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  • 1. Agarwal, Anurag
    et al.
    Dowling, Ann P.
    Shin, Ho-Chul
    Graham, Will
    Sefi, Sandy
    KTH, School of Computer Science and Communication (CSC), Numerical Analysis and Computer Science, NADA.
    Ray-tracing approach to calculate acoustic shielding by a flying wing airframe2007In: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 45, no 5, p. 1080-1090Article in journal (Refereed)
    Abstract [en]

    The "silent aircraft" is in the form of a flying wing with a large wing planform and a propulsion system that is embedded in the rear of the airframe with intakes on the upper surface of the wing. Thus a large part of the forward-propagating noise from the intake ducts is expected to be shielded from observers on the ground by the wing. Acoustic shielding effects can be calculated by solving an external acoustic scattering problem for a moving aircraft. In this paper, acoustic shielding effects of the silent aircraft airframe are quantified by a ray-tracing method. The dominant frequencies from the noise spectrum of the engines are sufficiently high for ray theory to yield accurate results. It is shown that, for low-Mach number homentropic flows, a condition satisfied approximately during takeoff and approach, the acoustic rays propagate in straight lines. Thus, from Fermat's principle it is clear that classical geometrical optics and geometrical theory of diffraction solutions are applicable to this moving-body problem as well. The total amount of acoustic shielding at an observer located in the shadow region is calculated by adding the contributions from all the diffracted rays (edge-diffracted and creeping rays) and then subtrading the result from the incident field without the airframe. The three-dimensional ray-tracing solver is validated by comparing the numerical solutions with analytical high-frequency asymptotic solutions for canonical shapes. Experiments on a model-scale geometry have been conducted in an anechoic chamber to test the applicability of the ray-tracing technique. The results confirm the accuracy of the approach, which is then applied to a CAD representation of a prototype silent aircraft design. As expected, the flying wing configuration provides very significant ground shielding (in excess of 10 dB at all locations) of a source above the airframe.

  • 2.
    Aghaali, Habib
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Ångström, Hans-Erik
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Turbocharged SI-Engine Simulation with Cold and Hot-Measured Turbocharger Performance Maps2012In: Proceedings of ASME Turbo Expo 2012, Vol 5, ASME Press, 2012, p. 671-679Conference paper (Refereed)
    Abstract [en]

    Heat transfer within the turbocharger is an issue in engine simulation based on zero and one-dimensional gas dynamics. Turbocharged engine simulation is often done without taking into account the heat transfer in the turbocharger. In the simulation, using multipliers is the common way of adjusting turbocharger speed and parameters downstream of the compressor and upstream of the turbine. However, they do not represent the physical reality. The multipliers change the maps and need often to be different for different load points. The aim of this paper is to simulate a turbocharged engine and also consider heat transfer in the turbocharger. To be able to consider heat transfer in the turbine and compressor, heat is transferred from the turbine volute and into the compressor scroll. Additionally, the engine simulation was done by using two different turbocharger performance maps of a turbocharger measured under cold and hot conditions. The turbine inlet temperatures were 100 and 600°C, respectively. The turbocharged engine experiment was performed on a water-oil-cooled turbocharger (closed waste-gate), which was installed on a 2-liter gasoline direct-injected engine with variable valve timing, for different load points of the engine. In the work described in this paper, the difference between cold and hot-measured turbocharger performance maps is discussed and the quantified heat transfers from the turbine and to/from the compressor are interpreted and related to the maps.

  • 3. Ahlgren, Niklas
    et al.
    Karlsson, Thomas
    Larsson, Robin
    Spacecraft Department, OHB Sweden, Sweden.
    Noteborn, Ron
    PRISMA Mission Extension: Adapting Mission Operations to New and Changing Mission Objectives2012In: SpaceOps 2012 Conference, American Institute of Aeronautics and Astronautics, 2012Conference paper (Refereed)
    Abstract [en]

    The PRISMA in-orbit test-bed was launched in June 2010 to demonstrate strategies and technologies for formation flying and rendezvous. OHB Sweden is the prime contractor for the project which is funded by the Swedish National Space Board (SNSB) with support from DLR, CNES, and DTU. In early September of 2011, 15 months after launch, all primary mission objectives of the PRISMA formation flying satellites had been achieved and mission success was declared. Since a significant amount of delta-V capability still remained an open call for new experiments was issued, inviting both old and new experimenters to use the capabilities of the formation. Several interested parties took the opportunity to perform their own experiments with an existing platform, each coming with new mission objectives not previously planned to be flown on the PRISMA satellites. Some of these experiments were close to what had already been achieved within the nominal mission, but some included new ways of using the formation not envisioned by the spacecraft designers. The new experiments span from data collection in specific relative orbits, with a separation from a few meters to several kilometers, to entirely new modules within the on-board software. Changing from a pre-planned technology demonstration mission to operating a commercial resource required adaptation of the original operational concept, taking into account the different levels of experience of the customers and managing the satellites between experiments. This paper describes how these new mission objectives were integrated in operations and how a sometimes very short turn-around between initial concept and experiment execution was implemented with the aid of well established validation processes, high degrees of on-board autonomy and a flexible operations team.

  • 4.
    Alaniz, Monica
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Belyayev, Serhiy
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Bergman, David
    Casselbrant, Gustav
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Honeth, Mark
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Huang, Jiangwei
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Laukkanen, Mikko
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Michelsen, Jacob
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Pronenko, Vira
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Paulson, Malin
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Schlick, Georg
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Valle, Mario
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    The SQUID sounding rocket experiment2011In: Proceedings of the 20th ESA Symposium on European Rocket and Balloon Programmes and Related Research, European Space Agency, 2011, p. 159-166Conference paper (Refereed)
    Abstract [en]

    The objective of the SQUID project is to develop and in flight verify a miniature version of a wire boom deployment mechanism to be used for electric field measurements in the ionosphere. In February 2011 a small ejectable payload, built by a team of students from The Royal Institute of Technology (KTH), was launched from Esrange on-board the REXUS-10 sounding rocket. The payload separated from the rocket, deployed and retracted the wire booms, landed with a parachute and was subsequently recovered. Here the design of the experiment and post fight analysis are presented.

  • 5.
    Allam, Sabry
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Åbom, Mats
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Marcus Wallenberg Laboratory MWL.
    Advanced experimental procedure for in-duct aero-acoustics2006In: 13th International Congress on Sound and Vibration 2006, ICSV 2006, 2006, p. 1185-1192Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to present a method for characterization of in-duct aero-acoustic sources that can be described as active acoustic two-ports. The method is applied to investigate the sound produced from an orifice plate. The motivation is to obtain better data for the development of improved prediction methods for noise from flow singularities, e.g., in HVAC systems on aircrafts. Most of the earlier works fall into two categories; papers modeling the scattering of acoustic waves and papers modeling the sound generation. Concerning the scattering it is possible to obtain estimates of the low frequency behavior from linear perturbations of the steady state equations for the flow. Concerning the sound generation most of the presented work is experimental and follows a paper by Nelson&Morfey, which present a scaling law procedure for the in-duct sound power based on a dipole model of the source. One limitation with the earlier works is that the sound power only was measured on the downstream side. Also data was only obtained in 1/3-octave bands, by measuring the sound radiated from an open duct termination. Assuming plane waves and linear acoustics the flow duct singularity can be completely modeled as an active 2-port. The experimental determination of its properties is done in a two steps procedure. In the first step the passive data, i.e., the scattering matrix S, is determined using external (independent) sources. In the second step the S matrix is used and the source vector is determined by testing the system with known acoustic terminations.

  • 6.
    Ambre, Rombaut
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Landing the Propellant Stage of a launcher2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To reduce the cost of launch, several aerospace companies are exploring the possibility of partly reusable launchers. In order to be reusable with minimum refurbishment cost the reusable part of the launcher has to suffer little damage and land in optimal conditions. In this paper, a guidance algorithm to achieve the return of the reusable vehicle on ground through a vertical landing is described. Different mission scenarios are taken into account and the performance of the guidance algorithm is assessed using a 6 Degrees Of Freedom simulator.

  • 7. Amoignon, Olivier
    et al.
    Pralits, Jan O.
    Hanifi, Ardeshir
    Swedish Defence Research Agency.
    Berggren, M.
    Henningson, Dan S.
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Shape optimization for delay of laminar-turbulent transition2006In: AIAA Journal, ISSN 0001-1452, E-ISSN 1533-385X, Vol. 44, no 5, p. 1009-1024Article in journal (Refereed)
    Abstract [en]

    A method using gradient-based optimization is introduced for the design of wing profiles with the aim of natural laminar How, as well as minimum wave drag. The Euler equations of gasdynamics, the laminar boundary-layer equations for compressible flows on infinite swept wings, and the linear parabolized stability equations (PSE) are solved to analyze the evolution of convectively unstable disturbances. Laminar-turbulent transition is assumed to be delayed by minimizing a measure of the disturbance kinetic energy of a chosen disturbance, which is computed using the PSE. The shape gradients of the disturbance kinetic energy are computed based on the solutions of the adjoints of the state equations just named. Numerical tests are carried out to optimize the RAE 2822 airfoil with the aim to delay simultaneously the transition, reduce the pressure drag coefficient, and maintain the coefficients of lift and pitch moments. Constraints are also applied on the geometry. Results show a reduction of the total amplification of a large number of disturbances, which is assumed to represent a delay of the transition in the boundary layer. Because delay of the transition implies reduction of the viscous drag, the present method enables shape optimization to perform viscous drag reduction.

  • 8. Anton, N.
    et al.
    Genrup, M.
    Fredriksson, C.
    Larsson, P. -I
    Christiansen Erlandsson, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    Axial turbine design for a twin-turbine heavy-duty turbocharger concept2018In: Proceedings of the ASME Turbo Expo, ASME Press, 2018Conference paper (Refereed)
    Abstract [en]

    In the process of evaluating a parallel twin-turbine pulseturbocharged concept, the results considering the turbine operation clearly pointed towards an axial type of turbine. The radial turbine design first analyzed was seen to suffer from suboptimum values of flow coefficient, stage loading and blade-speed-ratio. Modifying the radial turbine by both assessing the influence of "trim" and inlet tip diameter all concluded that this type of turbine is limited for the concept. Mainly, the turbine stage was experiencing high values of flow coefficient, requiring a more high flowing type of turbine. Therefore, an axial turbine stage could be feasible as this type of turbine can handle significantly higher flow rates very efficiently. Also, the design spectrum is broader as the shape of the turbine blades is not restricted by a radially fibred geometry as in the radial turbine case. In this paper, a single stage axial turbine design is presented. As most turbocharger concepts for automotive and heavy-duty applications are dominated by radial turbines, the axial turbine is an interesting option to be evaluated for pulsecharged concepts. Values of crank-angle-resolved turbine and flow parameters from engine simulations are used as input to the design and subsequent analysis. The data provides a valuable insight into the fluctuating turbine operating conditions and is a necessity for matching a pulse-turbocharged system. Starting on a 1D-basis, the design process is followed through, resulting in a fully defined 3D-geometry. The 3Ddesign is evaluated both with respect to FEA and CFD as to confirm high performance and durability. Turbine maps were used as input to the engine simulation in order to assess this design with respect to "on-engine" conditions and to engine performance. The axial design shows clear advantages with regards to turbine parameters, efficiency and tip speed levels compared to a reference radial design. Improvement in turbine efficiency enhanced the engine performance significantly. The study concludes that the proposed single stage axial turbine stage design is viable for a pulse-turbocharged sixcylinder heavy-duty engine. Taking into account both turbine performance and durability aspects, validation in engine simulations, a highly efficient engine with a practical and realizable turbocharger concept resulted.

  • 9. Anton, N.
    et al.
    Genrup, M.
    Fredriksson, C.
    Larsson, P. -I
    Christiansen Erlandsson, Anders
    KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.), Internal Combustion Engines.
    On the choice of turbine type for a twin-turbine heavy-duty turbocharger concept2018In: Proceedings of the ASME Turbo Expo, ASME Press, 2018Conference paper (Refereed)
    Abstract [en]

    In this study, a fundamental approach to the choice of turbocharger turbine for a pulse-charged heavy-duty diesel engine is presented. A standard six-cylinder engine build with a production exhaust manifold and a Twin-scroll turbocharger is used as a baseline case. The engine exhaust configuration is redesigned and evaluated in engine simulations for a pulse-charged concept consisting of a parallel twin-turbine layout. This concept will allow for pulse separation with minimized exhaust pulse interference and low exhaust manifold volume. This turbocharger concept is uncommon, as most previous studies have considered two stage systems, various multiple entry turbine stages etc. Even more rare is the fundamental aspect regarding the choice of turbine type as most manufacturers tend to focus on radial turbines, which by far dominate the turbochargers of automotive and heavy-duty applications. By characterizing the turbine operation with regards to turbine parameters for optimum performance found in literature a better understanding of the limitations of turbine types can be achieved. A compact and low volume exhaust manifold design is constructed for the turbocharger concept and the reference radial turbine map is scaled in engine simulations to a pre-set AFRtarget at a low engine RPM. By obtaining crank-angle-resolved data from engine simulations, key turbine parameters are studied with regard to the engine exhaust pulse-train. At the energetic exhaust pressure pulse peak, the reference radial turbine is seen to operate with suboptimum values of Blade-Speed-Ratio, Stage Loading and Flow Coefficient. The study concludes that in order to achieve high turbine efficiency for this pulse-charged turbocharger concept, a turbine with efficiency optimum towards low Blade-Speed Ratios, high Stage Loading and high Flow Coefficient is required. An axial turbine of low degree of reaction-design could be viable in this respect.

  • 10.
    Aoudia, Thomas
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Aircraft Performance Monitoring on Contaminated Runways2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Operations on contaminated runways are a permanent challenge for the aviation community. Among the stakeholders, Airbus has decided to improve its knowledge by developing a fast post-processing software aiming at quickly identifying the runway state on operational recordings. First and foremost, the context of operations on contaminated runways is presented, with a particular emphasis on runway condition assessment methods. In a second part, the models embedded in this function are validated against simulation and more elaborated flight test analysis software. Then, the identification algorithm is validated by comparing its outputs to actual operational conditions. Finally, the robustness of the identification is assessed.

  • 11.
    Arnal, Daniel
    et al.
    ONERA.
    Tran, Dac
    Dassault Aviation.
    Hein, Stefan
    DLR.
    Hanifi, Ardeshir
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. KTH, School of Engineering Sciences (SCI), Centres, Linné Flow Center, FLOW.
    Engelbrecht, T.
    SUPERsonic TRAnsition Control Contract N° AST4-CT-2005-516100: Final Technical Report2008Report (Other academic)
  • 12. Austrin, L.
    et al.
    Torabzadeh Tari, Mohsen
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Larsson, A.
    Analysis of a feasible pulsed-power supply system for an Unmanned Aerial Vehicle2006In: ICAS-Secretariat, 2006, p. 3605-3612Conference paper (Refereed)
    Abstract [en]

    More Electric Aircraft technology enables the power supply of electric energy weapons such as high-power microwave and laser weapons. Aspects of electric power generation, energy storage, distribution and pulse-conditioning systems for the power supply of directed energy weapons in Unmanned Aerial Vehicle are addressed in this paper. A trend in aircraft design is to electrify more parts of the aircraft via the concept of More Electric Aircraft (MEA) and its technology which allows for increased electric power consumption. Thus, MEA technology enables the power supply of weapons and protection systems that are using electric energy. Among these devices directed energy weapons such as high-power microwave (HPM) and laser weapons are feasible. Such systems require high power pulsed electric energy with, thus imposing new requirements of on-board power supplies. In the demonstrated concept it is important to analyze power losses and efficiency as well as weight and volume in order to evaluate the possibility to adapt the system in an UAV.

  • 13.
    Ballard, Claire
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Conceptual lay-out of small launcher2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
  • 14.
    Ballard, Claire
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Conceptual lay-out of small launcher2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The objective of this diploma thesis is to perform a conceptual lay-out of a small launcher. Re- quirements have been defined in order to realize this first preliminary study and design of a small launcher. In that frame, a MATLAB code has been written in order to simulate the rocket tra- jectories. An optimization program on launcher staging has been written as well. To validate this code, the VEGA and Ariane 5 launchers have been used. Then from studies on existing launchers, simulations have been performed in order to find an optimum small launcher and later on to design more precisely the small launcher. As a requirement an upper stage has been newly designed for the purpose of the study. At the end, two small launchers have been considered: a three-stage launcher using the Zefiro 23 as a first stage, the Zefiro 9 as a second stage, and an upper stage using a 3kN thrust engine; a two-stage launcher using the Zenit booster engine in the first stage, and an upper stage using a 22kN thrust engine.

  • 15. Balmer, G.
    et al.
    Berquand, A.
    Company-Vallet, E.
    Granberg, V.
    Grigore, V.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Kevorkov, R.
    Lundkvist, E.
    Olentsenko, Georgi
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Pacheco-Labrador, J.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Yuan, Yunxia
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    ISAAC: A REXUS STUDENT EXPERIMENT TO DEMONSTRATE AN EJECTION SYSTEM WITH PREDEFINED DIRECTION2015In: EUROPEAN ROCKET AND BALLOON: PROGRAMMES AND RELATED RESEARCH, 2015, p. 235-242Conference paper (Refereed)
    Abstract [en]

    ISAAC - Infrared Spectroscopy to Analyse the middle Atmosphere Composition was a student experiment launched from SSC's Esrange Space Centre, Sweden, on 29th May 2014, on board the sounding rocket REXUS 15 in the frame of the REXUS/BEXUS programme. The main focus of the experiment was to implement an ejection system for two large Free Falling Units (FFUs) (240 mm x 80 mm) to be ejected from a spinning rocket into a predefined direction. The system design relied on a spring-based ejection system. Sun and angular rate sensors were used to control and time the ejection. The flight data includes telemetry from the Rocket Mounted Unit (RMU), received and saved during flight, as well as video footage from the GoPro camera mounted inside the RMU and recovered after the flight. The FFUs' direction, speed and spin frequency as well as the rocket spin frequency were determined by analyzing the video footage. The FFU-Rocket-Sun angles were 64.3 degrees and 104.3 degrees, within the required margins of 90 degrees +/- 45 degrees. The FFU speeds were 3.98 m/s and 3.74 m/s, lower than the expected 5 +/- 1 m/s. The FFUs' spin frequencies were 1.38 Hz and 1.60 Hz, approximately half the rocket's spin frequency. The rocket spin rate slightly changed from 3.163 Hz before the ejection to 3.117 Hz after the ejection of the two FFUs. The angular rate, sun sensor data and temperature on the inside of the rocket module skin were also recorded. The experiment design and results of the data analysis are presented in this paper.

  • 16.
    BENETHUILLERE, Quentin
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

     

  • 17.
    BENETHUILLERE, Quentin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Independent thesis Advanced level (degree of Master (Two Years)), 20 HE creditsStudent thesis
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

  • 18.
    BENETHUILLERE, Quentin
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Revision Of The Aircraft Engines Preliminary Design Platform Of First Level2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the highly competitive aerospace industry, engine manufacturers must react very quickly and precisely to any demand emerging from aircraft manufacturers if they want to be positioned on the offer. This is especially true when answering to Requests For Information (RFI) based on preliminary design investigations of first level. In order to reduce the time needed to perform these costly operations while improving the performances achieved, Snecma wishes to develop tools for dimensioning the engine and also for assessing key parameters such as mass, emissions, fuel burn, costs, etc. Unfortunately, the set of tools and the process used at the present time for preliminary design investigations of first level are not sufficient to meet the high standards sought-after by the company in terms of time and performances. As a consequence, efforts must be spent on redefining the whole process and the tools it is based on; here is the mission that has been conferred upon me.

     

    Multiple exchanges with performances engineers and specialists allowed to draw the current process for preliminary design investigations of first level and raise all the associated concerns. At the same time, a status of the existing tools (called modules in this report), mainly developed under Excel, has been realised in order to identify the range of action for today's investigations. A prototype has been developed under SDK Python with the aim of proving the feasibility of a solution to a difficulty that shows up in the process for each new investigation: the one of generating the workflow on the optimisation software Optimus. A target process has finally been discussed considering all the information collected, and would allow dividing by five the time needed to perform investigations compare to now. The prototype developed lead to interesting results and this solution could thus probably be integrated in the target process as it would allow saving one day of work for an engineer for each study to be carried out.

     

    Solutions have been proposed to all the concerns identified in the process and they will have to be discussed with many actors and investigated further in the near future in order to set the target process that will allow meeting the final objective of answering all types of RFIs emitted by aircraft manufacturer in a very short time with a high level of confidence in the results.

  • 19.
    Berggren, Daniel
    KTH, Superseded Departments, Aeronautical Engineering.
    Investigation of limit cycle oscillations for a wing section with nonlinear stiffness2004In: Aerospace Science and Technology, ISSN 1270-9638, E-ISSN 1626-3219, Vol. 8, no 1, p. 27-34Article in journal (Refereed)
    Abstract [en]

    A wind tunnel experiment is designed with the objective to obtain well-behaved limit cycle oscillations for a wing section with two degrees of freedom, translation and rotation, in two-dimensional flow. This is accomplished using a setup of linear springs so that the resulting moment is a nonlinear function of the rotation angle. The experimental setup is designed so that the amplitudes of the limit cycle oscillations are sufficiently low to motivate the use of linear aerodynamics in the analysis. The experimental results are compared to analyses for two different configurations, and the agreement is fairly good.

  • 20.
    Bergman, David
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Study of the coupled interaction between the wake’s transient behavior and pressure surfaces upstream using Detached Eddy Simulation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aerodynamic sub-discipline of flow control has for many years been, and still is today, a very prominent subject of research. This field encompasses devices that produce a beneficial change in wall-bounded or free shear flows that may lead to, among many possibilities, reduced drag of ground vehicles and airplanes. The end result could have a substantial improved impact on fuel economy and also introduce new possible design options.

    Creo Dynamics AB recently started to venture into the field of active flow control with huge interest for the technology and its possible applications. One such application includes a system that reduces drag on ground vehicles via the use of active flow control. The system is composed of three components: actuators, controller and sensors. The work carried out in this thesis deals with a study into the sensory placement and control approach related to the system on a very conceptual level.

    According to Creo’s vision of the project the sensor shall record the pressure distribution and characteristics up-stream of the actuators. In turn the algorithm shall be capable of translating and correlating this data to the flow state downstream

    and in the wake. This data is then to be relayed to a control system producing the correct actuation response to achieve desired flow characteristics. For this system to work knowledge about the coupling between wake behavior and pressure distribution on surfaces upstream of the separated flow is necessary. This thesis is an initial investigation into the possible couplings that can be found. The scope also includes investigation of the coupling during cross-winds and gusts.

    Simulations of a simplified car geometry were carried out using the CFD package OpenFOAM and the DDES turbulence model. The initial investigation yielded promising results, showing that a link between the wake behavior and pressure distribution up-stream exists. But further work has to be carried out, as is discussed in the last chapter, before the algorithm according to Creo’s specifications can be constructed.

  • 21.
    Blandineau, Pauline
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Wake Vortex Encounter Detection and Severity Assessment from Flight Data2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Hazards associated to Wake Vortex Encounters (WVE) are increasing with the growing traffic and the appearance of super heavy aircrafts such as the A380. The project comes with the need from airports and airlines to clearly analyze the phenomenon by detecting WVE and quantifying their strength from Flight Data Recorder data. A tool is developed with this purpose using Roll Control Ratio as severity metric. Flight data from flight simulator are used for first analyses. The obtained results are encouraging and enable proposed improvements and consideration to further work.

  • 22.
    Blomberg, Lars
    KTH, Superseded Departments, Alfvén Laboratory.
    Micro-satellite Mission Analysis: Theory Overview and Some Examples2003Report (Other academic)
    Abstract [en]

    Rudimentary mission analysis for micro-satellites has been carried out, in particular for ionospheric/thermospheric “dipper” missions. The basic equations of orbital mechanics are summarized and commented on. General properties of near-Earth orbits are discussed and exemplified in figures and tables. In addition, a few specific mission scenarios are described and discussed.

  • 23.
    Blomberg, Lars
    et al.
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lindqvist, Per-Arne
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Bylander, Lars
    KTH, Superseded Departments, Alfvén Laboratory. KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Atrid-2: An advanced auroral microprobe1999Other (Other academic)
    Abstract [en]

    Astri-2 is an advanced auroral microprobe with dual primary mission objectives; to do high-quality in situ measurements of the physical processes behind the aurora, and to demonstrate the usefulness of microspacecraft as advanced research tools. Mission success will open up entirely new possibilities to carry out low-budget multipoint measurements in near-Earth space. This long-desired kind of in situ measurements are the next major step forward in experimental space physics. Astrid-2 has platform dimensions of 45×45×30 cm, a total mass of just below 30 kg, and carries scientific instruments for measuring local electric and magnetic fields, plasma density and density fluctuations, ions and electrons, as well as photometers for remote imaging of auroral emissions. Attitude determination is provided by a high-precision star imager. Some 250 Mbytes' worth of scientific data will be received each day at the two ground stations. Astrid-2 will be launched as a piggy-back on a Russian Kosmos-3M launcher into an 83 deg inclination circular orbit at 1000 km altitude. Nodal regression will give complete coverage of all local time sectors every 3.5 months. © 1999 Elsevier B.V. All rights reserved.

  • 24.
    Blomberg, Lars
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Marklund, Göran
    KTH, Superseded Departments, Alfvén Laboratory.
    Lindqvist, Per-Arne
    KTH, Superseded Departments, Alfvén Laboratory.
    Primdahl, F.
    Brauer, P.
    Bylander, Lars
    KTH, Superseded Departments, Alfvén Laboratory.
    Cumnock, Judy
    KTH, Superseded Departments, Alfvén Laboratory.
    Eriksson, S.
    Ivchenko, Nickolay
    KTH, Superseded Departments, Alfvén Laboratory.
    Karlsson, Tomas
    KTH, Superseded Departments, Alfvén Laboratory.
    Kullen, Anita
    KTH, Superseded Departments, Alfvén Laboratory.
    Merayo, J. M. G.
    Pedersen, E. B.
    Petersen, J. R.
    The EMMA Instrument on the Astrid-2 Micro-Satellite2003Report (Other academic)
  • 25. Bodin, Per
    et al.
    Chasset, Camille
    Larsson, Robin
    Swedish Space Corporation, Stockholm, Sweden .
    Nilsson, Fredrik
    Noteborn, Ron
    Nylund, Matti
    Vretblad, Örjan
    Veldman, Sytze
    Persson, Staffan
    Guidance, navigation, and control experiments on the PRISMA in-orbit test bed2007In: 58th International Astronautical Congress, IAC-07-C1, 2007, Vol. 7, p. 4461-4470Conference paper (Refereed)
    Abstract [en]

    PRISMA will demonstrate Guidance, Navigation and Control strategies for advanced autonomous formation flying and rendezvous. The Swedish Space Corporation (SSC) is the prime contractor for the project which is funded by the Swedish National Space Board (SNSB). The project is further supported by the German Aerospace Center (DLR), the Technical University of Denmark (DTU), and the French Space Agency (CNES). PRISMA consists of two spacecraft: MAIN and TARGET. The MAIN satellite is 3-axis stabilized and has full 3D delta-V maneuverability that is independent of the spacecraft's attitude. The TARGET satellite has a simplified, yet 3-axis stabilizing, magnetic attitude control system and no orbit maneuver capability. This paper presents the PRISMA Guidance, Navigation, and Control (GNC) subsystem. The paper gives a mission summary and an overview of the GNC subsystem with its hardware and software configuration. It also explains how the orbit control functions contain advanced fuel optimal Model Predictive Control (MPC). It is shown how the GNC software is developed using model based automatic coding technology implemented with Matlab/Simulink. The paper then summarizes the different GNC experiments to be performed by SSC. Finally, an overview of the test approach for the subsystem is given.

  • 26. Bodin, Per
    et al.
    Larsson, Robin
    Swedish Space Corporation, Sweden.
    Nilsson, Fredrik
    Chasset, Camille
    Noteborn, Ron
    Nylund, Matti
    PRISMA: an in-orbit test bed for guidance, navigation, and control experiments2009In: Journal of Spacecraft and Rockets, ISSN 0022-4650, E-ISSN 1533-6794, Vol. 46, no 3, p. 615-623Article in journal (Refereed)
    Abstract [en]

    This paper presents system-level hardware-in-the-loop real-time simulation results for three different guidance, navigation, and control experiments designed for in-flight demonstration on the PRISMA formation-flying satellite mission. The mission consists of two spacecraft: Main and Target The Main satellite has full orbit control capability, whereas Target is attitude-controlled only. Launch is planned for November 2009. The simulation results presented demonstrate the feasibility and readiness for flight as well as the expected in-flight performance. The three experiments include Global Positioning System and vision-based formation flying for two spacecraft in both passive and forced motion. In addition to these simulation results, the paper gives an overview of the PRISMA mission in general and the guidance, navigation, and control experiments in particular. The hardware-in-the-loop real-time test environment is also presented.

  • 27. Bodin, Per
    et al.
    Noteborn, Ron
    Larsson, Robin
    Swedish Space Corporation, Sweden.
    Chasset, Camille
    System test results from the GNC experiments on the PRISMA in-orbit test bed2011In: Acta Astronautica, ISSN 0094-5765, E-ISSN 1879-2030, Vol. 68, no 7, p. 862-872Article in journal (Refereed)
    Abstract [en]

    The PRISMA in-orbit test bed will demonstrate guidance, navigation, and control strategies for spacecraft formation flying and rendezvous. The project is funded by the Swedish National Space Board and the prime contractor is the Swedish Space Corporation. The project is further supported by the German Aerospace Center, the Technical University of Denmark, and the French Space Agency. PRISMA was launched on June 15, 2010 and after three weeks of operations, all on-board systems and units have passed an initial commissioning phase. Separation of the two PRISMA satellites from each other is expected by mid-August 2010. PRISMA consists of two spacecraft: MAIN and TARGET. The MAIN spacecraft has full orbit control capability while TARGET is attitude controlled only. The Swedish Space Corporation is responsible for three groups of guidance, navigation, and control experiments. These experiments include GPS- and vision-based formation flying during which the spacecraft will fly in passive as well as forced motion. The three experiments are: autonomous formation flying, proximity operations with final approach/recede maneuvers, and autonomous rendezvous. This paper presents system test results from two of these experiments as obtained with the flight-ready system. The system tests consist of a series of simulations performed on the flight model spacecraft with a large amount of hardware in the loop.

  • 28. Bodin, Per
    et al.
    Noteborn, Ron
    Larsson, Robin
    OHB Sweden AB, AOCS & SW Dept, Sweden..
    Karlsson, Thomas
    D’Amico, Simone
    Ardaens, Jean Sebastien
    Delpech, Michel
    Berges, Jean-Claude
    The Prisma Formation Flying Demonstrator: Overview and Conclusions from the Nominal Mission2012In: Advances in the Astronautical Sciences, ISSN 0065-3438, Vol. 144, p. 441-460Article in journal (Refereed)
    Abstract [en]

    The PRISMA in-orbit testbed was launched on June 15, 2010 to demonstrate strategies and technologies for formation flying and rendezvous. OHB Sweden (OHB-SE) is the prime contractor for the project which is funded by the Swedish National Space Board with additional support from the German Aerospace Center (DLR), the French National Space Center (CNES), and the Technical University of Denmark (DTU). In August 2011, PRISMA completed its nominal mission and during the fall of 2011, several additional activities have been performed under a mission extension program. The mission qualifies a series of sensor and actuator systems including navigation using GPS, Vision Based and RF technology as well as a propulsion system based on environmentally friendly propellant technology. The mission also includes a series of GNC experiments using this equipment in closed loop. Separate experiments are implemented by OHB-SE, DLR, and CNES and the paper provides an overview and conclusions from the nominal mission flight results from these experiments.

  • 29.
    Bordogna, Marco Tito
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Fidjeland, Leo
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Fjällid, Markus
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Galrinho, Miguel
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Haponen, Anders
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Hou, Anton
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Ivchenko, Nickolay
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Kristmundsson, Darri
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    Lárusdóttir, Ólafía
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lejon, Marcus
    KTH, School of Engineering Sciences (SCI), Mechanics.
    Lindh, Marcus
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Lozano, Emilio
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Magnusson, Patrick
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Myleus, Andreas
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Oakes, Ben D.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tibert, Gunnar
    KTH, School of Engineering Sciences (SCI), Mechanics, Structural Mechanics.
    MUSCAT experiment: active free falling units for in situ measurements of temperature and density in the middle atmosphere2013In: European Space Agency: (Special Publication) ESA SP / [ed] L. Ouwehand, ESTEC, Noordwijk, The Netherlands: ESA Communications , 2013, p. 575-582Conference paper (Other academic)
    Abstract [en]

    The main scientific objective of the MUSCAT Experimentis to develop a technique to reconstruct temperatures and density profiles in the middle atmosphere using active spherical probes. The MUSCAT experiment was launched on May 9, 2013 on the REXUS-13 sounding rocket from Esrange, in northern Sweden. The experiment ejected four probes that collected raw GPS signal. The experiment design and preliminary results are presented here.

  • 30.
    Borg, Adrian
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Space Technology.
    Development of ADCS Software Models for Use with *craft2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report details the development of a software model of an ADCS to form part of the *craft mission design tool, a software design tool used in conjunction with the hardware-in-the-loop testbed, NANOBED. Models for the ADCS have been developed, using Clyde Space Ltd systems as benchmarks, and include sub-models for actuators. The objective for these models is to provide data on power consumption and torques produced by the ADCS throughout an operational simulation, which along with models of other systems gives an indication of the feasibility of a satellite’s mission configuration. The control algorithms which define the logic behind the ADCSs have been discussed and implemented, taking into account effort limitations and distribution to the configuration of actuators. Simulations for several ADCS operational modes were performed and the results were as expected, with the ADCS following the requirements for each mode.

  • 31.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Robust Aeroelastic Analysis in the Laplace Domain: The μ-p Method2007In: IFASD 2007: International Forum on Aeroelasticity and Structural Dynamics, 2007Conference paper (Other academic)
    Abstract [en]

    In this work the so-called μ-k method for robust flutter analysis is generalized to theLaplace domain. Although the generalization as such is a straightforward matter, the resultingμ-p method is far more versatile than the previous formulation. With the new method, a singlestructured singular value (or μ) evaluation can be used to determine if a certain eigenvalue p is asolution to the uncertain flutter equation or not. This result makes it possible to compute regionsof feasible eigenvalues in the complex plane, as well as extreme eigenvalues that can be used topredict damping bounds and perform robust flutter analysis. The capability to predict dampingbounds at any flight condition is a very attractive feature of the μ-p method, as flight testing israrely taken to the flutter point. This feature also makes it possible to estimate the magnitude ofthe uncertainty based on the measured frequency and/or damping of a particular mode, whichcan reduce the potential conservativeness of the robust analysis. Finally, the capabilities of thenew method is demonstrated by applying it to a low-speed wind tunnel model.

  • 32.
    Borglund, Dan
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Upper-bound flutter speed estimation using the mu-k method2005In: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 42, no 2, p. 555-557Article in journal (Refereed)
    Abstract [en]

    The use of upper-bound μ-k estimation method in the development of robust flutter analysis and flutter testing, was described. Since only the frequency-domain aerodynamic forces are required to compute μ(k), established aerodynamic methods can be used for the robust flutter analysis. A robust flutter analysis considering wing-tip aerodynamic uncertainty was developed in MATLAB® for a wind-tunnel model in low-speed airflow. The results show that the extended procedure for robust flutter analysis was successfully applied to a wind-tunnel model in low-speed airflow.

  • 33.
    Borglund, Dan
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Ringertz, Ulf
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Solution of the uncertain flutter eigenvalue problem using the μ-p method2009In: IFASD 2009: International Forum on Aeroelasticity and Structural Dynamics, 2009Conference paper (Other academic)
  • 34.
    Boschian, Julien
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Flight Dynamics.
    Flight pro le support on simulators2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper deals with the adaptation of a flight-test tool on A350 simulators in order to support a flight profile. This adaptation has been performed by doing first, an anal- ysis of the current situation of the existing tool on old programs like the A320 or the A330. Then, several modifications on the tool have been performed in order to adapt this tool on simulators. Finally, the validation of this tool has been done by performing several tests on A350 simulators. The difficulty of this adaptation was due to the appari- tion of new state-of-the-art technologies. The main improvement concerned the signals technology that appeared from the A380. Therefore, a modification on the parameters acquisition process has been done to take into account these improvements. Finally, the implementation of this mock-up on A350 simulators consists in a feasibility study that enables simulator test engineers to automate the tests performed on simulators and to do a traceability of these tests. The realisation of this mock-up is necessary because the simulator test engineers need this tool for the end of 2012 in order to develop the A350 whereas the real evolution of this tool will be done when the real aircraft A350 will be produced in 2014.

  • 35.
    Boucly, Marceau
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Enhanced risk factor analysis of the external fire following an uncontained engine rotor failure on the A350XWB2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The risk factor study of the external fire following an uncontained engine rotor

    failure on the A350 XWB has been performed in this report. As a background, the

    engine failure model is presented as well as the way the EASA certification

    requirements lead to a risk factor creation to moderate the risk. Key in-service

    events were then investigated giving information relative to the engine failure and

    the emergency evacuation following an external fire in order to set the model of

    the external fire and its hypotheses. Four main scenarios were pointed out: single

    wing shots, cross wing shots, own pylon impacted and opposite pylon impacted. In

    a second time, risk factors were developed taking into account the flight phase

    exposure, the fuel tank filling, the fuel ignition, the engine detachment direction

    and finally the emergency evacuation. The residual risk quantification process was

    then performed through the risk volume creation, the impact trajectories

    simulation, the logical combination of targets and the risk window exploitation with

    the new risk factors for all scenarios. The external fire total isolated contribution

    has been calculated equal to 8.7% of 1 in 20 probability thanks to the enhanced

    risk factor approach that refine the risk. The scenarios cross wing shots, own and

    opposite pylon have catastrophic trajectories hitting the targets but not the cabin at

    the same time unlike the single wing shots scenario that sees most of its

    catastrophic trajectories impacting also the cabin, which prevents from performing

    an easy emergency evacuation. The design precaution on the fuel tanks with the

    distinction center tank/wing tank in the fuel filling risk factor has also shown

    effective results because one-third-disc fragments never impact the wing tanks.

    This study gathers many opportunities about the external risk factors development

    but it shows also that the risk factors have a deep impact on the residual risk

    quantification in the certification process.

  • 36.
    BOUE, Yoan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Functional model development for Multi-Purpose Crew Vehicle using EcosimPro2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Multi-Purpose Crew Vehicle (MPCV) is a spacecraft designed to carry men to the Moon and beyond. Developing such a spacecraft requires accurate numerical models. This work presents the development of such a model for the propulsion system of MPCV, with the software EcosimPro. The EcosimPro model of a spacecraft that is similar to MPCV is studied. Its results are compared with available flight data and its accuracy is assessed. Modifications are performed on this model in order to create the MPCV propulsion system model. The MPCV model is then used for performing functional propulsion analysis.

  • 37.
    Brenning, Nils
    et al.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Axnäs, Ingvar
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Koepke, Mark
    KTH.
    Raadu, Michael A.
    KTH, School of Electrical Engineering (EES), Space and Plasma Physics.
    Tennfors, Einar
    KTH, School of Electrical Engineering (EES), Fusion Plasma Physics.
    Radiation from an electron beam in magnetized plasma: excitation of a whistler mode wave packet by interacting, higher-frequency, electrostatic-wave eigenmodes2017In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 12, article id 124006Article in journal (Refereed)
    Abstract [en]

    Infrequent, bursty, electromagnetic, whistler-mode wave packets, excited spontaneously in the laboratory by an electron beam from a hot cathode, appear transiently, each with a time duration tau around similar to 1 mu s. The wave packets have a center frequency f(W) that is broadly distributed in the range 7 MHz < f(W) < 40 MHz. They are excited in a region with separate electrostatic (es) plasma oscillations at values of f(hf), 200 MHz < f(hf) < 500 MHz, that are hypothesized to match eigenmode frequencies of an axially localized hf es field in a well-defined region attached to the cathode. Features of these es-eigenmodes that are studied include: the mode competition at times of transitions from one dominating es-eigenmode to another, the amplitude and spectral distribution of simultaneously occurring es-eigenmodes that do not lead to a transition, and the correlation of these features with the excitation of whistler mode waves. It is concluded that transient coupling of es-eigenmode pairs at f(hf) such that vertical bar f(1, hf) - f(2, hf)vertical bar = f(W) < f(ge) can explain both the transient lifetime and the frequency spectra of the whistler-mode wave packets (f(W)) as observed in lab. The generalization of the results to bursty whistler-mode excitation in space from electron beams, created on the high potential side of double layers, is discussed.

  • 38.
    BRUHAT, Jean-Frederic
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Aero-acoustic optimization of a swept fan2012Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study deals with the aerodynamics and acoustics of modern transonic fans. Today, three-dimensional design techniques make possible the creation of fan blades with enhanced performance. This project investigates two of these techniques, the sweep and dihedral controls, and their influence on supersonic shock structures and blade performance. Simultaneously, the parameters influencing fan shock noise in the intake are examined.

     

    The first objective is to determine the consequences of a forward sweep on the fan performance. A series of analyses is thus carried out on a typical fan blade in order to assess the effect of a high negative sweep introduced in the tip section. Two blades with the same geometry, except for the tip section which is swept forward, are analyzed at high rotation regimes using CFD methods. The results show that the forward sweep blade has a significantly improved stall margin but an overall lower performance.

     

    In parallel, a CFD analysis is carried out to study the fan’s acoustics. The shock noise, mostly created in the tip section of the blades, is responsible for a large percentage of the noise coming out of the engine during takeoff and cruise. The objective is to understand the propagation of shock noise in the intake and isolate relevant parameters involved in the phenomenon. It is found that the shock noise level emitted is not proportional to the fan speed, as expected. This observation is counterintuitive and leads to search which variables are relevant for the analysis of the phenomenon. The angle the shock makes with the meridional axis is found to be influential on the outgoing noise level as well as the position of the shock on the blade. Finally, a model using the shock angle and aerodynamic variables to predict the noise levels is presented and support the CFD results.

  • 39.
    Brynjell-Rahkola, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Barman, Emelie
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Peplinski, Adam
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Hanifi, Ardeshir
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. Swedish Defence Research Agency, FOI.
    Henningson, Dan S.
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    On the stability of flat plate boundary layers subject to localized suction2015Report (Other academic)
    Abstract [en]

    The stability of the Blasius boundary layer subject to localized suction is revisited. Using tools of global stability analysis, the leading direct and adjoint eigenpairs are determined, and novel insight into the sensitivity and receptivity of the flow is obtained. The problem is addressed through high-order spectral element simulations, which enables the inclusion of a suction pipe into the domain. Due to this, a detailed investigation of the connection between the pipe flow and the boundary layer flow is possible. For all cases investigated, the former always turns out to transition for a lower Reynolds number and suction rate than the latter, and the transition scenario is found to be due to a global instability originating inside a separation bubble at the pipe inlet. Identification of such regions, provides information that is valuable in further development of algorithms for laminar flow control.

  • 40.
    Brynjell-Rahkola, Mattias
    et al.
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Shahriari, Nima
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Schlatter, Philipp
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Hanifi, Ardeshir
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control. Swedish Defence Research Agency, FOI.
    Henningson, Dan S.
    KTH, School of Engineering Sciences (SCI), Mechanics, Stability, Transition and Control.
    Onset of global instability behind distributed surface roughness in a Falkner–Skan–Cooke boundary layer2015Report (Other academic)
    Abstract [en]

    A three-dimensional linear global stability analysis of a Falkner–Skan–Cooke boundary layer with distributed three-dimensional surface roughness is performed. The Falkner–Skan–Cooke boundary layer models the flow over swept airplane wings, and investigation of the critical roughness size for which a global instability emerges is thus of great importance within aeronautical applications. The study considers high-order direct numerical simulations and shows that such a critical roughness height exists for the Falkner–Skan–Cooke boundary layer. The roughness Reynolds number and roughness element aspect ratio for which this happens is comparable to the transition data reported in the literature for two-dimensional boundary layers. This demonstrates the importance of the local flow conditions in the vicinity of the roughness for triggering a global instability, although the resulting breakdown scenario is completely different from that of two-dimensional boundary layers. This breakdown scenario is studied in detail, and a global energy analysis is used to reveal the structures and mechanisms responsible for production and dissipation of perturbation energy.

  • 41.
    Bylander, Lars
    et al.
    KTH, Superseded Departments, Alfvén Laboratory.
    Carlström, Ola
    KTH, Superseded Departments, Alfvén Laboratory.
    Christenson, Sverker
    KTH, Superseded Departments, Alfvén Laboratory.
    Olsson, Göran
    KTH, Superseded Departments, Alfvén Laboratory.
    SCALE: A Scaleable Wire Boom System2002In: Smaller Satellites: Bigger Business? Concepts, Applications and Markets for Micro/Nanosatellites in a New Information World / [ed] M. Rycroft, N. Crosby, Springer Netherlands, 2002, p. 355-356Conference paper (Other academic)
    Abstract [en]

    The SCALE wire boom is a compact wire boom unit designed mainly for scientific spin-stabilized satellites. The boom unit provides storage and deployment of a wire boom (length 5–50 m) and a probe (diameter up to about 100 mm). The wire is both a boom and a supplier of the electrical connections between the probe at the end of the wire and the experiment unit in the spacecraft body. The SCALE wire boom is unique because its volume and weight are scaleable with respect to the required boom length and probe diameter.

  • 42.
    Bérard, Adrien
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Cavagna, L.
    Da Ronch, A.
    Riccobene, L.
    Ricci, S.
    Isikveren, A. T.
    Development and validation of a next-generation conceptual aero-structural sizing suite2008In: ICAS Secr. - Int. Counc. Aeronaut. Sci. ICAS, 2008, p. 1718-1727Conference paper (Refereed)
    Abstract [en]

    An overview of a novel variable-fidelity aerostructural computational suite targeted for prediction at the conceptual design phase is presented herein. The computational suite consists of two primary modules known as CADac (Computer Aided Design Aircraft) and NeoCASS (Next generation Conceptual Aero-Structural Sizing Suite). The methodology is based upon the integration of geometry construction, aerodynamic and structural analysis codes that combine depictive, computational, analytical, and semiempirical methods, validated in an aircraft design environment. The aerodynamics sub-space is analyzed using methods based upon a Vortex-Lattice Method used to examine large structural deformations, a Doublet Lattice Method in order to predict flutter boundaries in the subsonic speed regime, and, an Euler based method to cater for identification of flutter points in the transonic regime. A quasi-analytical method that provides accurate weights estimation and refined prediction of airframe moments of inertia data has also been introduced, thus facilitating a more comprehensive investigation of the quasi-static aeroelastic problem. To illustrate the new computational system capabilities, the methodology was applied to a complete flexible structural model of the B747-100 transport aircraft. The quasianalytical weight prediction of the NeoCASS suite was found to generate an accuracy of less than 0.5% error compared to published results.

  • 43.
    Böhme, Vilhelm
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    Boundary Layer Ingestion: EN KONCEPTSTUDIE2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The inhabitants of the earth are facing a global crisis unless the amount ofgreenhouse gases in the atmosphere is reduced to sustainable levels. In anincreasingly globalized world the aircraft industry contributes to an increasinglyamount of emissions that will only increase further if no drastic measures are taken.

    This bachelor thesis aims to study the fuel reduction that in ideal cases can beobtained by utilizing the so-called distributed propulsion configuration. This meansthat a series of electrically driven propellers are placed at the trailing edge of the wingwith purpose to fill the arisen wake behind the wing. The method is well establishedin the marine technology and is referred as the Boundary Layer Ingestion. The resultin the paper is derived from mathematical models and existing data from a Cessna172 aircraft.

    A possible fuel reduction of 11% is derived for a completely idealized situation whichis considered as a very good result which indicates that the BLI technology is worthstudying more closely and develop further.

  • 44.
    Cagatay, Daniel
    KTH, School of Engineering Sciences (SCI).
    Bladelementsanalys – Propeller2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Programmet som skapats ger generella approximationer över hur en flygplanspropeller skall dimensioneras. Det kan uppstå skillnader mellan det praktiska och teoretiska värdena hos propellern. Den vingprofil som dimensionerats är FX67-K-170. Ett optimalt tillstånd har beräknats för denna propeller. Propellerverkningsgraden kan vara så högt som 91 % med en relativ hastighet mellan vind och farkost på 86 m/s och med ett varvtal på 1200 rpm. Avanceringstalet beräknas då till 1,44. Torderingen är som störst vid början av den verkande delen av propellern med en pitchvinkel på 92 grader och ut på spetsen, 31 grader.

  • 45.
    Callbo, Simon
    et al.
    KTH, School of Engineering Sciences (SCI).
    Gottfarb-Bart, Samuel
    KTH, School of Engineering Sciences (SCI).
    Flygteknik: Konceptstudie av ett obemannat flygplan2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Unmanned aerial vehicles (UAV’s) are nowadays greatly appreciated. The advantage over manned airplanes are great since UAV’s can be much smaller and therefore lighter. The goal of this project is to evaluate the performance of an environmentally friendly UAV using only lithium-ion batteries. This in doing monitoring of agriculture or road traffic situations for example.

    In order to determine every parameter of the airplane the electric motor from Sineton and inspiration from other small airplanes composed the starting point. Some important specifications were a maximum weight of 25 kg, a cruise time of at least three hours and a cruise speed of at least 100 km/h.

    In order to reach these goals and determine the parameters of the airplane, the literature General Aviation Aircraft Design: Applied Methods and Procedures by Gudmundsson and the software Matlab were used. This literature contain detailed sections that process every aspect of an airplane. By using this literature, the choice for instance fell upon using a four-bladed propeller in order to minimize the diameter and a semi-tapered wing with an airfoil from NACA. The wing and the tail were also analyzed in the software XFLR5. When all the parameters of the airplane started to take shape, evaluations were made in order to secure adequate performance regarding take-off, climb, stability and landing. 

    The choice of material and power plant are the ones that affect the amount of CO2 emission the most. Since carbon fiber has a higher yield strength and a much lower density, the construction doesn’t need as much material. This some what negates the fact that carbon fiber is much more expensive than aluminium. Besides a lighter airplane requires less energy in use. Concerning the source of energy, lithium-ion batteries does add to CO2 emission in its manufacturing state. In this case it will take around 200 hours of use before the emission from e.g. gasoline would be have to become larger than the initial emission of the manufacturing of the batteries. With this said we consider the use of both carbon fiber and lithium-ion batteries the right choice concerning the environmental aspect for an airplane like this.

  • 46.
    Carlsson, Martin
    KTH, Superseded Departments, Aeronautical and Vehicle Engineering.
    Design and Testing of Flexible Aircraft Structures2004Doctoral thesis, comprehensive summary (Other scientific)
    Abstract [en]

    Methods for structural design, control, and testing offlexible aircraft structures are considered. Focus is onnonconventional aircraft con- figurations and control concepts.The interaction between analysis and testing is a central topicand all studies include validation testing and comparisonbetween computational and experimental results.

    The first part of the thesis is concerned with the designand testing of an aeroelastic wind-tunnel model representing aBlended Wing Body (BWB) aircraft. The investigations show thata somewhat simplified wind-tunnel model design concept isuseful and efficient for the type of investigations considered.Also, the studies indicate that well established numericaltools are capable of predicting the aeroelastic behavior of theBWB aircraft with reasonable accuracy. Accurate prediction ofthe control surface aerodynamics is however found to bedifficult.

    A new aerodynamic boundary element method for aeroelastictimedomain simulations and its experimental validation arepresented. The properties of the method are compared totraditional methods as well as to experimental results. Thestudy indicates that the method is capable of efficient andaccurate aeroelastic simulations.

    Next, a method for tailoring a structure with respect to itsaeroelastic behavior is presented. The method is based onnumerical optimization techniques and developed for efficientdesign of aeroelastic wind-tunnel models with prescribed staticand dynamic aeroelastic properties. Experimental validationshows that the design method is useful in practice and that itprovides a more efficient handling of the dynamic aeroelasticproperties compared to previous methods.

    Finally, the use of multiple control surfaces andaeroelastic effects for efficient roll maneuvering isconsidered. The idea is to design a controller that takesadvantage of the elasticity of the structure for performancebenefits. By use of optimization methods in combination with afairly simple control system, good maneuvering performance isobtained with minimal control effort. Validation testing usinga flexible wind-tunnel model and a real-time control systemshows that the control strategy is successful in practice.Keywords: aeroelasticity, active aeroelastic structures,aeroelastic tailoring, control, structural optimization,wind-tunnel testing.

  • 47.
    Carret, Rémi
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Space Technology.
    Mechanical Assembly Integration and Test of the Qualification Model for the EYESAT Mssion2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In this era of miniaturization and industrial needs for accessing space, nanosatellites are an appropriate and riskless answer. This paper examines the development and the progress of the mechanical assembly, integration and test (AIT) campaign on the CNES CubeSat demonstrator, EYESAT. This student  nanosatellite, designed to observe the zodiacal light in the solar system, is actually in integration and testing phase; and will be launched in 2019. This thesis led the project from the structural and thermal model to the end of the qualification model assembly as well as the beginning of the tests campaign.

  • 48.
    Catalon, Matthieu
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Aerodynamics.
    Attitude Control of the Spacecraft TARANIS:Sun Acquisition Robustness2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This paper deals with the study of the robustness concerning the attitude control of the spacecraft TARANIS regarding disturbances on its sun acquisition sensors. Two kinds of disturbances have been studied: the masking of the sunlight by the dierent spacecraft devices as well as the sunlight reexion on their surface. This study has been performed by doing rst the sensor and observer modeling on a simulator specially designed for the study from the whole spacecraft simulator. Then the modeling of the disturbances has been achieved depending on the characteristics of the sources in terms of size, positioning, roughness and light reection. Finally a set of simulations of the acquisition and survival mode has been executed in order to evaluate the impact of the disturbances on its convergence time. The study shows that the algorithm designed to calculate the spacecraft attitude from the solar sensors data set is robust concerning these disturbances with the actual design of the satellite, but also shows limits concerning the size and positioning of its devices.

  • 49.
    CATY, Fabien
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering.
    DESIGN OF SECONDARY AIR SYSTEM AND THERMAL MODELS FOR TRIPLE SPOOL JET ENGINES2012Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    This master thesis deals with the understanding of the secondary air system of athree spool turbofan. The main purpose is the creation of secondary air systemand thermal models to evaluate the behavior of this kind of engine architectureand estimate the pros and cons in comparison with a typical two spool turbofan. Afinite element model of the secondary air system of the engine has been designedbased on the experience of typical jet engines manufactured by Snecma. Theinner thermodynamic pattern and mass flow rates of the engine were obtained.Some local improvements were then made by making analogies with the enginesmanufactured by Snecma. After having communicated the results to theperformance unit to get updates thermodynamic cycles, a quite reliable model wasobtained and can be used as a reference for further studies of this kind of engineat Snecma.

  • 50.
    CATY, Fabien
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    DESIGN OF SECONDARY AIR SYSTEM AND THERMAL MODELS FOR TRIPLE SPOOL JET ENGINES2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis deals with the understanding of the secondary air system of athree spool turbofan. The main purpose is the creation of secondary air systemand thermal models to evaluate the behavior of this kind of engine architectureand estimate the pros and cons in comparison with a typical two spool turbofan. Afinite element model of the secondary air system of the engine has been designedbased on the experience of typical jet engines manufactured by Snecma. Theinner thermodynamic pattern and mass flow rates of the engine were obtained.Some local improvements were then made by making analogies with the enginesmanufactured by Snecma. After having communicated the results to theperformance unit to get updates thermodynamic cycles, a quite reliable model wasobtained and

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