying mission. Additionally, to inject nanosatellites into orbit, a reliable and robust deployer is needed to bridge the gap between the launch vehicle and space. This bridge is the XPOD, the eXoadaptable PyrOless Deployer. Both of these technologies are designed and developed by the Space Flight Lab. This thesis describes the assembly, integration and preliminary testing of the CanX-4/-5 propulsion system. Emphasis is placed on the phases involved with the assembly and integration while highlighting the problems encountered and lessons learned. In addition, the mechanical analysis of the XPOD as well as its assembly and testing is described in detail.

There exists wide ranging research interest in high-energy-density matter (HEDM) propellants as a potential replacement for existing industry standard fuels for liquid rocket engines. The U.S. Air Force Research Laboratory, the U.S. Army Research Lab, the NASA Marshall Space Flight Center, and the NASA Glenn Research Center each either recently concluded or currently has ongoing programs in the synthesis and development of these potential new propellants. In order to perform conceptual designs using these new propellants, most conceptual rocket engine powerhead design tools (e.g. NPSS, ROCETS, and REDTOP-2) require several thermophysical properties of a given propellant over a wide range of temperature and pressure. These properties include enthalpy, entropy, density, viscosity, and thermal conductivity. Very little thermophysical property data exists for most of these potential new HEDM propellants. Experimental testing of these properties is both expensive and time consuming and is impractical in a conceptual vehicle design environment. A new technique for determining these thermophysical properties of potential new rocket engine propellants is presented. The technique uses a combination of three different computational methods to determine these properties. Quantum mechanics and molecular dynamics are used to model new propellants at a molecular level in order to calculate density, enthalpy, and entropy. Additivity methods are used to calculate the kinematic viscosity and thermal conductivity of new propellants. This new technique is validated via a series of verification experiments of HEDM compounds. Results are provided for two HEDM propellants: quadricyclane and 2-azido-N, N-dimethylethanamine (DMAZ). In each case, the new technique does a better job than the best current computational methods at accurately matching the experimental data of the HEDM compounds of interest. A case study is provided to help quantify the vehicle level impacts of using HEDM propellants. The case study consists of the National Aeronautics and Space Administrations (NASA) Exploration Systems Architecture Study (ESAS) Lunar Surface Access Module (LSAM). The results of this study show that the use of HEDM propellants instead of hypergolic propellants can lower the gross weight of the LSAM and may be an attractive alternative to the current baseline hypergolic propellant choice.

The present study is focused on evaluating higher actinides beyond uranium that are capable of supporting power and propulsion requirements in robotic deep space and interstellar exploration. The central technology in this thesis is based on utilizing advanced actinides for direct fission fragment energy conversion coupled with magnetic collimation. Critical fission configurations are explored which are based on fission fragment energy conversion utilizing a nano-scale layer of the metastable isotope 242mAm coated on carbon fibers. A 3-D computational model of the reactor core is developed and neutron properties are presented. Fission neutron yield, exceptionally high thermal fission cross sections, high fission fragment kinetic energy and relatively low radiological emission properties are identified as promising features of 242mAm as a fission fragment source. The isotopes 249Cf and 251Cf are found to be promising candidates for future studies. Conceptual system integration, deep space mission applicability and recommendations for future experimental development are introduced.

Propulsion systems like Turboprop engines are generally designed to operate at a narrow range of optimum steady state performance conditions. However, these conditions are likely to vary in an unpredictable manner according to factors such as components aging, structural damages or even the operating environment. Over time, inefficiencies could add up and can lead to expensive fuel consumption or faster component aging. This thesis presents a self-optimizing control scheme, referred as Peak-seeking control, applied to propulsion systems similar to Turboprop engines. Using an extended Kalman filter, the Peak-seeking method is able drive the system to an optimal condition based only on measurements. No prior knowledge of the engine dynamics is required which make the Peak-seeking technique easy to implement and also allow for modularity in the engine design. This study is performed on both a turboprop and a DC motor driving a variable pitch propeller and considers several performance functions to optimize.