The topic of this diploma thesis is design of a tugboat. The thesis concerns designing a tugboat while meeting basic technological, ergonomic, ecologic and aesthetic requirements while using modern technologies and manufacturing options. There is an emphasis on innovative and unconventional solution, which will differ from contemporary products.

Hybrid rocket motors have become of great international interest during the last couple of years. A hybrid rocket motor is propelled by the use of a solid fuel and a liquid oxidizer. The fundamental principle of the hybrid propelled system is that the liquid oxidizer is injected into a combustion chamber to enable the combustion of the solid fuel. The exhaust gases are then accelerated through a nozzle to supersonic velocity to produce the desired level of thrust. To describe the overall performance of a propulsion system, it is common use the specifc impulse which expresses the performance as the total impulse per mass unit of propellant. However, in order to optimize a propulsion system, it is necessary to consider the entire system with the oxidizer tank, feed system, combustion chamber and nozzle. The issue with using the specifc impulse as a performance index is that it does not consider the total mass of the propulsion system. Therefore, this thesis will instead analyze the system specifc impulse, which expresses the performance as the total impulse per mass unit of propulsion system. By studying the entire hybrid propulsion system it is possible to determine the relations between the various parameters of the diferent components and should therefore be able to optimize the mass, volume and system specifc impulse of the system. This master’s thesis aims to illustrate how the hybrid propulsion system can be optimized depending on various fxed parameters. This analysis studies a generic hybrid propulsion systemwith Hydroxyl-terminated polybutadiene (HTPB) as a solid fuel with diferent combinations ofoxidizers. Each oxidizer- and fuel confguration shall have identical combustion chamber presssures and shall generate the same total impulse. Nevertheless, each combination will result indiferent specifc impulses since the optimal confguration for each combination will generate diffferent oxidizer and fuel masses. It is then desirable to analyze how the diferent components ofthe propulsion system are affected by the required oxidizer and fuel for each optimal confgurationand how it drives the design of the system and generates diferent system specifc impulses.

<div>When combined with common fuel binders, solid hypergolic fuels can simplify the overall complexity of hybrid rocket systems, as the fuel grain can be ignited and reignited without an external power source or external fluid. In addition, with the hypergolic additive embedded in the binder, the flame zone can be placed at the surface of the grain itself, thereby providing heat to the fuel, improving fuel regression rate, and combustion stability and sustainability. Coupled with high grades of mixed oxides of nitrogen (MON), such hypergolically ignited hybrid configurations are considered a potential propulsion system for a robotic Mars Ascent Vehicle (MAV). Use of the fuel additives and a suitable choice of oxidizer allows for low temperature stability and operation of the propellants, making it an appealing candidate for a simple and storable hybrid propulsion system.</div><div>The first half of this work is dedicated to a very application based study of paraffin based hypergolic hybrids, while the second half of this work, independent from the first, focuses on how theory could help in developing future hypergolic propulsion systems.</div><div>The process undertaken to develop a paraffin based hypergolic hybrid relied heavily on experimental testing of a wide variety of additive loaded fuels with MON to optimize hybrid motor grain parameters with the goals of minimizing ignition delay, improving combustion stability, and promoting sustainment of the flame. MON 3 and MON 25 (3 wt.% or 25 wt.% nitric oxide mixed with nitrogen tetroxide) were used as oxidizers. Through an initial screening process, we selected two solid hypergolic propellants, sodium amide and potassium bis(trimethylsilyl)amide (PBTSA), as additives to promote hypergolic ignition given their low ignition delays with both grades of MON. Iterations on the grain configuration consisted in minimizing the additive loading to simplify the casting process and increase performance, without losing hypergolicity of the grain or hampering combustion sustainability. Using a 90 wt.% hypergolic additive front segment, we were able to light the grain three times using the hypergolic reaction between the additives and MON 3. Once relights achieved, we mainly focused on demonstrating sustained combustion, and determined that, once the front segment depleted, the lack of heat in the system lead the motor to shut down prior to the end of the targeted burn. This led us to add a reactive additive, sodium borohydride, in the main grain, as a way to generate heat in the motor once the front segment was depleted. With the objective of testing relevant conditions for an actual Mars Ascent Vehicle, one of our final tests was done in an altitude chamber, at a 100,000 ft targeted simulated altitude (equivalent to the atmospheric pressure on Mars), with MON 25 as the oxidizer. Using a mixture of sodium amide, PBTSA, and sodium borohydride, we were able to achieve hypergolic ignition in 425 ms (delay to reach 90% of the maximum chamber pressure) at 102,000 ft simulated altitude, for an average chamber pressure of 113 psia.</div><div>During testing we determined that an ideal solid additive should exhibit both low ignition delay with the oxidizer considered, to minimize the motor start up time, and a high heat of combustion, to maximize the energy release and therefore maximize performance. However, the lack of data and theoretical understanding of the reactivity of MONs with non hydrazine based fuels made it challenging to find such an ideal solid additive. Historically, screening processes for new fuel candidates, liquids or solids, have followed a “hit or miss” approach, in which potential fuels were selected based on common characteristics with known hypergols, which is the approach we followed during the development of the hypergolic hybrid. A more robust approach, typically used in the biology and chemistry fields, can be used to predict reactivity of chemicals using statistical analysis. A quantitative structure activity relationship (QSAR) analysis is a statistical analysis used to correlate reactivity to selected molecular descriptors, or properties. Using this approach, one can create models, determined during the QSAR analysis, to predict reactivity of fuel candidates, solely based on their properties. Combined with the recent advancements in computational chemistry and computation of properties, this simple approach has the potential to greatly simplify screening processes for new fuel candidates, as experimental data is not needed anymore. With this method, we were able to fit the logarithmic of the minimum ignition delay for 30 different amines using seven molecular descriptors (heat of formation, heat of vaporization, highest occupied molecular orbital, charge on the nitrogen, rotatable bond count, and ovality), for an R² value of 0.70. While the main motivation behind starting this theoretical work was to optimize for solid additives properties for the hypergolic hybrid configuration described previously, the potential of such model extends to a wider range of propulsion systems (reaction control systems, orbital maneuvering, etc.), and could be expanded to a wider range of oxidizers using machine learning.</div>

To mitigate climate change, all sectors must contribute their part. Electric propulsion system is a promising approach to reduce emissions from the aviation industry. A major challenge is however the low energy density in today’s battery technology. Even with today’s leading li-ion batteries, the specific energy density in jet fuel is 48 times larger. Because of the low energy density in any battery technology today, hybrid electric propulsion system could be a bridge between conventional and fully electric propulsion systems. The purpose of this degree project is to explore different designs of a parallel hybrid electric mixed turbofan to minimize the impact aircraft have on the environment. The engine has been designed in Modelon Impact and MATLAB has been used to evaluate the thrust requirement and, the performance and weight calculation of the electrical power system. Furthermore, the conventional engine was validated against GasTurb. Three different designs were evaluated, i.e., design #1 (reference engine with hybridization), #2 (decreased OPR) and #3 (increased BPR and decreased FPR) with two different weights of the electrical power system. None of the designs showed a reduction in terms of the total fuel consumption during the whole mission profile. However, design #3 showed the most beneficial results in terms of reducing the specific fuel consumption and could reduce the fuel consumption in the climb segment the most among the three different designs.

To access and operate in space, a wide range of propulsion systems has been developed, from high-thrust chemical propulsion to low-thrust electrical propulsion, and new kind of systems are considered, such as solar sails and nuclear propulsion. Recently, interest in hybrid rocket engines has been renewed due to their attractive features (safe, cheap, flexible) and they are now investigated and developed by research laboratories such as ONERA.This master’s thesis work is in line with their development at ONERA and aims at finding a methodology to study numerically the liquid oxidizer injection using a Lagrangian solver for the liquid phase. For this reason, it first introduces a model for liquid atomiser developed for aeronautical applications, the FIMUR model, and then focuses on its application to a hybrid rocket engine configuration.The FIMUR model and the Sparte solver have proven to work fine with high mass flow rates on coarse grids. The rocket engine simulations have pointed out the need of an initialisation of the flow field. The methodology study has proven that starting with a reduced liquid mass flow rate is preferable to a simulation with a reduced relaxation between the coupled solvers. The former could not be brought to conclusion due to lack of time but gives an encouraging path to further investigate.

I samband med den globala uppvärmningen ökar efterfrågan för rena och förnybara bränslen alltmer i dagens samhälle. Eftersom flygindustrin idag är ansvarig för samma mängd växthusgaser som all motortrafik i Sverige, skulle ett byte till en avgasfri energikälla för flygfarkoster vara ett stort framsteg. Därför har projektet genom modellering framtagit ett hybridsystem av ett batteri och en bränslecell och undersökt hur kombinationen av olika storlekar på dem presterar i en driftcykel. Då batterier har hög specifik effekt men är tunga, kompletteras de med fördel av bränsleceller, som är lättviktiga och bidrar med uthållig strömförsörjning. På så sätt blir hybriden optimal för flygfarkoster. Kandidatarbetet är en del av projektet Green Raven, ett tvärvetenskapligt samarbete mellan instutitionerna Tillämpad Elektrokemi, Mekatronik och Teknisk Mekanik på Kungliga Tekniska Högskolan. Driftcykelmodelleringen gjordes i Simulink, och flera antaganden gjordes beträffande effektprofilen, samt bränslecellens mätvärden och effekt. Tre olika energihushållningsscheman skapades, vilka bestämde bränslecellseffekten beroende på vätgasnivån och batteriets laddningstillstånd. Skillnaden på systemen var vilka intervall av laddningstillstånd hos batteriet som genererade olika effekt hos bränslecellen.  Det bästa alternativet visade sig vara 0/100-systemet, eftersom det var det enda som inte orsakede någon degradering av bränslecellens kapacitet. / In today’s society, with several environmental challenges such as global warming, the demand for cleanand renewable fuels is ever increasing. Since the aviation industry in Sweden is responsible for the sameamount of greenhouse gas emissions as the motor traffic, a change to a non-polluting energy source forflying vehicles would be considerable progress. Therefore, this project has designed a hybrid system of abattery and a fuel cell and investigated how different combinations of battery and fuel cell sizes perform ina drive cycle, through computer modelling. As batteries possess a high specific power but are heavy, thefuel cells with high specific energy complement them with a sustained and lightweight power supply,which makes the hybrid perfect for aviation. The bachelor thesis is a part of Project Green Raven, aninterdisciplinary collaboration with the institutions of Applied Electrochemistry, Mechatronics andEngineering Mechanics at KTH Royal Institute of Techology. The drive cycle simulations were done inSimulink, and several assumptions regarding the power profile, fuel cell measurements and power weremade. Three different energy management strategies were set up, determining the fuel cell powerdepending on hydrogen availability and state of charge of the battery. The strategies were called 35/65,20/80 and 0/100, and the difference between them was at which state of charge intervals the fuel cellchanged its power output. The best strategy proved to be 0/100, since it was the only option which causedno degradation of the fuel cell whatsoever.

The rapidly expanding space sector is at the forefront of innovation. New technologies are been continuously developed to allow more availability of space for a multitude of commercial or scientific goals. The same is especially true for the field of Space propulsion, where the focus is towards more compact and greener solutions, for launchers, satellites and landers. One of the most suitable candidates for chemical propulsion is the use of liquid oxygen in combination with liquid hydrogen, which, however, comes with many drawbacks connected primarily to the low energetic density of liquid hydrogen and the complexity of storing cryogenics. An innovative solution to this challenge comes with the use of Metal oxidation or metal combustion reaction. This implies the use of the reaction between air and metals or between water and metals to generate heat, power and hydrogen. This allows for much easier power generation since metal powders are simple to stock and have a much higher density than hydrogen. Therefore, the process is compact and completely renewable. The technology has undoubted potential for space applications too. The high energy density, the lack of cryogenics, the high availability and the re-usability make this technology suitable for power generation purposes and, in this case, for propulsive purposes. This thesis aims to explore the various applications of metal combustion, with a particular focus on space propulsion applications. The gathered literature will be then used to produce a conceptual design of a novel propulsion system which maximises the benefits of metal combustion.

The widely-used passenger and car ferries, sailing regularly and carrying heavy loads, form a unique type of marine vessel, providing vital transportation links to the coastal regions. Modern ferry ships usually are equipped with multiple diesel engines as prime movers. These diesel engines consume a large amount of marine diesel fuel with high fuel costs, and high emissions of greenhouse gas (GHG) and other harmful air pollutants, including CO2, HC, NOx, SO2, CO, and PM. To reduce fuel costs and the harmful emissions, the marine industry and ferry service providers have been seeking clean ship propulsion solutions. In this work, the model-based design (MBD) and optimization methodology for developing advanced electrified vehicles (EV) are applied to the modelling, design and control optimizations of clean marine vessels with a hybrid electric propulsion system. The research focuses on the design and optimization of the hybrid electric ship propulsion system and uses an open deck passenger and car ferry, the MV Tachek, operated by the British Columbia Ferry Services Inc. Canada, as a test case. At present, the ferry runs on the Quadra Island – Cortes Island route in British Columbia, Canada, with dynamically changing ocean conditions in different seasons over a year. The research first introduces the ship operation profile, using statistical ferry operation data collected from the ferry’s voyage data recorder and a data acquisition system that is specially designed and installed in this research. The ship operation profile model with ship power demand, travelling velocity and sailing route then serves as the design and control requirements of the hybrid electric marine propulsion system. The development of optimal power control and energy management strategies and the optimization of the powertrain architecture and key powertrain component sizes of the ship propulsion system are then carried out. Both of the series and parallel hybrid electric propulsion architectures have been studied. The sizes of crucial powertrain components, including the diesel engine and battery energy storage system (ESS), are optimized to achieve the best system energy efficiency. The optimal power control and energy management strategies are optimized using dynamic programming (DP) over a complete ferry sailing trip. The predicted energy efficiency and emission reduction improvements of the proposed new ship with the optimized hybrid propulsion system are compared with those of two benchmark vessels to demonstrate the benefits of the new design methodology and the optimized hybrid electric ship propulsion system design. These two benchmarks include a conventional ferry with the old diesel-mechanical propulsion system, and the Power Take In (PTI) hybrid electric propulsion systems installed on the MV Tachek at present. The simulation results using the integrated ship propulsion system model showed that the newly proposed hybrid electric ship could have 17.41% fuel saving over the conventional diesel-mechanical ship, and 22.98% fuel saving over the present MV Tachek. The proposed optimized hybrid electric propulsion system, combining the advantages of diesel-electric, pure electric, and mechanical propulsions, presented considerably improved energy efficiency and emissions reduction. The research forms the foundation for future hybrid electric ferry design and development. / Graduate

Ce travail de thèse s'inscrit dans le cadre du projet CNES-PERSEUS. L’objectif principal est l’étude et la caractérisation d’un béton réfractaire à base de carbure de silicium, avec une taille maximale d'agrégats de 800 microns, dans un environnement de type propulsion hybride. Le col de la tuyère doit résister à un environnement très oxydant, produit par la combustion de polyéthylène solide et de protoxyde d’azote liquide, avec des températures statiques de gaz qui peuvent atteindre 2800K. L’étude est divisée en trois parties : une caractérisation thermomécanique du matériau jusqu’à 1500K ; une étude du comportement à l’oxydation en atmosphère standard, sous un flux solaire maximal de 15 MW/m2 ; des tests au banc avec un moteur hybride à l'ONERA, sur des tuyères conçues et réalisées au laboratoire ICA. Le frittage et la céramisation du microbéton engendrent une densification du matériau et le passage de liaisons de type hydrauliques à des liaisons de type covalentes et ioniques, avec augmentation du module d'élasticité et de la contrainte à la rupture à haute température. Ce matériau présente un comportement visco-élastique-plastique aux hautes températures : il reste majoritairement élastique linéaire jusqu'à la température de stabilisation du matériau, puis une composante viscoplastique apparaît, provoquée par la formation de phases liquides à partir de la matrice cimentaire. Les tests d’oxydation à haute température ont été menés au laboratoire PROMES-CNRS, sur une installation solaire de 2 kW, permettant d'appliquer à un flux maximal de 15 MW/m2. Des observations MEB, en microscopie optique et des analyses EDS ont été menées pour étudier les évolutions microstructurales et la cinétique d’oxydation du matériau. Les tests d’oxydation à 15 MW/m2 ont montré des vitesses d'érosion maximales de l'ordre de 5 microns/s pour une température de 2800 K. L'érosion est générée par l'oxydation active et par la sublimation du carbure de silicium. L'oxydation active se développe à partir de 2100 K, avec formation de SiO et CO gazeux. La sublimation du carbure de silicium, à partir de 2600-2700 K, entraine la formation de Si, Si2C et SiC2 gazeux. Les essais menés sur les tuyères montrent une bonne résistance du matériau après 20 secondes de tir. Une vitesse d'ablation moyenne proche de 60 microns/s a été observée au col de la tuyère. Le comportement thermo-élastique-ablatable a été modélisé tout d'abord sur la base d'une géométrie cylindrique multicouche, puis étendue au cas de la tuyère expérimentale testée au banc d'essai. / This research is part of the PERSEUS project, a space program concerning hybrid propulsion and supported by CNES. The main goal of this study is to characterize a silicon carbide based micro-concrete with a maximum aggregates size of 800 microns, in a hybrid propulsion environment. The nozzle throat has to resist to a highly oxidizing polyethylene/N2O hybrid environment, under temperatures ranging from room temperature up to 2800K. The study is divided in three main parts: the first one deals with the thermo-mechanical characterization of the materials up to 1500K, the second one with an investigation on the oxidation behaviour in a standard atmosphere, under a solar flux up to 15 MW/m2, the last part deals with the conception, the realization and the test of three nozzles in a hybrid rocket motor at ONERA. Elastic modulus was determined by resonant frequency method: results show an increase with the stabilisation temperature. Four points bending tests have shown a rupture tensile strength increasing with stabilization temperature, up to 1500 K. Sintering and ceramization process are primary causes of this phenomenon. Visco-plastic behaviour appears at 1400 K on a material staiblized at the same temperature, due to the formation of liquid phases in cement ternary system. High-temperature oxidation in air was carried out at PROMES-CNRS laboratory, on a 2 kW solar furnace, with a maximum solar flux of 15 MW/m2. Optical microscopy, SEM, EDS analyses were used to study the microstructure evolution and the mass loss kinetics, with a maximal erosion speed of 5 microns second. During theses tests, silicon carbide undergoes active oxidation at 2100 K, with production of SiO and CO smokes and ablation. SiC sublimation is observed since 2600-2700 K, with Si, Si2C and SiC2 vapour generation. Test performed on nozzle in hybrid rocket motors at ONERA, showed an average ablation speed at nozzle throat of 60 microns second, after 20 seconds of test. Thermo-elastic-ablative behaviour has been modelled using first composite cylinder geometry, and then it has been extended to the experimental nozzle geometry, tested on the test bench.

no / Formal modelling is essential for precisely defining, understanding and reasoning when designing complex systems, such as cyberphysical systems. In this paper we present a formal specification using Event-B and Rodin platform for a case study of a cruise control system for a hybrid propulsion vehicle and electric bicycle (e-Bike). Our work uses the EventB method, a formal approach for reliable systems specification and verification, being supported by the Rodin platform, based on theorem proving, allowing a stepwise specification process based on refinement. We also use, from the same platform, the ProB model checker for the verification of the B-Machine and iUML plug-in to visualize our model. This approach shows the benefits of using a formal modelling platform, in the context of cyberphysical systems, which provides multiple ways of analysing a system. / Romanian National Authority for Scientific Research, CNCS-UEFISCDI, project number PN-III-P4-ID-PCE-20160210.