To see the other types of publications on this topic, follow the link: Propulsion systems.
Dissertations / Theses on the topic 'Propulsion systems'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Propulsion systems.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Lemay, Scott A. "Microelectromechanical propulsion systems for spacecraft." Thesis, Monterey, California. Naval Postgraduate School, 2002. http://hdl.handle.net/10945/5883.
Full textAbstract:
This is a survey of current research on micropropulsion options for very small satellites (less than ten kilogram). The concentration of research and performance evaluations utilize Micro Systems Technology (MST) and Micro Electromechanical Systems technology (MEMS) integrated with existing theories. State of the art methods used for the design and manufacturing of MEMS devices are included to provide a size perspective of microthruster technology. Nine viable microthruster options are presented, including a detailed performance analysis of the Pulsed Plasma Thruster. Exploration of the future role of micropropulsion in space is the influential factor benefiting research efforts on extremely small scale microthrusters. Significant background information on astrodynamics is included to assist the intended reader: a student of Engineering Science with interest in the Aerospace Propulsion Industry.
2
Lemay, Scott A. "Microelectromecanical propulsion systems for spacecraft." Monterey, California: Naval Postgraduate School, 2002. http://hdl.handle.net/10945/9767.
Full textAbstract:
Approved for public release; distribution is unlimitedThis is a survey of current research on micropropulsion options for very small satellites (less than ten kilogram). The concentration of research and performance evaluations utilize Micro Systems Technology (MST) and Micro Electromechanical Systems technology (MEMS) integrated with existing theories. State of the art methods used for the design and manufacturing of MEMS devices are included to provide a size perspective of microthruster technology. Nine viable microthruster options are presented, including a detailed performance analysis of the Pulsed Plasma Thruster. Exploration of the future role of micropropulsion in space is the influential factor benefiting research efforts on extremely small scale microthrusters. Significant background information on astrodynamics is included to assist the intended reader: a student of Engineering Science with interest in the Aerospace Propulsion Industry.
3
Cazenave, Timothee. "Peak-seeking control of propulsion systems." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44805.
Full textAbstract:
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.
4
Mejergren, Henrik. "Comparison of propeller-driven propulsion systems." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152804.
Full textAbstract:
Global warming caused by combustion of fossil fuels is a hot topic in today’s society and the world is constantly trying to makes steps towards a brighter tomorrow with stricter environmental laws and research of alternative fuels. A great propulsion system is however not great solely of it being environmental friendly, it must also achieve other requirements. A comparison using different propulsion systems and different fuel types has been made and evaluated in four different categories; power; range; cost and environmental impact. The process of scientifically compare systems using given attributes is a big part of the study and is hoped to yield inspiration to the reader to apply to their own application, not necessarily using the same categories. The result has been assembled in a matrix and depending on what category one prefers the most, different results are presented. A clear observation is a lack of range for all of the systems using electricity due to the low energy density compared to fossil fuels. Hydrogen fuel cells and ICE are however constrained by the volume required to store hydrogen but applications can surely be found where the great gravimetric energy-density can be utilized at its full potential. The future of alternative fuels and propulsion systems are looking great checking the improvements of technology on electrical components such as batteries, fuel cells and solar cells the last 10 years. The improvements not only affecting performance such as increased energy-density and power but also cost, making them more desired by the common man.
5
Friedrich, Christian. "Hybrid-electric propulsion systems for aircraft." Thesis, University of Cambridge, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708913.
Full text
6
Saunders, Thomas E. "Performance of small thrusters and propulsion systems." Thesis, Monterey, California : Naval Postgraduate School, 1990. http://handle.dtic.mil/100.2/ADA231482.
Full textAbstract:
Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, March 1990.Thesis Advisor(s): Healey, A.J. Second Reader: Reid, Glenn N. "March 1990." Description based on signature page as viewed on October 21, 2009. DTIC identifier(s): AUV(Autonomous Underwater Vehicles), thrusters, underwater vehicles, self operation, marine propellers, thrust, shipmotion, thesis. Author(s) subject terms: Autonomous Underwater Vehicle, AUV, Unmanned Untethered Underwater Vehicle, UUV, underwater vehicle systems design, propulsors, small thrusters. Includes bibliographical references (p. 73). Also available online.
7
Doulgeris, Georgios C. "Modelling & integration of advanced propulsion systems." Thesis, Cranfield University, 2008. http://hdl.handle.net/1826/2812.
Full textAbstract:
This research study focuses on the design of advanced propulsion cycles, having as
primary design goal the improvement on noise emissions and fuel consumption. In this
context, a preliminary cycle design method has been developed and applied on four novel
propulsion systems; ultra high bypass ratio, recuperated, intercooled-recuperated,
constant volume combustion turbofans. The analysis has shown significant improvement
in jet noise, and fuel consumption, as a result of high bypass ratio. Additionally, a
comparison to future fuel-optimised cycle has revealed the trade-off between noise
emissions and fuel consumption, where a reduction of ~30dBs in jet noise may be
achieved in the expense of ~10% increase of mission fuel.
A second aspect of this study is the integration of the propulsion system for improving
fan noise. A novel approach is followed, by half-embedding the turbofan in the upper
surface of the wing of a Broad Delta airframe. Such an installation aids in noise
reduction, by providing shielding to component (fan) noise. However, it leads to
significant inlet distortion levels. In order to assess the effect of installation-born
distortion on performance an enhanced fan representation model has been developed,
able to predict fan and overall engine performance sensitivity to three-dimensional
distorted inlet flow. This model that comprises parallel compressor theory and streamline
curvature compressor modelling, has been used for proving a linear relation between the
loss in fan stability margins and engine performance. In this way, the design engineer can
take into consideration distortion effects on off-design performance, as early as, at the
stage of preliminary cycle design.
8
Bost, Alexander Connor Larkin. "Materials for small-scale space propulsion systems." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112412.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 91-92).
This thesis explores a variety of materials and methods for creating emitter arrays for the ion electrospray propulsion system (iEPS), a compact, efficient, and scalable space propulsion system for use in a wide range of space missions. The increasing utilization of small, cheap, easy-to-launch satellites known as CubeSats has spurred demand for a propulsion system which exists at the nexus of high power efficiency, low mass, surface area, and volume, and high specific impulse. iEPS has demonstrated a unique potential to satisfy all of these stringent design requirements in a way no presently existing propulsion system can. The first part of this work explores utilizing microelectromechanical systems (MEMS) processing to increase the thrust density of iEPS. Silicon molds were designed and manufactured with differing emission site size and spacing. Additionally, a variety of materials were tested with the aim of forming a porous network within the molds prior to selective removal of the mold. A molded array is successfully fired as a result of these research efforts. The second part of this work explores creation of porous substrates for use with an existing laser ablation method of creating emitter arrays. The first iEPS thrusters tested in space used porous borosilicate glass emitter chips, which demonstrated shortcomings in terms of material uniformity, pore size, and ionic liquid fuel containment. This work explores materials and methods for improving all of these and demonstrates the successful firing of an array made by sintering a silicon dioxide nano-bead powder.
by Alexander Connor Larkin Bost.
S.M.
9
Schoeffler, Lara Elaine. "Orbital Dynamics of Space Nuclear Propulsion Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1618332162764726.
Full text
10
Ling, Jack C. L. "Compressors for miniature unmanned aerospace propulsion systems." Phd thesis, School of Aerospace, Mechanical and Mechatronic Engineering, 2009. http://hdl.handle.net/2123/6430.
Full text
11
North, Thomas B. "Liquid Nitrogen Propulsion Systems for Automotive Applications: Calculation of Mechanical Efficiency of a Dual, Double-acting Piston Propulsion System." Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc6070/.
Full textAbstract:
A dual, double-acting propulsion system is analyzed to determine how efficiently it can convert the potential energy available from liquid nitrogen into useful work. The two double-acting pistons (high- and low-pressure) were analyzed by using a Matlab-Simulink computer simulation to determine their respective mechanical efficiencies. The flow circuit for the entire system was analyzed by using flow circuit analysis software to determine pressure losses throughout the system at the required mass flow rates. The results of the piston simulation indicate that the two pistons analyzed are very efficient at transferring energy into useful work. The flow circuit analysis shows that the system can adequately maintain the mass flow rate requirements of the pistons but also identifies components that have a significant impact on the performance of the system. The results of the analysis indicate that the nitrogen propulsion system meets the intended goals of its designers.
12
Stanko, Mark Thomas. "An evaluation of marine propulsion engines for several Navy ships." Thesis, Cambridge, Massachusetts : Massachusetts Institute of Technology, 1992. http://handle.dtic.mil/100.2/ADA254871.
Full textAbstract:
Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1992 and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1992.Thesis Advisors: Wilson, D. G. ; Carmichael, A. Douglas. "May 1992." Description based on title screen as viewed on March 30, 2009 Includes bibliographical references (p. 57-58). Also available in print.
13
Pêgo, João Pedro Gomes Moreira. "Advanced fluid mechanics studies of ship propulsion systems." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=983754853.
Full text
14
Ballard, Michael A. "Impacts of electric propulsion systems on submarine design." Thesis, Springfield, Va. : Available from the National Technical Information Service, 1989. http://handle.dtic.mil/100.2/ADA213542.
Full textAbstract:
Thesis (Degree of Naval Engineer and M.S. in Electrical Engineering and Computer Science) Massachusetts Institute of Technology, June 1989.Includes bibliographical references. Also available online.
15
Wilhite, Jarred M. "Investigation of Various Novel Air-Breathing Propulsion Systems." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin147981623341895.
Full text
16
Neumann, Patrick Reinhard Christian. "Centre-Triggered Pulsed Cathodic Arc Spacecraft Propulsion Systems." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/13810.
Full textAbstract:
Satellites must carry some manner of propulsion system so that course correction or orbit stationkeeping manoeuvres can be carried out. Chemical thrusters have lower specific impulse than electric propulsion systems, and so focus has turned to using plasma and ion propulsion systems such as Hall Effect thrusters and gridded ion thrusters. Both of these systems use gaseous propellants and require a charge neutralisation system, both of which impose certain design compromises. This thesis explores the potential use of pulsed cathodic arcs as a spacecraft propulsion system, determining fuel specific impulse and jet power efficiency of a range of suitable materials over a range of arc currents and pulse durations. Comparisons between element classes are made, so as to identify candidate materials for various mission profiles. The results for magnesium in particular stand out as being comparable to several thruster technologies that are flight-rated.
17
Cheney, Liam Jon. "Development of Safety Standards for CubeSat Propulsion Systems." DigitalCommons@CalPoly, 2014. https://digitalcommons.calpoly.edu/theses/1180.
Full textAbstract:
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.
18
Mantellato, Riccardo. "Investigation of Deorbiting Systems using Passive Electrodynamic Propulsion." Doctoral thesis, Università degli studi di Padova, 2015. http://hdl.handle.net/11577/3424284.
Full textAbstract:
In the last decade, the continuous and alarming growth of space debris prompted many space agencies all over the world to adopt debris mitigation strategies. Present guidelines indicate the need to deorbit new satellites launched into low Earth orbit (LEO) within 25 years from their end of life. At present, a space-proven technology suitable to carry out a complete deorbit utilizes classical chemical propulsion. However, a deorbit
maneuver by means of chemical rocket strongly affects the satellite propulsion budget, thus limiting the operational life of the satellite. These issues bring the need to develop innovative deorbiting technologies. One of these consists in using electrodynamic tethers that, through its interaction with the Earth ionosphere and magnetic field, can take advantage of Lorentz forces for deorbiting. Previous studies have shown the effectiveness of such a technology to deorbit LEO satellites from different altitudes and inclinations in a relatively short time. This work addresses some of the issues of deorbit systems based on electrodynamic tether systems. First, a passive elastic-viscous damping device installed at the attachment point of the tether to the spacecraft is studied to damp the low and yet continuous injection of energy into the system produced by
Lorentz forces that, in the long run, can bring the tether to instability. Second, the issues related to the in-orbit deployment of a tape-shaped tether from a non-tumbling spacecraft are attacked to find simple and
effective solutions. The chosen strategy is to deploy a tethered tip mass following a pre-determined flight path fed forward to a linear proportional-derivative closed-loop control operated by a brake system mounted on
the deployer reel. Lastly, an optimization process for bare electrodynamic tether systems has been developed. The analysis focuses on the deorbiting performances of electrodynamic tether systems from LEO high ranking hot spot regions (e.g., sun-synchronous orbits), and includes a realistic mass budget of a deorbiting system suitable for small satellites.La continua ed allarmante crescita del numero di detriti spaziali avvenuta negli ultimi dieci anni ha spinto le agenzie spaziali di tutto il mondo ad adottare specifiche strategie di mitigazione. Le attuali linee guida internazionali indicano la necessità di far deorbitare i nuovi satelliti lanciati in orbita terrestre bassa (LEO) entro 25 anni dalla fine della loro vita operativa. Attualmente, i sistemi basati sulla propulsione chimica costituiscono l'unica tecnologia spaziale collaudata adatta ad effettuare un deorbiting completo di un satellite. Tuttavia, l'utilizzo di razzi per una manovra deorbitante richiede un considerevole quantitativo di propellente, andando ad influenzare fortemente il budget di massa del satellite, limitandone così la vita operativa. Ciò porta alla necessità di sviluppare tecnologie innovative per il rientro a fine vita di satelliti. Una di queste consiste nell'utilizzo di fili elettrodinamici che, attraverso l'interazione con la ionosfera e il campo magnetico terrestre, sfruttano le forze di Lorentz per effettuare il rientro. Studi precedenti hanno dimostrato l'efficacia di tale tecnologia per il deorbiting di satellite in LEO da diverse altezze e inclinazioni orbitali in un tempo relativamente breve. Questo lavoro di tesi affronta alcuni dei problemi caratteristici dei sistemi di deorbiting basati su sistemi a filo elettrodinamico. Innanzitutto, è stato studiato l'impiego di un sistema viscoelastico passivo da installare in corrisponenza dell'interfaccia tra filo e satellite. Questo sistema è stato ideato per smorzare il flusso di energia prodotto dalle forze di Lorentz che continuamente entra nel sistema e che, a lungo andare, può portare il tether all'instabilità dinamica. In secondo luogo, si è affrontato il problema relativo al dispiegamento in orbita di un filo a forma di nastro (tape tethers) da un veicolo spaziale il cui assetto è noto. La strategia scelta è quella di dispiegare dal satellite-base un sub-satellite seguendo una traiettoria predefinita, facendo uso di un sistema di controllo in retroazione lineare proporzionale-derivativo operato da un impianto frenante montato sull'albero del sottosistema di dispiegamento. Infine, è stato sviluppato un processo di ottimizzazione per sistemi a filo elettrodinamico. L'analisi si concentra sulle prestazioni dei sistemi elettrodinamici per il deorbiting di satelliti di piccola taglia (Small Satellites) da orbite LEO appartenenti a regioni sensibili (ad esempio, le orbite polari eliosincrone). Il processo di ottimizzazione è anche in grado di fornire un mass budget realistico del sistema di rientro.
19
Moretto, Federico. "Performance Characterization of Propulsion Systems for Spacecraft Applications." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3427546.
Full textAbstract:
The subject of the research program described in the present work is the analysis of hybrid rocket motors performance, through different experimental campaigns, which have been conducted on both small scale and full scale versions. The diagnostics system was composed by sensors to measure the pressure levels in many different sections of the propulsion system, sensors to monitor the burned quantity of fuel and oxidizer and sensors useful to define the physical conditions of the used oxidant: liquid nitrous oxide, in auto-pressurization form.
During this experience with chemical propulsion systems at CISAS, various test types have been performed, in order to study all the problematics, which concern the functioning of a hybrid rocket: a) discharge tests, to set-up the hydraulic circuit,
valve actuation and injection of oxidizer; b) ignition tests, to understand the issues that are connected with the initial burning phases; c) hot firing tests, to investigate the behavior of the motor during complete functioning operations.
All the needed instrumentation has been accurately and specifically designed and produced for this scope: the experimental facilities, the test bench, the different versions of the motor subsystems. A huge amount of work has been done, and it has permitted to verify the effect of many different design solutions on the final performance of the tested rockets.
An initial small scale experimental campaign served as a “test bench” in order to preliminarily verify main issues in the development of chemical propulsion systems, to calibrate the diagnostics and to highlight the initial performance characteristics
of the motor: in particular, the final choice of the fuel grain material has been done in this phase. After that, a first full scale motor version has been designed, using the resulting data of the small scale tests: the analysis on the verified instabilities started from this experimental campaign, in which an unstable behavior has been investigated and assigned to the injection of oxidizer in combustion chamber. For this reason, an accurate research program has been set-up to deep analyse how the fluid enters and behaves prior and after the injection plate: in a dedicated facility, many different injector types have been tested in different discharge conditions, in order to investigate the physical properties of N2O in auto-pressurization form, as it is used in the tested motors. The results of this intermediate program have permitted to upgrade some technical solutions of the rocket design, and improve its performance both in terms of combustion efficiency and instabilities mitigation.
To check the effects on the developed performance, two final verification test campaigns have been carried out, on two different motor versions. This has been useful also in the developing of a real “proto-flight” motor, which adopted lightweight materials and compact configurations: the experimental campaigns have been very useful in the definition of all the stresses, that would affect a possible payload of the produced propulsion system.Oggetto del programma di ricerca è l’analisi delle prestazioni di propulsori ibridi attraverso campagne sperimentali condotte su motori in scala ridotta e completa. Le misure effettuate sono state acquisite attraverso un apposito sistema di diagnostica, composto da sensori per la misura dei valori di pressione in differenti sezioni del sistema propulsivo, sensori per il monitoraggio delle quantità impiegate di combustibile e comburente, e sensori per definire le condizioni fisiche dell’ossidante: protossido d’azoto auto-pressurizzato. Durante questa esperienza condotta al CISAS nell’ambito della propulsione chimica, svariate prove sperimentali sono state condotte per studiare le problematiche che concernono il funzionamento di motori ibridi: a) test di scarica ossidante, per la messa a punto del circuito idraulico, del funzionamento della valvola principale e delle prestazioni del sistema di iniezione; b) test di accensione, per investigare le problematiche connesse con le fasi iniziali della combustione; c) test a fuoco, per lo studio del motore durante il completo funzionamento. Tutta la strumentazione necessaria è stata accuratamente progettata e prodotta con tali finalità: la facility sperimentale, il banco di test e le diverse versioni dei sottosistemi del motore. Una consistente mole di lavoro è stata portata a termine, e ha permesso la verifica degli effetti di diverse soluzioni progettuali sulle prestazioni finali sviluppate dagli endoreattori testati. Una prima campagna sperimentale su motori in scala ridotta ha servito come “banco prova” per prendere confidenza con i sistemi propulsivi chimici, per la calibrazione della diagnostica e per evidenziare le iniziali caratteristiche prestazionali: in particolare, in questa fase è stata fatta la scelta definitiva del materiale per il grano combustibile. In un secondo momento, una prima versione in scala completa del motore è stata progettata, impiegando i risultati della precedente campagna sul propulsore in scala ridotta: l’analisi delle instabilità di combustione è iniziata a partire da questa serie di test, nella quale il comportamento instabile è stato studiato e riconosciuto come effetto dell’iniezione di ossidante nella camera di combustione. Per questo motivo, una precisa fase di studio è stata implementata per analizzare come il fluido si comporta a cavallo della piastra di iniezione: attraverso un set-up sperimentale dedicato, svariati tipi di iniettore sono stati testati in molte configurazioni diverse, nell’ottica di studiare attentamente le proprietà fisiche dell’N2O in condizione auto-pressurizzata, così come è stato impiegato nei test del motore. I risultati di questa fase intermedia hanno permesso di aggiornare alcune soluzioni tecniche del design del motore, e migliorarne in questo modo le prestazioni sia in termini di efficienza di combustione, sia nell’attenuazione delle instabilità. La verifica degli effetti sulle prestazioni sviluppate è stata effettuata durante due ultime campagne di test, condotte su due diverse versioni del motore. L’utilità di questo lavoro è stato anche quello di sviluppare una realistica versione “pre-volo” del motore, che ha impiegato materiali leggeri e una configurazione compatta: le campagne sperimentali sono state molto utili nella definizione delle sollecitazioni che potrebbero interessare un eventuale payload del sistema propulsivo prodotto.
20
FLORIS, ANDREA. "Design of systems and components for high-speed electric propulsion systems." Doctoral thesis, Università degli Studi di Cagliari, 2020. http://hdl.handle.net/11584/284404.
Full textAbstract:
This PhD dissertation presents the modelling and design of a novel High Speed (HS) Electric Propulsion System (EPS) for automotive application. In particular, Chapter I presents a comparison among different EPS configurations, which are designed by combining different Permanent Magnet Synchronous Machines (PMSMs) with the corresponding most suitable transmission system; this is done in order to investigate the competitiveness of HS-EPS for automotive applications.
Subsequently, the design of a novel ferrite-based HS-PMSM suitable for automotive application is presented in Chapter II. The design has been carried out through a novel multi-parameter analytical design procedure, which has been developed with the aim of achieving a preliminary machine design that considers both design targets and constraints. This preliminary design has been then validated through accurate and extensive finite element analyses, which regard both mechanical and electromagnetic performances.
In order to guarantee appropriate coupling between the designed HS-PMSM and vehicle wheels, the design and optimization of a novel coaxial Magnetic Gear Transmission (MaGT) is presented in Chapter III. In particular, a single-stage MaGT is designed at first in accordance with mechanical and magnetic analytical models. However, as far as a very high gear ratio is required (more than 20), the design of a double-stage MaGT has been carried out, which addresses some of the issues arising from the single-stage solution. A comparison in terms of performances and sizes between the two designed MaGTs is thus presented and discussed: the results obtained through the analytical models are validated by means of accurate finite element analyses. Subsequently, a further optimization of the double-stage MaGT has been carried out, which aims at reducing the harmonic content of the magnetic flux density. A comparative study between the two double stage MaGTs is presented and discussed, especially with reference to core losses and temperature distribution, highlighting the improved performances achieved by the optimized configuration.
21
Curreli, Davide. "Analysis, simulation and testing of advanced electrodynamic systems for space propulsion." Doctoral thesis, Università degli studi di Padova, 2011. http://hdl.handle.net/11577/3421628.
Full textAbstract:
Helicon plasma sources are an attractive means of plasma production in advanced applications of space propulsion thanks to their high ionization efficiency. By means of a compact helicon source, it is possible to enhance the performances of a small propulsive apparatus from a range of almost negligible values (few micro-Newton of thrust and few tens of seconds of specific impulse) to a range useful for many applications (thrust of milli-Newton and 1000s seconds of specific impulse). However, the design of such a system is complicated by the great inter-correlations between the involved parameters, and by the complex physical mechanisms involved. Moreover, thruster operation involve physical regimes which are not common in industrial plasma sources. In this research program, helicon physics has been deeply analyzed in a innovative way, not limiting the study to helicon wave analysis with dielctric tensors, but recognizing that the electromagnetic wave propagation must be closely related to macroscopic transport. An equilibrium theory of an helicon discharge has been derived, where both the plasma-wave local coupling of the RF antenna field with the plasma, and the transport of plasma species at the macroscopic level, are considered. The theory has been practically implemented on a code and validated with experiments in Laboratory. The theory has allowed to close the correlations between the design parameters and to identify preliminary design configurations of helicon thrusters.Grazie alla loro elevata efficienza, le sorgenti al plasma di tipo helicon sono un attraente mezzo di produzione di plasma per applicazioni avanzate di propulsione spaziale. Per mezzo di una compatta sorgente helicon, è possibile incrementare le prestazioni di un piccolo apparato propulsivo, da un range di valori pressoché trascurabili (pochi micro-Newton di spinta e qualche decina di secondi di impulso specifico) ad un range utile per molte applicazioni (spinta del milli-Newton e migliaia di secondi di impulso specifico). Tuttavia il design di un tale sistema è complicato dalla grande inter-correlazione tra i parametri coinvolti, e dai complessi meccanismi fisici coinvolti. Inoltre il regime operativo del thruster avviene in regimi fisici non comuni per plasmi di sorgenti industriali. In questo programma di ricerca la fisica fondamentale degli helicon è stata attentamente studiata, non limitando le analisi al problema di accoppiamento d'onda con tensore dielettrico, ma riconoscendo che il problema elettromagnetico è strettamente connesso al traporto macroscopico. E' stata sviluppata una teoria dell'equilibrio di una scarica helicon, dove sono tenuti in considerazione sia l'accoppiamento locale plasma-onda del campo RF (radiofrequenza) dell'antenna con il plasma, che il trasporto delle specie di plasma a livello macroscopico. La teoria è stata implementata in un codice e validata con esperimenti in Laboratorio. La teoria ha permesso di chiudere le correlazioni fra i parametri di design e di identificare delle configurazioni preliminari di propulsori helicon.
22
North, Thomas B. Plummer Mitty Charles. "Liquid nitrogen propulsion systems for automotive applications calculation of the mechanical efficiency of a dual, double-acting piston propulsion system /." [Denton, Tex.] : University of North Texas, 2008. http://digital.library.unt.edu/permalink/meta-dc-6070.
Full text
23
Meadowcroft, Brian K. "Hidden Failures in Shipboard Electrical Integrated Propulsion Plants." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/42754.
Full textAbstract:
The differences between shipboard and land based power systems are explored to support the main focus of this work. A model was developed for simulating hidden failures on shipboard integrated propulsion plants, IPP. The model was then used to evaluate the segregation of the IPP high voltage, HV, buses in a similar fashion as a shipboard firemain. The HV buses were segregated when loss of propulsion power would put the ship as risk. This new treatment reduces the region of vulnerability by providing a high impedance boundary that limits the effects of a hidden failure of a current magnitude or differential based protective element, without the installation of any additional hardware or software. It is shown that this protection could be further improved through the use of a simple adaptive protection scheme that disarms unneeded protective elements in certain configurations.Master of Science
24
Henshall, P. R. "Applications of fibre optics in solar thermal propulsion systems." Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/843528/.
Full textAbstract:
Solar thermal propulsion (STP) is the utilisation of concentrated sunlight for heating a propellant to high temperatures. Early STP concepts were envisioned for large spacecraft and capable of high levels of propulsive performance (< 1000s Isp). Currently, at the University of Surrey, STP is being adapted for use on small-spacecraft in order to utilise the high propulsive capability offered by STP and widen the range of small-spacecraft applications. Conventional STP system concepts encounter difficulties in conforming to the low mass and volume requirements of a small- spacecraft platform. An enabling technology for the miniaturisation of an STP system is seen in the advent of low attenuation high numerical aperture (NA) fibre optics. This work investigates the mission and design implications of an STP system augmented with fibre optics and develops new technologies that stem from the concept. A small parabolic dish concentrator was designed to the requirements of a high NA optical fibre and manufactured for component testing. Efficiency tests of the small concentrator demonstrated 83% efficiency and an overall system efficiency of 50% including coupling light into the fibre. A fibre optic heat exchanger was designed, manufactured and tested to investigate methods of improving heat transfer efficiency. Tests of the heat exchanger demonstrated receiver absorption efficiencies of 82%. Stringent solar pointing accuracies imposed by the small concentrator-fibre optic combination resulted in the development and testing of a novel sensor technology that employs fibre optic luminescence as feedback for a concentrator pointing control mechanism. Concentrator pointing accuracies of 3 arc-minutes were experimentally demonstrated. Accompanying this work is the development of a novel algorithm for the study of coupled radiation and conduction heat transfer within participating media, which is more accurate and stable than conventional techniques. This work successfully demonstrated the potential high efficiency and feasibility of a small- spacecraft fibre augmented STP system.
25
Aleid, Louay. "Variable cycle propulsion systems for a supersonic civil transport." Thesis, Cranfield University, 1997. http://hdl.handle.net/1826/4433.
Full textAbstract:
The different aspects of overall performance of three variable cycle engines
(VCE) candidates for future supersonic civil transport are analysed in this work. These
aspects concern the design and off-design points performance, the airframe engine
integration and variable geometry compressor and turbine design and performance.
The three engines are compared to a traditional turbojet. The variable
compressor maps were obtained with their running lines for the whole mission profile
including the transition mode from medium býpass ratio to a lower bypass ratio turbofan.
The specific fuel consumption (SFC) of the VCEs showed a significant improvement,
especially at subsonic cruise, relative to a Turbojet engine. The extent of the variable
geometry on the compressor stator angles, mixing area and the nozzle throat and exit
areas is evaluated. The Fuel bill is estimated for two standard mission profiles.
The effect of installation is estimated on an isolated nacelle. A sizing calculation
is carried out for the whole nacelle including the intake and the nozzle. The drag due to
the friction, pre-entry, afterbody and the shock waves is calculated in order to estimated
the installed performance of the three engines.
In the search of improving the VCE performance at subsonic cruise, the use of
variable geometry at the low pressure turbine for the Turbofan-Turbojet engine is
investigated. The effects of varying the LP turbine guide vanes stagger angle on the
engine performance and component parameters are analysed. The turbine efficiency and
non-dimensional mass flow changes due to the use of variable geometry are estimated.
An updated version of the Turbornatch program was corrected and tested in
order to study variable cycle engines, especially to simulate the transition from one mode
to another.
26
Celis, Cesar. "Evaluation and optimisation of environmentally friendly aircraft propulsion systems." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4686.
Full textAbstract:
In this globalised world where the efficient transportation of people and goods
greatly contributes to the development of a given region or country, the aviation
industry has found the ideal conditions for its development, thereby becoming in one of
the fastest growing economic sectors during the last decades. The continuing growth in
air traffic and the increasing public awareness about the anthropogenic contribution to
global warming have meant that environmental issues associated with aircraft
operations are currently one of the most critical aspects of commercial aviation. Several
alternatives for reducing the environmental impact of aircraft operations have been
proposed over the years, and they broadly comprise reductions in the number of aircraft
operations, changes in the type of aircraft, and changes in the aircraft operational rules
and procedures. However, since the passenger traffic is expected to increase over the
next years, only the last two options seem to be the most feasible solutions to alleviate
the problem. Accordingly, the general aim of this research work is to develop a
methodology to evaluate and quantify aircraft/engines design trade-offs originated as a
consequence of addressing conflicting objectives such as low environmental impact and
low operating costs. More specifically, it is an objective of this work to evaluate and
optimise both aircraft flight trajectories and aircraft engine cycles taking into account
multidisciplinary aspects such as performance, gaseous emissions, and economics.
In order to accomplish the objectives proposed in this project, a methodology for
optimising aircraft trajectories has been initially devised. A suitable optimiser with a
library of optimisation algorithms, Polyphemus, has been then developed and/or
adapted. Computational models simulating different disciplines such as aircraft
performance, engine performance, and pollutants formation, have been selected or
developed as necessary. Finally, several evaluation and optimisation processes aiming
to determine optimum and ‘greener’ aircraft trajectories and engine cycles have been
carried out and their main results summarised. In particular, an advanced, innovative
gaseous emissions prediction model that allows the reliable calculation of emissions trends from current and potential future aircraft gas turbine combustors has been
developed. When applied to a conventional combustor, the results showed that in
general the emission trends observed in practice were sufficiently well reproduced, and
in a computationally efficient manner for its subsequent incorporation in optimisation
processes. For performing the processes of optimisation of aircraft trajectories and
engine cycles, an optimiser (Polyphemus) has also been developed and/or adapted in
this work. Generally the results obtained using Polyphemus and other commercially
available optimisation algorithms presented a satisfactory level of agreement (average
discrepancies of about 2%). It is then concluded that the development of Polyphemus is
proceeding in the correct direction and should continue in order to improve its
capabilities for identifying and efficiently computing optimum and ‘greener’ aircraft
trajectories and engine cycles, which help to minimise the environmental impact of
commercial aircraft operations.
The main contributions of this work to knowledge broadly comprise the
following: (i) development of an environmental-based methodology for carrying out
both aircraft trajectory optimisation processes, and engine cycle optimisation-type ones;
(ii) development of both an advanced, innovative gas turbine emissions prediction
model, and an optimiser (Polyphemus) suitable to be integrated into multi-disciplinary
optimisation frameworks; and (iii) determination and assessment of optimum and
‘greener’ aircraft trajectories and aircraft engine cycles using a multi-disciplinary
optimisation tool, which included the computational tools developed in this work. Based
on the results obtained from the different evaluation and optimisation processes carried
out in this research project, it is concluded that there is indeed a feasible route to reduce
the environmental impact of commercial aviation through the introduction of changes in
the aircraft operational rules and procedures and/or in the aircraft/engine configurations.
The magnitude of these reductions needs to be determined yet through careful
consideration of more realistic aircraft trajectories and the use of higher fidelity
computational models. For this purpose, the computations will eventually need to be
extended to the entire fleet of aircraft, and they will also need to include different
operational scenarios involving partial replacements of old aircraft with new
environmentally friendly ones.
27
Leonessa, Alexander. "Hierarchical robust nonlinear switching control design for propulsion systems." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/11997.
Full text
28
Hughes, Adam William. "Investigation of tip-driven thruster and waterjet propulsion systems." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322015.
Full text
29
Fallows, Christopher David. "Characterisation of the propulsion systems of autonomous underwater vehicles." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420187.
Full text
30
Thomson, J. Ben (Jules Ben). "Acoustically optimized propulsion systems using a Cause-Effect Controller." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/113750.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Thesis: S.M. in Naval Architecture and Marine Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 239-240).
The proposed Acoustic Response Control Process (ARCP) allows for a "Cause- Effect" Controller (CEC) to provide a method to optimize the trade-off between a marine vessel's ability to maneuver and the radiated acoustic noise (or internal vibrations). Through the discretization of both a marine vessel's motion and all possible configurations for the vessel's propulsion and control systems, a finite number of unique states can be created. The ARCP uses hardware and software together with a CEC to learn the cause-and-effect relationship between the finite states of the ship and the resulting acoustic noise and vibrations which are generated. Once this relationship is determined, the same CEC can use these relationships in reverse order to predict the amount of acoustic noise that would be generated by a proposed propulsion change or maneuver. In this context, any maneuver or speed change is simply considered a state change. The CEC could then choose the optimal new end state, along with intermediate states which provides the greatest speed, acceleration, and ability to maneuver without exceeding the user-defined acoustic thresholds. The ARCP offers a number of both civilian and military applications. The ARCP, for instance, can be used on merchant ships to avoid certain frequency and amplitude combinations which interfere with marine life. Vehicles that use acoustic sensors could optimize their search speeds while minimizing their own noise which interferes with their sensors. For military applications, the ARCP will give vessels the greatest ability to maneuver while maintaining stealth from hostile acoustic sensors.
by J. Ben Thomson.
S.M.
S.M. in Naval Architecture and Marine Engineering
31
Getty, Daniel (Daniel E. ). "Testing new potential fuels for ion electrospray propulsion systems." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120433.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 73-75).
Electrospray thrusters are a class of electric propulsion that extract and accelerate ions from the surface of an electrically conductive liquid surface. This liquid surface is that of an ionic liquid, a room temperature molten salt, applied to a porous substrate. The substrate is etched via laser to form a field enhancing structure off of which ions will be evaporated. This research expands on the field in two separate ways. First, it implements and evaluates a carbon xerogel emitter substrate as an alternative over current glass emitters. This substrate was found to fire stably and with higher stable currents than the glass alternative (1.5 - 2 times the maximum stable current). In addition, this work analyzes and evaluates two new high conductivity ionic liquid propellants, EMI-(HF)F and S111-(HF)F. Improvements or disadvantages of EMI- (HF)F over the current baseline of EMI-CF₃BF₃ were inconclusive. S111-(HF)F, however, showed a distinct improvement in specific impulse over EMI-CF₃BF₃ (3160 ± 290 s vs. 2140 ± 130 s) without a statistically significant drop in total efficiency. Future work could include the collection of time of flight data in the negative firing mode, as well as higher precision retarding potential data in both positive and negative polarities. Additional measures could also be taken to decrease the spacing between emitter tips on the carbon substrate, thereby increasing the current and thrust density of the thrusters.
by Daniel Getty.
S.M.
32
Patel, Bhavesh T. (Bhavesh Tribbovan). "Systems analysis of an astrophysics mission utilizing electric propulsion." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/46449.
Full text
33
Peters, Andreas Ph D. Massachusetts Institute of Technology. "Assessment of propfan propulsion systems for reduced environmental impact." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58080.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 135-138).
Current aircraft engine designs tend towards higher bypass ratio, low-speed fan designs for improved fuel burn, reduced emissions and noise. Alternative propulsion concepts include counter-rotating propfans (CRPs) which have been investigated intensively in the 1970s and 1980s and demonstrated significant reductions in fuel burn. Currently, propfans are being studied again due to their inherent noise challenge and the potential for reduced environmental impact. A newly developed, integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations is introduced. The approach is based on first principles and combines a coupled aircraft and propulsion system performance analysis with 3-D unsteady, full-wheel CRP CFD computations and aero-acoustic simulations. Special emphasis is put on computing CRP interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance and mission analysis was first conducted on a candidate CRP powered configuration. In addition, a comparable aircraft with advanced turbofan engines was defined for performance and noise comparisons.
(cont.) Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out using vortex-lattice methods and 3-D steady RANS computations of the counter-rotating stage. Full-wheel unsteady 3-D RANS simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein's formulation of the acoustic analogy for moving media and Hanson's single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to experimental data and demonstrated good agreement between the computed and measured interaction tones. The underlying noise source mechanisms due to front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows and front-rotor tip vortices were dissected and quantified. Based on this investigation, the CRP was re-designed for reduced noise incorporating a clipped rear-rotor and an increased rotor-rotor spacing to reduce upstream influence, tip vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the re-designed CRP exhibited an average reduction of 7.25 dB in mean SPL computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the re-designed CRP demonstrated a reduction of 9.2 EPNdB and 8.6 EPNdB at the FAR 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements.
by Andreas Peters.
S.M.
34
Najafi, Saatlou Esmail. "Techno-economic environmental assessment of advanced intercooled propulsion systems." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/9600.
Full textAbstract:
A tool based on a Techno-economic and Environmental Risk Assessment (TERA)
framework is useful at the preliminary stage of an aero engine design process, to
conceive and assess engines with minimum environmental impact and lowest cost of
ownership, in a variety of emission legislation and taxation policy scenarios.
This research was performed as part of the EU FP6 New Aero engine Core concepts
(NEWAC) programme which was established to assess the potential of innovative gas
turbine core technologies to enhance thermal efficiency thereby reducing CO2
emissions and fuel consumption. A representative prediction of engine life and mission
fuel burn at the earliest possible design stage is a crucial task that can provide an
indication of the approximate overall engine direct operating costs. Two aero engines,
a conventional turbofan and a conceptual intercooled turbofan, were assessed and
optimised using the TERA approach to identify the designs that provided the maximum
time between overhaul (and therefore the minimum maintenance costs). In order to
perform these assessments (which included sensitivity and parametric analyses, and
optimisation studies) several models were developed and integrated in an optimisation
framework. A substantial effort was devoted to the development of a detailed lifing
model that calculates the engine life with a reasonable level of accuracy by integrating
physics based oxidation, creep and fatigue models.
The results obtained from the study demonstrate that an engine optimised for
maximum time between overhaul requires a lower overall pressure ratio and specific
thrust but this comes at the cost of lower thermal efficiency and therefore higher
mission fuel burn.
The main contribution to knowledge of this work is a multidisciplinary TERA
assessment of a novel intercooled conceptual aero engine. Particular emphasis is
placed on the design space exploration and optimisation studies to identify the designs
that may offer the largest time between overhaul. The consequent implications
therefore this may have on mission fuel burn and direct operating costs.
In addition to refining the various TERA models, one of the main recommendations for
further work is to optimise the engines for minimum direct operating cost to identify the
best economic compromise between engine life and mission fuel burn. This can be
done by considering different fuel prices and under a variety of hypothetical emission
taxation scenarios, to identify the circumstances in which intercooled engine
technology may become economically viable.
35
Shah, Parthiv N. "Novel turbomachinery concepts for highly integrated airframe/propulsion systems." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/38929.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 251-260).
Two novel turbomachinery concepts are presented as enablers to advanced flight missions requiring integrated airframe/propulsion systems. The first concept is motivated by thermal management challenges in low-to-high Mach number (4+) aircraft. The idea of compressor cooling combines the compressor and heat exchanger function to stretch turbopropulsion system operational limits. Axial compressor performance with blade passage heat extraction is assessed with computational experiments and meanline modeling. A cooled multistage compressor with adiabatic design point is found to achieve higher pressure ratio, choking mass flow, and efficiency (referenced to an adiabatic, reversible process) at fixed corrected speed, with greatest benefit occurring through front-stage cooling. Heat removal equal to one percent of inlet stagnation enthalpy flux in each of the first four blade rows suggests pressure ratio, efficiency, and choked flow improvements of 23%, 12%, and 5% relative to a baseline, eight-stage compressor with pressure ratio of 5. Cooling is also found to unchoke rear stages at low corrected speed. Heat transfer estimations indicate that surface area limitations and temperature differences favor rear-stage cooling and suggest the existence of an optimal cooling distribution.
(cont.) The second concept is a quiet drag device to enable slow and steep approach profiles for functionally quiet civil aircraft. Deployment of such devices in clean airframe configuration reduces aircraft source noise and noise propagation to the ground. The generation of swirling outflow from a duct, such as an aircraft engine, is conceived to have high drag and low noise. The simplest configuration is a ram pressure driven duct with non-rotating swirl vanes, a so-called swirl tube. A device aerodynamic design is performed using first principles and CFD. The swirl-drag-noise relationship is quantified through scale-model aerodynamic and aeroacoustic wind tunnel tests. The maximum measured stable flow drag coefficient is 0.83 at exit swirl angles close to 500. The acoustic signature, extrapolated to full-scale, is found to be well below the background noise of a well populated area, demonstrating swirl tube conceptual feasibility. Vortex breakdown is found to be the aerodynamically and acoustically limiting physical phenomenon, generating a white-noise signature that is [approx.] 15 dB louder than a stable swirling flow.
by Parthiv Narendra Shah.
Ph.D.
36
Scrignoli, Francesco <1991>. "Optimization and development of low environmental impact propulsion systems." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10189/1/PhD_thesis.pdf.
Full textAbstract:
The aim of the Ph.D. research project was to explore Dual Fuel combustion and hybridization. Natural gas-diesel Dual Fuel combustion was experimentally investigated on a 4-Stroke, 2.8 L, turbocharged, light-duty Diesel engine, considering four operating points in the range between low to medium-high loads at 3000 rpm. Then, a numerical analysis was carried out using a customized version of the KIVA-3V code, in order to optimize the diesel injection strategy of the highest investigated load. A second KIVA-3V model was used to analyse the interchangeability between natural gas and biogas on an intermediate operating point. Since natural gas-diesel Dual Fuel combustion suffers from poor combustion efficiency at low loads, the effects of hydrogen enriched natural gas on Dual Fuel combustion were investigated using a validated Ansys Forte model, followed by an optimization of the diesel injection strategy and a sensitivity analysis to the swirl ratio, on the lowest investigated load. Since one of the main issues of Low Temperature Combustion engines is the low power density, 2-Stroke engines, thanks to the double frequency compared to 4-Stroke engines, may be more suitable to operate in Dual Fuel mode. Therefore, the application of gasoline-diesel Dual Fuel combustion to a modern 2-Stroke Diesel engine was analysed, starting from the investigation of gasoline injection and mixture formation. As far as hybridization is concerned, a MATLAB-Simulink model was built to compare a conventional (combustion) and a parallel-hybrid powertrain applied to a Formula SAE race car.
37
Brochard, Paul Eugene. "Analysis of simulation tools for the study of advanced marine power systems." Thesis, Monterey, Calif. : Naval Postgraduate School, 1992. http://handle.dtic.mil/100.2/ADA257338.
Full textAbstract:
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 1992.Thesis Advisor: Williams, Stephen M. "September 1992." Description based on title screen as viewed on March 10, 2009. Includes bibliographical references (p. 103-105). Also available in print.
38
Skulj, Dzenita, and Ajna Hodzic. "Data Driven Anomaly Control Detection for Railway Propulsion Control Systems." Thesis, Mälardalens högskola, Inbyggda system, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-48520.
Full textAbstract:
The popularity of railway transportation has been on the rise over the past decades, as it has been able to provide safe, reliable, and highly available service. The main challenge within this domain is to reduce the costs of preventive maintenance and improve operational efficiency. To tackle these challenges, one needs to investigate and provide new approaches to enable quick and timely data collection, transfer, and storage aiming at easier and faster analysis whenever needed. In this thesis, we aim at enabling the monitoring and analysis of collected signal data from a train propulsion system. The main idea is to monitor and analyze collected signal data gathered during the regular operation of the propulsion control unit or data recorded during the regular train tests in the real-time simulator. To do so, we have implemented a solution to enable train signal data collection and its storage into a .txt and .CSV file to be further analyzed in the edge node and in the future connected to the cloud for further analysis purposes. In our analysis, we focus on identifying signal anomalies and predicting potential failures using MathWorks tools. Two machine learning techniques, unsupervised and supervised learning, are implemented. Additionally, in this thesis, we have investigated ways of how data can be efficiently managed. We have also reviewed existing edge computing solutions and anomaly detection approaches using a survey as a suitable method to identify relevant works within the state of the art.RELIANCE
39
Kwon, Kybeom. "A novel numerical analysis of Hall Effect Thruster and its application in simultaneous design of thruster and optimal low-thrust trajectory." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34777.
Full textAbstract:
Hall Effect Thrusters (HETs) are a form of electric propulsion device which uses external electrical energy to produce thrust. When compared to various other electric propulsion devices, HETs are excellent candidates for future orbit transfer and interplanetary missions due to their relatively simple configuration, moderate thrust capability, higher thrust to power ratio, and lower thruster mass to power ratio. Due to the short history of HETs, the current design process of a new HET is a largely empirical and experimental science, and this has resulted in previous designs being developed in a narrow design space based on experimental data without systematic investigations of parameter correlations. In addition, current preliminary low-thrust trajectory optimizations, due to inherent difficulties in solution procedure, often assume constant or linear performances with available power in their applications of electric thrusters. The main obstacles come from the complex physics involved in HET technology and relatively small amounts of experimental data. Although physical theories and numerical simulations can provide a valuable tool for design space exploration at the inception of a new HET design and preliminary low-thrust trajectory optimization, the complex physics makes theoretical and numerical solutions difficult to obtain. Numerical implementations have been quite extensively conducted in the last two decades. An investigation of current methodologies reveals that to date, none provide a proper methodology for a new HET design at the conceptual design stage and the coupled low-thrust trajectory optimization. Thus, in the first half of this work, an efficient, robust, and self-consistent numerical method for the analysis of HETs is developed with a new approach. The key idea is to divide the analysis region into two regions in terms of electron dynamics based on physical intuition. Intensive validations are conducted for existing HETs from 1 kW to 50 kW classes. The second half of this work aims to construct a simultaneous design optimization environment though collaboration with experts in low-thrust trajectory optimization where a new HET and associated optimal low-thrust trajectory can be designed simultaneously. A demonstration for an orbit raising mission shows that the constructed simultaneous design optimization environment can be used effectively and synergistically for space missions involving HETs. It is expected that the present work will aid and ease the current expensive experimental HET design process and reduce preliminary space mission design cycles involving HETs.
40
Karunarathne, Lakmal. "An intelligent power management system for unmanned aerial vehicle propulsion applications." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8038.
Full textAbstract:
Electric powered Unmanned Aerial Vehicles (UAVs) have emerged as a promi- nent aviation concept due to the advantageous such as stealth operation and zero emission. In addition, fuel cell powered electric UAVs are more attrac- tive as a result of the long endurance capability of the propulsion system. This dissertation investigates novel power management architecture for fuel cell and battery powered unmanned aerial vehicle propulsion application. The research work focused on the development of a power management system to control the hybrid electric propulsion system whilst optimizing the fuel cell air supplying system performances. The multiple power sources hybridization is a control challenge associated with the power management decisions and their implementation in the power electronic interface. In most applications, the propulsion power distribu- tion is controlled by using the regulated power converting devices such as unidirectional and bidirectional converters. The amount of power shared with the each power source is depended on the power and energy capacities of the device. In this research, a power management system is developed for polymer exchange membrane fuel cell and Lithium-Ion battery based hybrid electric propulsion system for an UAV propulsion application. Ini- tially, the UAV propulsion power requirements during the take-off, climb, endurance, cruising and maximum velocity are determined. A power man- agement algorithm is developed based on the UAV propulsion power re- quirement and the battery power capacity. Three power states are intro- duced in the power management system called Start-up power state, High power state and Charging power state. The each power state consists of the power management sequences to distribute the load power between the battery and the fuel cell system. A power electronic interface is developed Electric powered Unmanned Aerial Vehicles (UAVs) have emerged as a promi- nent aviation concept due to the advantageous such as stealth operation and zero emission. In addition, fuel cell powered electric UAVs are more attrac- tive as a result of the long endurance capability of the propulsion system. This dissertation investigates novel power management architecture for fuel cell and battery powered unmanned aerial vehicle propulsion application. The research work focused on the development of a power management system to control the hybrid electric propulsion system whilst optimizing the fuel cell air supplying system performances. The multiple power sources hybridization is a control challenge associated with the power management decisions and their implementation in the power electronic interface. In most applications, the propulsion power distribu- tion is controlled by using the regulated power converting devices such as unidirectional and bidirectional converters. The amount of power shared with the each power source is depended on the power and energy capacities of the device. In this research, a power management system is developed for polymer exchange membrane fuel cell and Lithium-Ion battery based hybrid electric propulsion system for an UAV propulsion application. Ini- tially, the UAV propulsion power requirements during the take-off, climb, endurance, cruising and maximum velocity are determined. A power man- agement algorithm is developed based on the UAV propulsion power re- quirement and the battery power capacity. Three power states are intro- duced in the power management system called Start-up power state, High power state and Charging power state. The each power state consists of the power management sequences to distribute the load power between the battery and the fuel cell system. A power electronic interface is developed with a unidirectional converter and a bidirectional converter to integrate the fuel cell system and the battery into the propulsion motor drive. The main objective of the power management system is to obtain the controlled fuel cell current profile as a performance variable. The relationship between the fuel cell current and the fuel cell air supplying system compressor power is investigated and a referenced model is developed to obtain the optimum compressor power as a function of the fuel cell current. An adaptive controller is introduced to optimize the fuel cell air supplying system performances based on the referenced model. The adaptive neuro-fuzzy inference system based controller dynamically adapts the actual compressor operating power into the optimum value defined in the reference model. The online learning and training capabilities of the adaptive controller identify the nonlinear variations of the fuel cell current and generate a control signal for the compressor motor voltage to optimize the fuel cell air supplying system performances. The hybrid electric power system and the power management system were developed in real time environment and practical tests were conducted to validate the simulation results.
41
Ziemba, Timothy Martin. "Experimental investigation of the mini-magnetospheric plasma propulsion prototype /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/9962.
Full text
42
DellaFera, Andrew Brian. "Optimization of Hypersonic Airbreathing Propulsion Systems through Mixed Analysis Methods." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/95512.
Full textAbstract:
Accurate flow path modeling of scramjet engines is a key step in the development of an
airframe integrated engine for hypersonic vehicles. A scramjet system model architecture is
proposed and implemented using three different engine components: the isolator, combustor,
and nozzle. For each component a set of intensive properties are iterated to match prescribed
conditions, namely the mass flow. These low-fidelity one-dimensional models of hypersonic
propulsion systems are used in tandem with Sandia Labs' Dakota optimization toolbox with
the goal of accelerating the design and prototyping process. Simulations were created for the
various components of the propulsion system and tied together to provide information for the
entire flow-path of the engine given an inlet state. The isolator model incorporated methods
to compute the intensive properties such as temperature and pressure of the flow path
whether a shock-train exists internally as a dual-mode ramjet or if the engine is operating
as a pure scramjet with a shock free isolator. A Fanno flow-like model was implemented
to determine the friction losses in the isolator and a relation is iterated upon to determine
the strength and length of the shock train. Two combustor models were created, the first of
which uses equilibrium chemistry to estimate the state of the flow throughout the combustor
and nozzle. Going one step further, the second model uses a set of canonical reactors to
capture the non-equilibrium effects that may exist in the combustor/nozzle. The equilibrium
combustor model was created to provide faster calculations in early iterations, and the reactor
model was created to provide more realistic data despite its longer computational time. The
full engine model was then compared and validated with experimental data from a scramjet
combustor rig. The model is then paired with an optimization toolbox to yield a preliminary
engine design for a provided design space, using a finite element analysis to ensure a feasible
design. The implemented finite element analysis uses a coarse mesh with simple geometry
to reduce computational time while still yielding sufficiently accurate results. The results of
the optimization are then available as the starting point for higher fidelity analyses such as
2-D or 3-D computational fluid dynamics.Master of Science
Ramjets and scramjets are the key to sustained flight at speeds above five times the speed of sound. These propulsion systems pose a challenging simulation environment due to the wide range of flow seen by the system structure. A scramjet simulation model is formulated using a series of combustion models with the goal of accurately modelling the combustion processes throughout the engine. The combustor model is paired with an isolator model and the engine model is compared against previous studies. A structural analysis model is then paired with the engine simulation, and the combined model is used within an optimizer to find an optimum design.
43
Schömann, Joachim [Verfasser]. "Hybrid-Electric Propulsion Systems for Small Unmanned Aircraft / Joachim Schömann." München : Verlag Dr. Hut, 2014. http://d-nb.info/1063222060/34.
Full text
44
Birgersson, Victoria, and Maximillian Lundgren-Goodman. "Dark Ages Lunar Interferometer - Deployment Rover : Propulsion and Steering Systems." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28888.
Full textAbstract:
2030 NASA Jet Propulsion Laboratory will place an interferometer, which will workas a radio telescope, on the far side of the Moon. The interferometer uses thinpolyamide films as antennas, which are rolled out by a rover (an autonomousvehicle). The thesis covers concept generation of the propulsion and steering systemof the rover.The interferometer is to be placed on the far side of the Moon in order to ensure, asfar as possible, that it is not effected by radiation from Earth. The interferometerconsists of several polyamide films, approximately 100 meters long and one meterwide. The films are to be connected in the middle in order to form a star pattern offilm. Since the rover is to roll out these films on the surface of the Moon, it will driveback and forth to the lander to pick up the rolls. The focus in the project has been todevelop a reliable and stable system as possible so that the rover can accomplish itsmission without malfunctions. The purpose with the interferometer is to map thehydrogen gas clouds which were formed during universe’s youth (Platt, 2008).The outcome of this project is a concept indicating what the most optimal design ofwheel mount, of motor mount, of wheel and steering design may be in order to steerthe rover. The method to generate concepts used is known Fredy Olsson’s method.This is a method that has been developed at Lunds University and it has been widelyused in engineering education at Halmstad University.The four concepts developed and contributes to the whole concept for propulsion andsteering system of the rover. The four concepts developed are an all six steering, allof the six wheels can be controlled individually. Each wheel is split, or divided intwo. The motor is angle mounted and the wheel is semi-open with a slope that makesthe Moon dust fall out if it comes inside.Inspiration from previous rovers which are or have been on the Moon and Mars hasbeen useful in generating concepts. Previously used concepts are stable and reliable,which are important factors in this project. Previous theses have come to theconclusion that the chassis of the rover should be the one similar to the one used onMars Science Laboratory Curiosity and Mars Exploration Rover’s Spirit andOpportunity.The Halmstad University projects in collaboration with NASA began at HalmstadUniversity in 2013, and previous projects have developed the chassis, energy systemand the deployment mechanism of the rover. This year’s project takes intoconsideration the results from previous years since a concept of a complete roverultimately is going to be presented to NASA Jet Propulsion Laboratory.The thesis is done in collaboration with NASA Jet Propulsion Laboratory inCalifornia, USA. NASA Jet Propulsion Laboratory is the leading U.S. center forrobotic exploration of the solar system.NASA Jet Propulsion Laboratory ska 2030 placera en interferometer på månensbaksida, interferometern ska fungera som ett radioteleskop. Interferometern användersig av tunna polyamidfilmer som antenner. Dessa ska rullas ut på månens yta av enrover (ett obemannat fordon). Rapporten behandlar framtagning av koncept förstyrning och framdrivning av denna rover.Interferometern ska placeras på månens baksida för att man i så stor mån som möjligtvill undkomma strålningsstörningar från Jorden. Interferometern ska bestå av flertaletpolyamidfilmer, ca 100 meter långa och en meter breda. Filmerna skasammankopplas i en kontrollenhet som finns i mitten av det stjärnformade mönsterfilmerna läggs i. Då rovern ska placera ut dessa filmer på månens yta, ska den skaköra från och till landaren för att hämta upp rullarna. Fokus i projektet har varit attgöra ett så pålitligt stabilt system som möjligt för att rovern ska klara av att slutförasitt uppdrag utan driftstörningar. Med interferometern vill man sedan kartläggavätgasmoln som bildades i universums ungdom (Platt, 2008).Resultatet av projektet är ett koncept som visar roverns framdrivnings- ochstyrsystem, hjulupphängning, motorplacering samt hur hjuldesignen kan se ut. FredyOlssons metoder har använts för att ta fram koncept som uppfyller krav och önskemåldå denna metod har använts tidigare under utbildningen.De fyra koncept som bidrar till ett koncept för hela styr- och framdrivningssystem ärstyrning och framdrivning på roverns alla sex hjul, hjulen är designade på så vis att deär delade i två. Motorn är vinkelmonterad. Roverns hjul är semi-öppna med en kantsom är högre än det djup hjulet sjunker ner i månytan., med en sluttning inuti för attsand och damm ska rinna ut.Inspiration har kommit från tidigare rovrar som varit/är aktiva på månen och Mars dådet är beprövade koncept som visat sig vara stabila och pålitliga. Tidigareexamensarbeten har kommit fram till att det chassi som ska användas är snarlikt detsom använts på Mars Science Laboratory Curiosity och Mars Exploration Rover’sSpirit och Opportunity.Projektet började på Högskolan i Halmstad 2013 och tidigare projekt har tittat påbland annat chassit, energisystem och utplaceringsenheten. Årets projekt har tagithänsyn till resultat från tidigare år, för att ett koncept på en hel rover slutligen skakunna visas upp för NASA Jet Propulsion Laboratory.Examensarbetet är genomfört i samarbete med NASA:s Jet Propulsion Laboratory iKalifornien, USA, vilka är USA:s center för robotisk utforskning av solsystemet.
45
Mier, Hicks Fernando. "Characterization on a magnetically levitated testbed for electrospray propulsion systems." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/90781.
Full textAbstract:
Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 81-82).
Small satellites are changing the space scene dramatically. By drastically reducing costs while still having impressive technological capabilities, their popularity among the space community is increasing at a very fast rate. Propulsion systems for these class of spacecraft are very limited. One promising technology is the ion Electrospray Propulsion System (iEPS) developed at the Space Propulsion Laboratory at MIT. Electrosprays accelerate ions present in the interface between an ionic liquid and vacuum using strong electric fields. Current thrust estimates for the iEPS modules land in the vicinity of tens of [mu]Newtons. Measuring the small thrust produced by the devices is challenging to say the least. This thesis presents the design and development of a Magnetically Levitated Thrust Balance (MLTB) for thrust estimation of the iEPS devices. The MLTB levitates an engineering model of a small satellite using magnetic fields inside a vacuum chamber. The zero friction environment is exploited to measure the minute thrust levels produced by the electrospray thrusters. Additional sensors and actuators that provide added functionality to the instrument are also explained. A fully stand-alone Power Processing Unit (PPU) capable of generating and delivering the high voltage signals needed to drive the thrusters is explained in detail. Test results of charging behavior and lifetime characterization of the emitted current are presented as a preliminary exploration of these processes.
by Fernando Mier Hicks.
S.M.
46
Ciaramella, Konrad Mark. "The potential for matrix conversion in marine electric propulsion systems." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1444578/.
Full textAbstract:
The growing interest in marine electric propulsion is driven by the need to improve ship performance. This thesis presents a review of existing marine electric propulsion technology and potential future variable speed drives. The matrix converter was found to be a promising alternative to existing technology and this thesis describes an investigation into its potential for marine electric propulsion. The matrix converter performs direct AC-AC conversion using a high switching frequency to produce high- quality converter waveforms. The investigations were carried out using a 10kVA laboratory matrix converter and a series of computer models. The laboratory matrix converter employed IGBT bi-directional switches operated by a custom-built stand-alone control system employing various Venturini algorithms. The completed system was then used to investigate the performance of the matrix converter, examine the operational effect of different switch sequences on loss and converter input and output waveform harmonics. Computer models of the various control algorithms were developed and verified against results produced by the laboratory matrix converter and further developed for more detailed investigation. An examination of switch commutation and the effect on loss is reported and this led to the development of a novel commutation strategy named 'Opti-Soft'. This strategy maximises 'natural' current commutation in the matrix converter and balances switching loss across devices without increasing total loss above existing switching strategies. The results from the computer models show the 'Opti-Soft' strategy to possess a similar harmonic characteristic to the conventional strategy allowing the use of existing filter designs. The design of a conceptual marine matrix converter drive and ancillary equipment is also considered and its performance investigated. The problems of reduced supply utilisation, topology selection, cooling and protection are examined. A novel mode of operation that takes advantage of the matrix converter's unrestricted output frequency is proposed. The conclusions discuss the findings of the study and relate the practical issues that will need to be overcome before the matrix converter can be considered for marine use.
47
Hartwig, Jason W. "Liquid Acquisition Devices for Advanced In-Space Cryogenic Propulsion Systems." Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1396562473.
Full text
48
Bosi, Franco Javier. "Development of global models of plasma systems for space propulsion." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3427114.
Full textAbstract:
The focus of this research work is to develop plasma global models, to support the investigations on argon and carbon dioxide helicon plasma thruster, carried out at CISAS research center.
These models have been applied in three different and consecutive research programs, the EU FP7 HpH.com program, the AO7048 ESA program, and the SAPERE-STRONG MIUR program.
The models have been developed for the most general case of an electronegative magnetized discharge, therefore encompass all types of cold non magnetized or electropositive discharges.
Furthermore, the models employs results from particle in cell simulations of the plasma exhaust plume, in order to account properly for the plasma detachment and acceleration provided by the so called magnetic nozzle effect.
The simulations are in agreement with performed experiments on the laboratory set up, and allow prediction of the thruster propulsive performances.
The viability of plasma assisted combustion for monopropellant propulsion applications, is also investigated. An experimental proof of concept is provided with a nitrous oxide gliding arc experiment, carried out at Drexel Plasma Institute. The experiment shows that the plasma is effective in promoting catalytic decomposition and combustion of the gas.
A global model is developed to investigate the mechanism of nitrous oxide plasma assisted dissociation; the model implements non-equilibrium neutral gas phase reaction rates and a vibrational energy equation for the estimation of the vibrational temperature.
The model is able to reveal the mechanism of plasma catalysis, and predicts good performances for an hypothetical nitrous oxide microwave discharge thruster.Obiettivo di questo lavoro è lo sviluppo di modelli globali di plasma atti a supportare lo studio della propulsione al plasma di tipo helicon, con propellente ad argon e anidride carbonica, portato avanti al centro di ricerca ed attività spaziali CISAS. I modelli sono stati applicati in tre progetti di ricerca consecutivi: il progetto HpH.com, finanziato nel contesto del programma europeo FP7, il progetto AO7048 finanziato da ESA ed il progetto STRONG-SAPERE finanziato dal MIUR. I modelli sono sviluppati in via generale per plasmi di gas elettronegativo e magnetizzato, perciò sono applicabili alle sottocategorie di plasmi freddi, non magnetizzati o elettropositivi. I modelli inoltre, incorporano risultati da simulazioni di tipo paticle in cell, della zona del plume del propulsore; in questo modo è possibile tener conto degli effetti di distacco e accelerazione del plasma, provocati dalla divergenza delle linee del campo magnetico; il cosiddetto effetto di ugello magnetico. E' inoltre studiata la fattibilità della combustione assistita da plasma, per applicazioni relative a propulsione monopropellente. Una verifica sperimentale di fattibilità è effettuata attraverso un esperimento di scarica di tipo gliding arc, di protossido d'azoto; l'esperimento è stato effettuato presso il Drexel Plasma Institute a Philadelphia. Un modello globale di plasma è stato sviluppato per studiare i meccanismi della dissociazione assistita da plasma; il modello implementa reazioni di fase neutra di non equilibrio, e una equazione per l'evoluzione dell'energia vibrazionale delle molecole, che permette di tracciare l'andamento temporale della temperatura vibrazionale. Il modello è in grado di evidenziare i meccanismi di catalisi da plasma; inoltre, predice buone prestazioni per un eventuale propulsore di tipo plasma a microonde con protossido d'azoto.
49
Vásquez, Cristian Andrés Morales. "A methodology to select the electric propulsion system for Platform Supply Vessels (PSV)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-26122014-164655/.
Full textAbstract:
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.
50
Belapurkar, Rohit K. "Stability and Performance of Propulsion Control Systems with Distributed Control Architectures and Failures." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1357309068.
Full text