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  Subjects -> AERONAUTICS AND SPACE FLIGHT (Total: 123 journals)
Showing 1 - 30 of 30 Journals sorted alphabetically
Acta Astronautica     Hybrid Journal   (Followers: 496)
Advances in Aerospace Engineering     Open Access   (Followers: 70)
Advances in Aerospace Science and Technology     Open Access   (Followers: 8)
Advances in Astronautics Science and Technology     Hybrid Journal   (Followers: 1)
Advances in Space Research     Full-text available via subscription   (Followers: 458)
Aeronautical Journal, The     Hybrid Journal   (Followers: 13)
Aerospace     Open Access   (Followers: 60)
Aerospace Medicine and Human Performance     Full-text available via subscription   (Followers: 19)
Aerospace Science and Technology     Hybrid Journal   (Followers: 430)
Aerospace Scientific Journal     Open Access   (Followers: 18)
Aerospace Systems     Hybrid Journal   (Followers: 6)
Aerospace technic and technology     Open Access   (Followers: 3)
Aerotecnica Missili & Spazio : Journal of Aerospace Science, Technologies & Systems     Hybrid Journal   (Followers: 4)
AIAA Journal     Hybrid Journal   (Followers: 1196)
Air Force Magazine     Full-text available via subscription   (Followers: 10)
Air Medical Journal     Hybrid Journal   (Followers: 8)
Aircraft Engineering and Aerospace Technology     Hybrid Journal   (Followers: 264)
Annual of Navigation     Open Access   (Followers: 22)
Artificial Satellites     Open Access   (Followers: 23)
ASTRA Proceedings     Open Access   (Followers: 3)
Astrodynamics     Hybrid Journal   (Followers: 4)
Aviation     Open Access   (Followers: 17)
Aviation Advances & Maintenance     Open Access   (Followers: 5)
Aviation in Focus - Journal of Aeronautical Sciences     Open Access   (Followers: 10)
Aviation Psychology and Applied Human Factors     Hybrid Journal   (Followers: 27)
Aviation Week     Full-text available via subscription   (Followers: 438)
Canadian Aeronautics and Space Journal     Full-text available via subscription   (Followers: 34)
CEAS Aeronautical Journal     Hybrid Journal   (Followers: 30)
Chinese Journal of Aeronautics     Open Access   (Followers: 21)
Ciencia y Poder Aéreo     Open Access   (Followers: 2)
Civil Aviation High Technologies     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 315)
Cosmic Research     Hybrid Journal   (Followers: 5)
COSPAR Colloquia Series     Full-text available via subscription   (Followers: 11)
Egyptian Journal of Remote Sensing and Space Science     Open Access   (Followers: 24)
Elsevier Astrodynamics Series     Full-text available via subscription   (Followers: 12)
Fatigue of Aircraft Structures     Open Access   (Followers: 15)
Frontiers in Astronomy and Space Sciences     Open Access   (Followers: 12)
Gravitational and Space Research     Open Access  
Gyroscopy and Navigation     Hybrid Journal   (Followers: 260)
IEEE Aerospace and Electronic Systems Magazine     Full-text available via subscription   (Followers: 279)
IEEE Journal on Miniaturization for Air and Space Systems     Hybrid Journal   (Followers: 2)
IEEE Transactions on Aerospace and Electronic Systems     Hybrid Journal   (Followers: 385)
IEEE Transactions on Circuits and Systems I: Regular Papers     Hybrid Journal   (Followers: 39)
International Journal of Aeroacoustics     Hybrid Journal   (Followers: 41)
International Journal of Aerodynamics     Hybrid Journal   (Followers: 37)
International Journal of Aeronautical and Space Sciences     Hybrid Journal   (Followers: 2)
International Journal of Aerospace Engineering     Open Access   (Followers: 82)
International Journal of Aerospace Psychology     Hybrid Journal   (Followers: 23)
International Journal of Aerospace Sciences     Open Access   (Followers: 32)
International Journal of Applied Geospatial Research     Hybrid Journal   (Followers: 7)
International Journal of Aviation Management     Hybrid Journal   (Followers: 9)
International Journal of Aviation Technology, Engineering and Management     Full-text available via subscription   (Followers: 7)
International Journal of Aviation, Aeronautics, and Aerospace     Open Access   (Followers: 5)
International Journal of Crashworthiness     Hybrid Journal   (Followers: 12)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 11)
International Journal of Satellite Communications Policy and Management     Hybrid Journal   (Followers: 13)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 11)
International Journal of Space Structures     Full-text available via subscription   (Followers: 17)
International Journal of Space Technology Management and Innovation     Full-text available via subscription   (Followers: 10)
International Journal of Sustainable Aviation     Hybrid Journal   (Followers: 5)
International Journal of Turbo and Jet-Engines     Hybrid Journal   (Followers: 6)
Investigación Pecuaria     Open Access   (Followers: 3)
Journal of Aerodynamics     Open Access   (Followers: 18)
Journal of Aeronautical Materials     Open Access   (Followers: 9)
Journal of Aeronautics & Aerospace Engineering     Open Access   (Followers: 31)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 69)
Journal of Aerospace Engineering & Technology     Full-text available via subscription   (Followers: 18)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 22)
Journal of Aerospace Information Systems     Hybrid Journal   (Followers: 34)
Journal of Aerospace Technology and Management     Open Access   (Followers: 7)
Journal of Aircraft     Hybrid Journal   (Followers: 337)
Journal of Aircraft and Spacecraft Technology     Open Access   (Followers: 9)
Journal of Airline and Airport Management     Open Access   (Followers: 12)
Journal of Astrobiology & Outreach     Open Access   (Followers: 3)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 11)
Journal of Aviation/Aerospace Education & Research     Open Access   (Followers: 2)
Journal of Engineering and Technological Sciences     Open Access   (Followers: 1)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 205)
Journal of KONBiN     Open Access   (Followers: 3)
Journal of Navigation     Hybrid Journal   (Followers: 280)
Journal of Propulsion and Power     Hybrid Journal   (Followers: 615)
Journal of Space Safety Engineering     Hybrid Journal   (Followers: 8)
Journal of Space Weather and Space Climate     Open Access   (Followers: 27)
Journal of Spacecraft and Rockets     Hybrid Journal   (Followers: 773)
Journal of Spatial Science     Hybrid Journal   (Followers: 3)
Journal of the American Helicopter Society     Full-text available via subscription   (Followers: 8)
Journal of the Astronautical Sciences     Hybrid Journal   (Followers: 9)
Journal of the Australasian Society of Aerospace Medicine     Open Access   (Followers: 1)
Journal of Wind Engineering and Industrial Aerodynamics     Hybrid Journal   (Followers: 17)
Life Sciences in Space Research     Hybrid Journal   (Followers: 4)
MAD - Magazine of Aviation Development     Open Access   (Followers: 2)
Mekanika : Jurnal Teknik Mesin i     Open Access   (Followers: 1)
Microgravity Science and Technology     Hybrid Journal   (Followers: 2)
New Space     Hybrid Journal   (Followers: 6)
Nonlinear Dynamics     Hybrid Journal   (Followers: 20)
npj Microgravity     Open Access   (Followers: 3)
Open Aerospace Engineering Journal     Open Access   (Followers: 1)
Perspectives of Earth and Space Scientists i     Open Access  
Population Space and Place     Hybrid Journal   (Followers: 9)
Problemy Mechatroniki. Uzbrojenie, lotnictwo, inżynieria bezpieczeństwa / Problems of Mechatronics. Armament, Aviation, Safety Engineering     Open Access   (Followers: 3)
Proceedings of the Human Factors and Ergonomics Society Annual Meeting     Hybrid Journal   (Followers: 16)
Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering     Hybrid Journal   (Followers: 46)
Progress in Aerospace Sciences     Full-text available via subscription   (Followers: 81)
Propulsion and Power Research     Open Access   (Followers: 68)
REACH - Reviews in Human Space Exploration     Full-text available via subscription   (Followers: 5)
Research & Reviews : Journal of Space Science & Technology     Full-text available via subscription   (Followers: 17)
RocketSTEM     Free   (Followers: 6)
Russian Aeronautics (Iz VUZ)     Hybrid Journal   (Followers: 24)
Science and Education : Scientific Publication of BMSTU     Open Access   (Followers: 1)
Space and Polity     Hybrid Journal   (Followers: 4)
Space Policy     Hybrid Journal   (Followers: 29)
Space Research Today     Full-text available via subscription   (Followers: 48)
Space Safety Magazine     Free   (Followers: 51)
Space Science International     Open Access   (Followers: 202)
Space Science Reviews     Hybrid Journal   (Followers: 97)
SpaceNews     Free   (Followers: 825)
Spatial Information Research     Hybrid Journal   (Followers: 1)
Technical Soaring     Full-text available via subscription   (Followers: 1)
Transport and Aerospace Engineering     Open Access   (Followers: 1)
Transportmetrica A : Transport Science     Hybrid Journal   (Followers: 9)
Unmanned Systems     Hybrid Journal   (Followers: 5)
Вісник Національного Авіаційного Університету     Open Access   (Followers: 2)

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Journal of Aerospace Technology and Management
Journal Prestige (SJR): 0.204
Citation Impact (citeScore): 1
Number of Followers: 7  

  This is an Open Access Journal Open Access journal
ISSN (Print) 1948-9648 - ISSN (Online) 2175-9146
Published by Departamento de Ciência e Tecnologia Aeroespacial Homepage  [1 journal]
  • Extending Model-Based Systems Engineering into Integrated Platform
           Designed for Civil Aircraft Development

    • Authors: Wenhao Bi, Wenhao Wang, An Zhang, Yunong Wang
      Abstract: With the continuous development and application of modeling technology, civil aircraft designers urgently need to apply model-based systems engineering (MBSE) theory and methods into the field of civil aircraft development. However, the existing modeling tools, which combined with MBSE methodologies, only focus on one particular area, such as requirement modeling, functional modeling and design synthesis. This kind of low coupling design system makes it difficult to link the upstream and downstream designers in the early stage of system development. This paper introduces the MBSE development process of civil aircraft and then establishes an integrated platform composed of six work stations for civil aircraft development based on this process. Commercially available modeling tools, such as IBM Rational DOORS and enterprise architect (EA), are conducted in the platform. The development of flight control system is taken as an example to test the feasibility and efficiency of our integrated platform in logic layer. This platform can complete the activities of aircraft life cycle function analysis, requirement and model management. The loose coupling between the modules and the high cohesive nature allows different system engineers to maintain their design independence and consistency at different stages of development.
      PubDate: 2021-04-28
      Issue No: Vol. 13 (2021)
       
  • Closed Loop Throttle Control of a Liquefying Fuel Hybrid Rocket Motor

    • Authors: Timothy Velthuysen, Michael Brooks, Jean Pitot
      Abstract: The thrust produced by a hybrid rocket motor (HRM) can be controlled by varying the oxidizer flow rate to the combustion chamber. This feature is useful in shaping motor thrust profiles and optimizing a vehicle flight trajectory, but propellant throttling in solid-fuel hybrids is limited to the liquid component only, complicating the control scheme and potentially destabilizing combustion in the motor. While hybrid motor throttling ability remains a subject of considerable interest, there has been little investigation of throttling in motors that use high regression rate, liquefying fuels such as paraffin wax. This article describes the development and implementation of a closed loop thrust control scheme for a laboratory-scale paraffin wax/nitrous oxide HRM using a low-cost ball valve as the controlling hardware element. A model of motor performance is first developed from which proportional-integral-derivative (PID) controller constants are obtained through experimental testing. The control scheme is demonstrated through closed loop hot fire tests of a laboratory-scale motor in which thrust tracks a set-point value with feedback provided through a load cell. Upon reaching the setpoint, the motor remains throttled within ± 2.4% of the maximum thrust of the motor. Constant and ramping thrust profiles are demonstrated.
      PubDate: 2021-04-28
      Issue No: Vol. 13 (2021)
       
  • Investigation of Jet Mixing Characteristics Using Slotted Rectangular Tabs

    • Authors: Anusindhiya Krishnaraj, Vinayagamurthy Ganesan
      Abstract: This article discusses the jet mixing effectiveness of rectangular tab with slots to distort the jet, thereby creating vortices of differing sizes to enhance the mixing. This article numerically investigates the effectiveness of slanted slotted/perforated rectangular tabs with the slot connecting the adjacent faces of the tab to control Mach 0.4 jet. To intensify the jet mixing process, two similar tabs with equal blockage ratio of 7% are placed at diametrically opposite locations of the convergent nozzle exit. The jet flow development in the axial and radial directions of the jet are investigated in detail. To measure the effectiveness of the slotted tabs, the results are compared with the free jet and with the jet operated with solid rectangular tab. The percentage reduction in the core length obtained is 84.1 and 74% for the jet employed with the slotted tab and the solid tab, respectively, when compared with the free jet. The results exhibit that the slotted tab distorts the jet in the near field to a greater extent when compared with the solid rectangular tab.
      PubDate: 2021-03-30
      Issue No: Vol. 13 (2021)
       
  • Computational Aerodynamics Study of Competing Conceptual Designs for
           Advanced Tactical Fighter Aircraft

    • Authors: Waseeq Siddiqui, Hassan Naseer, Syed Mohsin Zahid, Adnan Maqsood, Shuaib Salamat, Rizwan Riaz
      Abstract: Advanced tactical fighter (ATF) configurations are bound to perform high angle of attack (AoA) maneuvers. However, existing conceptual design tools available in aerospace industry are based on empirical or potential flows that cannot predict aerodynamic data in nonlinear regimes. High-fidelity computational fluid dynamics algorithms have to be incorporated during conceptual design phase for better assessment between competing configurations. In this research, steady state aerodynamic analysis is conducted to compare four conceptual designs of advanced tactical fighters through Reynolds-averaged Navier–Stokes (RANS) simulations. Prior to the study, two validation test cases were conducted based on ONERA M6 Wing and benchmark unmanned combat air vehicle (UCAV) design to assess the computational setup for the problem. Pressure based solver is used to model the flow field in subsonic, transonic and supersonic regimes at sea level for all four competing designs. The quantitative results include the aerodynamic forces and the longitudinal stability coefficient comparisons among the models and its components. The qualitative analyses include pressure distribution, eddy shedding and behavior of vortices at varying flow angle. Additionally, the empirical estimation for interpolation and post-stall extrapolation are carried out for further flight performance studies.
      PubDate: 2021-03-30
      Issue No: Vol. 13 (2021)
       
  • A Proposal of a Life-Cycle for the Development of Sounding Rockets
           Missions

    • Authors: Felipe da Motta Silva, Leonel Fernando Perondi
      Abstract: Suborbital flight experiments, carried out through sounding rockets, have been employed for scientific and technological research since the beginning of the space age, in the late 1950s. In Brazil, sounding rocket campaigns have been carried out since 1965, when the Centro de Lançamento Barreira do Inferno (CLBI) began its operation, having the Instituto de Aeronáutica e Espaço (IAE)as the primary provider of vehicles. IAE has also provided vehicles for international programs, such as the TEXUS and MASER microgravity programs, implemented by the European Space Agency (ESA), with launching campaigns based in the European territory. To implement each Brazilian mission that uses IAE’s sounding rockets, a set of activities focused on mission objectives is planned and implemented. Although structured and executed quite similarly to a project, such sounding rocket campaigns do not have their complete life-cycle studied and formally described in phases, review meetings, management processes and verification and validation philosophy. In the present work, the attempt has been to characterize a sounding rocket mission as a project and then, based on European Cooperation for Space Standardization (ECSS) standards, propose a reduced life-cycle to develop such projects, tailored to meet Brazilian sounding rocket missions. The proposed life-cycle, adapted to Brazilian sounding rocket missions, is then compared with two other sounding rocket campaigns life-cycles: one from the European Programme for Life and Physical Sciences in Space and the other from the National Aeronautics and Space Administration (NASA) sounding rocket program. The study and availability of a framework for implementing and managing sounding rocket missions will improve the reliability of such endeavors and speed up their organization.
      PubDate: 2021-03-12
      Issue No: Vol. 13 (2021)
       
  • System Analysis and Design of the Geostationary Earth Orbit All-Electric
           Communication Satellites

    • Authors: Parsa Abbasrezaee, Ali Saraaeb, Mehran Mirshams
      Abstract: With the help of gathered data and formulas extracted from a previous conference paper, the all-electric geostationary Earth orbit (GEO) communication satellite statistical design was conducted and further studied with analytic hierarchy process (AHP) and technique for order of preference by similarity to ideal solution (TOPSIS) methods. Moreover, with the help of previously determined system parameters, the orbital ascension, orbital maintenance and deorbiting specifications, calculations and simulations were persuaded. Furthermore, a parametric subsystem design was conducted to test the methods reliability and prove the feasibility of such approach. The parametric subsystem design was used for electrical power subsystem(EPS), attitude determination and control system (ADCS), electric propulsion, telemetry, tracking and control (TT&C) in conceptual subsystem design level, which highly relies on the satellite type and other specifications, were concluded in this paper; other subsystem designs were not of a significant difference to hybrid and chemical satellites. Eventually, the verification of the mentioned subsystems has been evaluated by contrasting the results with the Space mission engineering: the new SMAD, and subsystem design book reference.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Design of Head Pursuit Guidance Law Based on Fractional-Order Sliding Mode
           Theory

    • Authors: Chenqi Zhu
      Abstract: This paper addresses problems on the interception of hypersonic vehicles in near-space. The main contribution is to study a head pursuit guidance law based on fractional-order sliding mode theory and analyze the stability of the guidance law provided. Firstly, the fractional-order differential operator, which has characteristics such as fast convergence and memory, is introduced into the design of sliding mode surface, based on which a head pursuit guidance can be designed to improve the performance of the guidance system. The stability of this guidance law is proved by Lyapunov stability theory. Based on this, a head pursuit guidance law considering autopilot dynamic characteristic is designed and the stability is also analyzed. Finally, numerical simulations are presented and the results verify that the guidance laws designed in this paper can avoid overload saturation at the initial moment of the terminal guidance stage and improve the convergence speed.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Development of a Turbo Electric Distribution System for Remotely Piloted
           Aircraft Systems

    • Authors: Mithun Eqbal, Nuwantha Fernando, Matthew Marino, Graham Wild
      Abstract: Turboelectric distributed propulsion systems are paving the way for more electric aircraft systems (TeDP). This type of system provides a solution for some of the drawbacks of current low-energy-density batteries, which limit the ability of long-endurance electric aircraft. However, turboelectric propulsion requires the use of advanced turboelectric motors, superconductive materials and cryogenic cooling technologies, which are still under development and may be in production in the near future. This paper investigates a turboelectric propulsion system that can be considered an initial step in the production of TeDP in a remotely piloted aircraft system with the use of existing technology. This is achieved by replacing the gear and the starter motor of a turboprop with a high-speed permanent magnet electric machine to generate electrical power and propelling the aircraft through a distributed electric propulsion system. In this theoretical study, an augmentation to Breguet’s range and endurance equation is developed. This study confirmed that the new system is 31% lighter than the turboprop engine. Then the effect of the weight savings is used in the distributed electric propulsion (DEP) aerodynamic studies and found that there is a drastic increase in the range for a TeDP developed with the high-speed machine.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Vertical Wind Profile Modeling at Low Levels Using a Regional Climate
           Model in a Case Study at the Alcântara Launch Center

    • Authors: Cleber Souza Correa, Antonio Paulo de Queiroz, Gerson Camillo
      Abstract: This case study, using a regional climate model (RegCM-4.7) in high horizontal resolution, allowed to obtain information on the intensity of the average vertical wind profile over the Alcântara Launch Center (ALC), Brazil. In the literature, on the wind intensity, the lack of continuous monitoring of the existence of flows in the vertical profile of the wind at heights of 400 to 600 m and the measurement of its magnitude make it possible to have an estimate lower than what can occur in reality at a low level in the region for operational purposes for the rocket launch. Therefore, this works results points to an intraseasonal variability of the wind intensity with maximum winds of the order of 14 to 20 m·s-1 in the core wind intensity at heights of 600 m, corresponding to pressure levels of the order of 930 hPa, in August, September and October 2020. These intensity values should be further studied with the use of observation equipment such as sound detection and ranging (SODAR) in the continuation of this research, in moment future, as well; the global models of reanalysis have low resolution and are not suitable for comparisons.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Comparative Study of Coaxial Main Rotor Aerodynamics in the Hover with the
           Usage of Two Methods of Computational Fluid Dynamics

    • Authors: Sergey Gennadievich Konstantinov, Yuri Mikhailovich Ignatkin, Pavel Viacheslavovich Makeev, Sergey Olegovich Nikitin
      Abstract: The paper is focused on numerical modeling of the aerodynamic characteristics of a full-scale coaxial main rotor in hover. The simulation was performed using two approaches of computational fluid dynamics (CFD): the original free wake model (FWM) developed by the authors and the unsteady Reynolds-averaged Navier–Stokes (URANS) equations method based on the Ansys Fluent software. The structure of the rotor vortex wake, flow images, vorticity and induced velocity fields, total and distributed aerodynamic characteristics of the rotor, including the rotor performance and figure of merit diagrams, have been analyzed. A comparison between FWM/URANS based calculations and calculated/experimental data by other authors has been performed. A satisfactory match of these data confirms reliability of used methods when modeling the aerodynamic characteristics of coaxial rotors. The FMW demonstrates a significant advantage in speed and resources intensity when calculating the total aerodynamic characteristics of a coaxial rotor. The URANS method makes it possible to model with significant accuracy the effects associated with the blade vortex interactions and pressure distribution over the blade surface. Finally, conclusions about most effectiveness of joint application of considered methods in solving complex problems of coaxial rotor aerodynamics has been made.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Financial Analysis of an Illumination Retrofit for Regional Aircraft

    • Authors: Inah de Almeida Bossi Guimarães, Alison de Oliveira Moraes, Domingos Savio Barbosa
      Abstract: The light-emitting diode (LED) is the main lighting solution currently adopted in aircraft cabin lighting. This technology offers high durability, energy efficiency and luminosity, bringing plenty of benefits for being utilized in an aircraft. Despite its high initial price, it has many advantages, and the operational cost is lower than other types of illumination, such as fluorescent lamps. Additionally, LED illumination may improve the flight experience, making it more comfortable and pleasant for the passengers. Aircraft that have fluorescent lamps in their cabin should consider the possibility to make an illumination retrofit to LED lamps, because weight is directly correlated to the fuel consumption and operational costs and the energy economy can bring new improvements to the aircraft. The objective of this work is to evaluate the economic viability of the LED system installation compared with a fluorescent lamps illumination system in a regional aircraft. The study of the data shows that the usage of LED lights could save up to 68% of the energy in a month compared to conventional fluorescent lamps in the ceiling lights and reduce by 38% the monthly operational costs of illumination. The payback period is 4.2 years according to the proposed system.
      PubDate: 2021-03-05
      Issue No: Vol. 13 (2021)
       
  • Modeling and Validation of Passive Rectifier for Airplanes with Variable
           Frequency and Bipolar DC Buses

    • Authors: Lais Abrantes Vitoi, Jose Antenor Pomilio, Danilo Iglesias Brandão
      Abstract: Traditional airplanes with fixed frequency and unipolar DC bus (270 V) commonly use 12-pulse passive rectifiers. The increase of power demand and the concern with aircraft efficiency boost the electrification of airplanes using variable frequency (360-800 Hz) and bipolar DC buses (± 270 V). Thus, this paper analyses the 12-pulse passive rectifiers in this new scenario. It is proposed an accurate model, describing its design, to verify if passive rectifiers are suitable for aircraft application complying with current standards. The analysis of the 12-pulse rectifier is done by an association of two 6-pulse rectifiers and considering both sorts of an input filter, L and LC. The mathematical model is presented and considers typical harmonic components, allowing precise analysis of input current and output voltage. Simulation and experimental results are provided to validate the mathematical model. The paper shows that the 12-pulse passive rectifier is not a viable solution when operating under variable frequency, which was verified by the violation of the electricity quality standards.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Double Layer Material Designed to Reduce Electromagnetic Radiation with
           Carbon Black, Silicon Carbide and Manganese Zinc Ferrite

    • Authors: Gisele Amaral Labatl, Matheus Bispo Carvalho, Nila Cecília Faria Lopes Medeiros, Leonardo Medeiros, Alan Fernando Ney Boss, Guilherme Lenz, Mauricio Baldan
      Abstract: Radar absorbing materials (RAMs) are composites made with a polymeric matrix and an electromagnetic absorbing filler, such as carbon black (CB), silicon carbide (SiC) or manganese zinc ferrite (MnZn). To enhance their performances to attenuate an incident wave through reflection loss (RL), RAMs can be produced in multilayer structures. Usually, the RL analysis is done theoretically and experimentally validated with free space analysis. Here, it was demonstrated that multilayer structure can be designed and easily validated using rectangular waveguide, using a simpler setup and small samples. Three composites were produced using 2 wt% of CB (CB2), 40 wt% of SiC (SiC40) and 60 wt% of MnZn (MnZn60). They were characterized over the Ku-band and used to validate the multilayer structures, that were prepared by simply stacking each material inside the waveguide sample holder. One of the best results was obtained with structure SiC40+CB2 with 5.85 mm thickness, that presented a calculated RL of -21 dB at 17.8 GHz and a measured RL of -36 dB at the same frequency. In conclusion, using rectangular waveguide has been proven to be an easy, cheap, precise and fast approach to validate multilayer structures designs.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Study of Flow Field Inside a Can Combustor for Micro Gas Turbine Engine
           Under Nonreacting Flow Conditions

    • Authors: Kirubakaran Vijayakumar, David Bhatt
      Abstract: Generally, micro gas turbines are in the range of 15 to 300 kW. However, recent applications in unmanned aerial vehicles (UAVs) and polygeneration require a small micro gas turbine. So, here a small swirl combustor designed for micro gas turbine engine of capacity less than 1 kW is analyzed under nonreacting flow conditions. Simulations have been carried out to study the flow field inside the can combustor. Flow field characteristics, like velocity, path lines, turbulent intensity and total pressure loss are studied. The total pressure loss across the combustor is also measured experimentally and compared with that of simulation results. Good agreement is achieved between experimental and numerical results. The combustor total pressure drop was found to be negligible in the range of 0.002 to 0.06% at an inlet velocity ranges from 1.7 to 10.19 m/s. Flow pattern indicates a strong swirling pattern and strong interaction between the secondary air entrainment inside the flame tube.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Determination of Polychloroprene Content in Rubber Blend Containing
           Ethylene Propylene Diene Monomer by Infrared Techniques

    • Authors: Paulo Santos Rigoli, Alexandra Helena de Barros, Rachel Farias Magalhães, Lídia Mattos Silva Murakami, Alexandre Estevão Carrara, Jorge Carlos Narciso Dutra, Elizabeth Costa Mattos, Rita de Cássia Lazzarini Dutra
      Abstract: Ethylene propylene diene monomer rubber is used as flexible thermal protection for rocket engines, as well as in blends with polychloroprene, which can be applied in the aeronautical sector, and with great potential in the defense sector. However, there is not a considerable number of studies considering both polymers as a blend. In general, elastomer content quantification in blends is done by more complex instrumental methods. When performed by Fourier transform-infrared spectroscopy, the conventional transmission mode is used, usually without including the developed methodology error. Therefore, the Fourier transform infrared spectroscopy (FT-IR) methodology is proposed using the universal attenuated total reflection mode, with sample treatment (pyrolysis) to determine polychloroprene content in the mixture with ethylene propylene diene monomer. In accordance with the infrared spectrometer precision limits and rubber blends studies data found in the literature, the methodology error analysis shows a value close to 2%. In addition, it has the advantage of being a less complex methodology. This actual study uses a simple FT-IR analytical tool, scarce, especially for the rubber research community, to determine the content of rubber minor phase within the major phase. It is valuable in weapons reverse engineering, aiming at the knowledge of new thermal protections.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Filtration of UAV Movement Parameters Based on the Received Signal
           Strength Measurement Sensor Networks in the Presence of Anomalous
           Measurements of Unknown Power at the Transmitter

    • Authors: Igor Tovkach, Serhii Zhuk
      Abstract: Methods based on received signal strength measurements (RSS measurements) are used to determine the unmanned aerial vehicle (UAV) location using a wireless sensor network. The UAV transmitter power is usually unknown. In real conditions, it often becomes necessary to consider existence of anomalous measurement results. The reasons for the violation of the measurement process can be: the influence of interference, errors in the identification of signals during primary processing, failures of the equipment and similar. The optimum and quasi-optimal adaptive algorithms of UAV movement parameters filtration based on the RSS-measurement sensor networks in the presence of anomalous measurements at the unknown power of the transmitter are developed. These algorithms are obtained using Bayes’ theorems and the Markov property of a mixed process, including a vector of target movement parameters and a discrete component characterizing the type of measurement. Analysis of developed algorithm performance was carried out by Monte Carlo method on 2D plane. The quasi-optimal adaptive filtering algorithm detects the appearance of anomalous measurements with probabilities close to unity and allows one to eliminate their influence on the accuracy of UAV movement parameters estimation and also to estimate the UAV unknown transmitter power.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Effect of Parameter Variation on the Viscosity of Ethanol Gel Propellants

    • Authors: Chloé Carer, Leonhard Xaver Driever, Stein Köbben, Max Mckenzie, Fredrik Rhenman, Onno Van de Sype, Jesse van der Toorn, Casper van Wezel, Constança Miranda de Andrade Veiga, Aleksandrs Vinarskis, Botchu Vara Siva Jyoti
      Abstract: This research investigated how the variation of temperature and shear rate affects the viscosity of ethanol gel propellants that use methyl cellulose as gellant and, in parts, use boron as energetic additive. Using a rotational viscometer in a cone-and-plate configuration, propellant viscosity data was recorded across a range of temperatures and applied shear rates. The temperature dependence of the viscosity was modelled using an Arrhenius-type equation. For the high shear rates, the data was modelled using the Power Law, Herrschel–Bulkley model, Carreau model, and Cross model. For low shear rates the used model was the rearranged Herrschel–Bulkley model. The temperature investigation suggested that the trend of decreasing viscosity with increasing temperature, predicted by the Arrhenius-type equation, is only applicable until approximately 320 K, after which the gel viscosity increased strongly. At high shear rates, the gel behaved in a shear thinning manner and was modelled most accurately by the Cross model. At low shear rates, the gel was shear thickening up to its elastic limit, which was found to lie at 0.41 s–1.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Using Multiple Deep Neural Networks Platform to Detect Different Types of
           Potential Faults in Unmanned Aerial Vehicles

    • Authors: Ahmad Alos, Zouhair Dahrouj
      Abstract: Many researchers developed new algorithms to predict the faults of unmanned aerial vehicles (UAV). These algorithms detect anomalies in the streamed data of the UAV and label them as potential faults. Most of these algorithms consider neither the complex relationships among the UAV variables nor the temporal patterns of the previous instances, which leaves a potential opportunity for new ideas. A new method for analyzing the relationships and the temporal patterns of every two variables to detect the potentially defected sensors. The proposed method depends on a new platform, which is composed of multiple deep neural networks. The method starts by building and training this platform. The training step requires reshaping the dataset into a set of subdatasets. Each new subdataset is used to train one deep neural network. In the testing phase, the method reads new instances of the UAV testing dataset. The output of the algorithm is the predicted potential faults. The proposed approach is evaluated and compared it with other well-known algorithms. The proposed approach showed promising results in predicting different kinds of faults.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Upper Stage Liquid Propellant Rocket Engine: A Case Analysis

    • Authors: Daniel Soares de Almeida, Emerson Andrade dos Santos, Günter Langel
      Abstract: This paper provides an overview of the design and development process for the L75 liquid propellant rocket engine (LPRE) foreseen as upper stage of a satellite launch vehicle application. Emphasis is put on the choice of available technologies, an adequate operational cycle, and the most suitable propellant combination. Problems encountered during the development and resulting solution approaches are described. Furthermore, a survey of upper stages including their main performance data currently in operation worldwide is presented. Since economical constraints are more important today compared to previous developments schedule and cost figures and their drawbacks are investigated as well. Finally, a summary regarding the development status of the Brazilian L75 engine is reported.
      PubDate: 2021-02-15
      Issue No: Vol. 13 (2021)
       
  • Remotely Piloted Aircraft: Analysis of the Deployment in Aeronautical
           Accident Investigation Bureau

    • Authors: Humberto Dorneles Santa Maria, Rodrigo Franklin Frogeri, Fabricio Pelloso Piurcosky, Liz Áurea Prado
      Abstract: This study analyzed Remotely Piloted Aircraft System (RPAS) deployment in the Regional Services of Aeronautical Accidents Investigation and Prevention (SERIPA – Brazil) as a support tool to investigate aviation accidents. Such review is justified by the acquisition and use of this equipment and new technology by investigators since 2017. Research aim was to analyze the perception of SERIPA investigators regarding the usefulness and ease of use of the RPAS equipment. We applied an adaptation of the Theoretical Model of Technology. Methodologically, the study was characterized as exploratory and carried out through an inductive logic and qualitative approach. A case study has been done with 14 investigators belonging to six Brazilian SERIPA units. In conclusion, the respondents deem the RPAS to be useful for aircraft accident investigation, and the equipment is of easy use. RPAS was observed as a tool capable of replacing manned aircraft in some crash sites. The external variable, i.e. crash site characteristics, emerged as a factor that influences the use of RPAS, as well as the transport of RPAS in commercial aircraft.
      PubDate: 2021-02-10
      Issue No: Vol. 13 (2021)
       
  • A Numerical Approach for Implementing Air Intakes in a Canard Type
           Aircraft for Engine Cooling Purposes

    • Authors: Odenir Almeida, Pedro Correa Souza, Erick Cunha
      Abstract: This work presents selected results of an unconventional aircraft development campaign. Engine installation at the rear part of the fuselage imposed design constraints for air intakes that should be used for cooling purposes. Trial and error flight tests increased the development cost and time which required a more sophisticated analysis through computational fluid dynamics (CFD) techniques and robust semiempirical approach. The carried-out investigation of the air intakes started with an empirical approach from guidelines for designing NACA and scoops. Numerical studies via computational fluid dynamics were performed with the air intakes installed in the aircraft fuselage. An analysis based on the air intake efficiency, drag and the effect of angle of attack are detailed in this work. Different air intakes designs, such as scoops of different shapes, were evaluated seeking for improved air intake efficiency and low drag while providing enough air for cooling the engine compartment. The results showed that the numerical approach used herein decreased the development cost and time of the aircraft, providing a reasonable low-cost approach and leading to a design selection more easily. Based on the current approach the canard airplane geometry was changed to account for the new selected air intake for engine cooling purposes.
      PubDate: 2021-02-10
      Issue No: Vol. 13 (2021)
       
  • The 6,500-H Life Test Results of 30 cm Diameter Ion Thruster

    • Authors: Sun Mingming, Hai Geng, Yi Zheng
      Abstract: The life test of the 30 cm diameter ion thruster developed by the Lanzhou institute of physics began in Apr. 2018 and ended in Jan. 2020, lasting 6,500 h. This paper introduces the results of the 6,500-h life test of the 30 cm diameter ion thruster completed on the ground, including the ground facility for life test, the variations of the thrusters working performance, the times of the breakdown and power restart, and the erosion of the key components. The results show that the performance parameters, such as thrust, specific impulse and efficiency, do not change obviously during the test and magnetic field of the discharge chamber has no change. With the increase of test time, breakdown times increased significantly, whereas the power restart time decreased correspondingly. The diameter of the cathode orifice decreases gradually and there is a blockage risk of orifice. However, the diameter of the keeper orifice increases and presents an inverted cone erosion pattern. The diameter of the decelerator grid aperture expanded from 1.6 to 1.8 mm from 0 to 1,000 h and slightly enlarged after that. The aperture diameter of the accelerator grid presented linear enlargement but the pits-and-grooves erosion is obvious.
      PubDate: 2021-02-10
      Issue No: Vol. 13 (2021)
       
  • Investigations on Complex Acoustic Modes of Rocket Engines Combustion
           Chambers for Damping Allocation

    • Authors: Gustavo Paulinelli Guimarães, Rogério Pirk, Carlos D'Andrade Souto, Luiz Carlos Sandoval Góes
      Abstract: Combustion instability can severely impair the operation of many kinds of combustion engines. Acoustic resonators are widely used to suppress the pressure oscillations caused by the coupling between the combustion process and the combustion chamber acoustic modes. Combustion chambers with subsonic flow in its inlets and outlets, like gas turbine combustors, exhibit some acoustical damping due to the presence of openings. In such chambers, the acoustic modes are complex. In a complex mode, the antinode regions can be shifted from its position in the corresponding real mode. In this work an experimental acoustic modal analysis of a cavity with an opening was performed. Acoustic frequency response functions were obtained by using a volume acceleration source, a microphone and a data acquisition system. The PolyMAX algorithm was used to estimate longitudinal modes in its real and complex versions. A comparison was performed and the results show that, for some modes, the antinode region placement could change reasonably. This suggests that the use of complex modes for location of antinode regions provides more accurate results and consequently could be a better way to identify positions, where resonators provide maximum damping in order to minimize combustion instability in subsonic combustion chambers.
      PubDate: 2021-02-04
      Issue No: Vol. 13 (2021)
       
  • Open Science to Knowledge without Borders

    • Authors: Elizabeth Costa Mattos
      PubDate: 2021-02-01
      Issue No: Vol. 13 (2021)
       
 
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