Aerospace

17 pages, 6588 KiB

Open AccessArticle

Fabrication and Testing of the Cold Gas Propulsion System Flight Unit for the Adelis-SAMSON Nano-Satellites

by Michael Zaberchik, Dan R. Lev, Eviatar Edlerman and Avner Kaidar

Aerospace 2019, 6(8), 91; https://doi.org/10.3390/aerospace6080091 - 19 Aug 2019

Cited by 9 | Viewed by 10313

Adelis-SAMSON is a nano-satellite mission aimed at performing geo-location of target signals on Earth using a tight three-satellite formation in space. To maintain formation, each nano-satellite is equipped with a cold gas propulsion system. The design, qualification, and integration of the Adelis-SAMSON nano-satellite [...] Read more.

Adelis-SAMSON is a nano-satellite mission aimed at performing geo-location of target signals on Earth using a tight three-satellite formation in space. To maintain formation, each nano-satellite is equipped with a cold gas propulsion system. The design, qualification, and integration of the Adelis-SAMSON nano-satellite propulsion system is presented in this paper. The cold gas propulsion system mass is approximately 2 kg, takes a volume of 2U, and generates a thrust of 80 mN from four thrusters using krypton as a propellant. We first present the propulsion system requirements and corresponding system configuration conceived to meet the mission requirements. Subsequently, we present the system architecture while listing all the components. We overview the particular role and qualification process of four of the propulsion system’s components: the propellant tank, thruster assembly, pressure regulators, and fill and vent valve. We detail the tests performed on each component, such as proof pressure tests, vibration tests, and external leak tests. Finally, we present the propulsion system level tests before delivery for satellite integration and discuss the propulsion system’s concept of operations. Full article

(This article belongs to the Special Issue Micro-Propulsion Systems and Components for Small Spacecraft—Current Trends, Innovations and Challenges)

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19 pages, 9149 KiB

Open AccessArticle

Simplified 2D Skin Lattice Models for Multi-Axial Camber Morphing Wing Aircraft

by Bashir Alsaidi, Woong Yeol Joe and Muhammad Akbar

Aerospace 2019, 6(8), 90; https://doi.org/10.3390/aerospace6080090 - 13 Aug 2019

Cited by 3 | Viewed by 6850

Abstract

Conventional fixed wing aircraft require a selection of certain thickness of skin material that guarantees structural strength for aerodynamic loadings in various flight modes. However, skin structures of morphing wings are expected to be flexible as well as stiff to structural and coupled [...] Read more.

Conventional fixed wing aircraft require a selection of certain thickness of skin material that guarantees structural strength for aerodynamic loadings in various flight modes. However, skin structures of morphing wings are expected to be flexible as well as stiff to structural and coupled aerodynamic loadings from geometry change. Many works in the design of skin structures for morphing wings consider only geometric compliance. Among many morphing classifications, we consider camber rate change as airfoil morphing that changes its rate of the airfoil that induces warping, twisting, and bending in multi-axial directions, which makes compliant skin design for morphing a challenging task. It is desired to design a 3D skin structure for a morphing wing; however, it is a computationally challenging task in the design stage to optimize the design parameters. Therefore, it is of interest to establish the structure design process in rapid approaches. As a first step, the main theme of this study is to numerically validate and suggest simplified 2D plate models that fully represents multi-axial 3D camber morphing. In addition to that, the authors show the usage of lattice structures for the 2D plate models’ skin that will lead to on-demand design of advanced structure through the modification of selected structure. Full article

(This article belongs to the Special Issue Adaptive/Smart Structures and Multifunctional Materials in Aerospace)

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15 pages, 7114 KiB

Open AccessArticle

Design and Testing of a Paraffin-Based 1000 N HRE Breadboard

by Francesco Battista, Daniele Cardillo, Manrico Fragiacomo, Giuseppe Daniele Di Martino, Stefano Mungiguerra and Raffaele Savino

Aerospace 2019, 6(8), 89; https://doi.org/10.3390/aerospace6080089 - 12 Aug 2019

Cited by 15 | Viewed by 4795

Abstract

The paper presents some relevant achievements in hybrid rocket propulsion carried out by the Italian Aerospace Research Centre. On the basis of the experimental results obtained on a 200 N thrust class engine, a 1000 N class breadboard, fed with gaseous oxygen coupled [...] Read more.

The paper presents some relevant achievements in hybrid rocket propulsion carried out by the Italian Aerospace Research Centre. On the basis of the experimental results obtained on a 200 N thrust class engine, a 1000 N class breadboard, fed with gaseous oxygen coupled with a paraffin-based fuel grain, was designed and experimentally tested in different conditions. The breadboard exhibited a stable combustion in all the firing test conditions; the testing campaign allowed the acquisition of different experimental data, as pre and post-combustion chamber pressure, throat material temperature, pre-combustion chamber temperature. The new breadboard was characterized by higher measured regression rate values with respect to corresponding data obtained with the smaller scale one, highlighting that the oxidizer mass flux is not the only operating quantity affecting the fuel consumption behavior, which could be also influenced by scale parameters, such as the grain port diameter, and other operating conditions, such as the mixture ratio. Full article

(This article belongs to the Special Issue Advances in Hybrid Rocket Technology and Related Analysis Methodologies)

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26 pages, 4046 KiB

Open AccessArticle

Modeling of High Density Polyethylene Regression Rate in the Simulation of Hybrid Rocket Flowfields

by Daniele Bianchi, Giuseppe Leccese, Francesco Nasuti, Marcello Onofri and Carmine Carmicino

Aerospace 2019, 6(8), 88; https://doi.org/10.3390/aerospace6080088 - 09 Aug 2019

Cited by 15 | Viewed by 4903

Abstract

Numerical analysis of hybrid rocket internal ballistics is carried out with a Reynolds-averaged Navier–Stokes solver integrated with a customized gas–surface interaction wall boundary condition and coupled with a radiation code based on the discrete transfer method. The fuel grain wall boundary condition is [...] Read more.

Numerical analysis of hybrid rocket internal ballistics is carried out with a Reynolds-averaged Navier–Stokes solver integrated with a customized gas–surface interaction wall boundary condition and coupled with a radiation code based on the discrete transfer method. The fuel grain wall boundary condition is based on species, mass, and energy conservation equations coupled with thermal radiation exchange and finite-rate kinetics for fuel pyrolysis modeling. Fuel pyrolysis is governed by the convective and radiative heat flux reaching the surface and by the energy required for the propellant grain to heat up and pyrolyze. Attention is focused here on a set of static firings performed with a lab-scale GOX/HDPE motor working at relatively low oxidizer mass fluxes. A sensitivity analysis was carried out on the literature pyrolysis models for HDPE, to evaluate the possible role of the uncertainty of such models on the actual prediction of the regression rate. A reasonable agreement between the measured and computed averaged regression rate and chamber pressure was obtained, with a noticeable improvement with respect to solutions without including radiative energy exchange. Full article

(This article belongs to the Special Issue Advances in Hybrid Rocket Technology and Related Analysis Methodologies)

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36 pages, 751 KiB

Open AccessArticle

pyCycle: A Tool for Efficient Optimization of Gas Turbine Engine Cycles

by Eric S. Hendricks and Justin S. Gray

Aerospace 2019, 6(8), 87; https://doi.org/10.3390/aerospace6080087 - 08 Aug 2019

Cited by 32 | Viewed by 11195

Abstract

Aviation researchers are increasingly focusing on unconventional vehicle designs with tightly integrated propulsion systems to improve overall aircraft performance and reduce environmental impact. Properly analyzing these types of vehicle and propulsion systems requires multidisciplinary models that include many design variables and physics-based analysis [...] Read more.

Aviation researchers are increasingly focusing on unconventional vehicle designs with tightly integrated propulsion systems to improve overall aircraft performance and reduce environmental impact. Properly analyzing these types of vehicle and propulsion systems requires multidisciplinary models that include many design variables and physics-based analysis tools. This need poses a challenge from a propulsion modeling standpoint because current state-of-the-art thermodynamic cycle analysis tools are not well suited to integration into vehicles level models or to the application of efficient gradient-based optimization techniques that help to counteract the increased computational costs. Therefore, the objective of this research effort was to investigate the development a new thermodynamic cycle analysis code, called pyCycle, to address this limitation and enable design optimization of these new vehicle concepts. This paper documents the development, verification, and application of this code to the design optimization of an advanced turbofan engine. The results of this study show that pyCycle models compute thermodynamic cycle data within 0.03% of an identical Numerical Propulsion System Simulation (NPSS) model. pyCycle also provides more accurate gradient information in three orders of magnitude less computational time by using analytic derivatives. The ability of pyCycle to accurately and efficiently provide this derivative information for gradient-based optimization was found to have a significant benefit on the overall optimization process with wall times at least seven times faster than using finite difference methods around existing tools. The results of this study demonstrate the value of using analytic derivatives for optimization of cycle models, and provide a strong justification for integrating derivatives into other important engineering analyses. Full article

(This article belongs to the Special Issue Multidisciplinary Design Optimization in Aerospace Engineering)

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21 pages, 13056 KiB

Open AccessArticle

Effect of Local Grid Refinement on Performance of Scale-Resolving Models for Simulation of Complex External Flows

by Amne ElCheikh and Michel ElKhoury

Aerospace 2019, 6(8), 86; https://doi.org/10.3390/aerospace6080086 - 06 Aug 2019

Cited by 9 | Viewed by 4410

Abstract

Numerical simulations are crucial for fast and accurate estimations of the flow characteristics in many engineering applications such as atmospheric boundary layers around buildings, external aerodynamics around vehicles, and pollutant dispersion. In the simulation of flow over urban-like obstacles, it is crucial to [...] Read more.

Numerical simulations are crucial for fast and accurate estimations of the flow characteristics in many engineering applications such as atmospheric boundary layers around buildings, external aerodynamics around vehicles, and pollutant dispersion. In the simulation of flow over urban-like obstacles, it is crucial to accurately resolve the flow characteristics with reasonable computational cost. Therefore, Large Eddy Simulations on non-uniform grids are usually employed. However, an undesirable accumulation of energy at grid-refinement interfaces was observed in previous studies using non-uniform grids. This phenomenon induced oscillations in the spanwise velocity component, mainly on fine-to-coarse grid interfaces. In this study, the two challenging test cases of flow over urban-like cubes and flow over a 3-D circular cylinder were simulated using three different scale-resolving turbulence models. Simulations were performed on uniform coarse and fine grids on one hand, and a non-uniform grid on the other, to assess the effect of mesh density and mesh interfaces on the models’ performance. Overall, the proposed One-Equation Scale-Adaptive Simulation (One-Equation SAS) showed the least deviation from the experimental results in both tested cases and on all grid sizes and types when compared to the Shear Stress Transport-Improved Delayed Detached Eddy Simulation (IDDES) and the Algebraic Wall-Modeled Large Eddy Simulation (WMLES). Full article

(This article belongs to the Special Issue Turbulence Simulation and Advanced Theoretical, Experimental, and Computational Method Development Relevant to External Aerodynamics, Separation, and Transitional Flows)

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24 pages, 14709 KiB

Open AccessArticle

Investigation of a Morphing Wing Capable of Airfoil and Span Adjustment Using a Retractable Folding Mechanism

by Amit Geva, Haim Abramovich and Rimon Arieli

Aerospace 2019, 6(8), 85; https://doi.org/10.3390/aerospace6080085 - 31 Jul 2019

Cited by 6 | Viewed by 11230

Abstract

The presented aircraft is capable of alternating between two singular working points by folding the exterior surfaces of the wing underneath the interior surfaces. This allows for a significant change in wingspan, lift surfaces, aspect ratio and airfoil (camber and thickness). The motivation [...] Read more.

The presented aircraft is capable of alternating between two singular working points by folding the exterior surfaces of the wing underneath the interior surfaces. This allows for a significant change in wingspan, lift surfaces, aspect ratio and airfoil (camber and thickness). The motivation for this type of morphing is twofold: The increase in wingspan due to unfolding, results in an increased endurance of the aircraft, while the opposite process, which eliminates the camber of the airfoil and reduces the moment of inertia, is translated into improved manoeuvre capabilities. An analysis was performed to assess the additional endurance gained by the morphing capabilities, factoring in a spectrum of aircraft geometries and flight missions. It was concluded that this morphing concept can, in theory, improve the endurance up to 50% compared to the standard counterparts. The penalty due to the additional weight of the morphing mechanism was factored in, which had an adverse effect on the endurance improvement. The concept also calls for unique airfoil selection process. Selecting a proper airfoil for either working point, results in irregular airfoil geometry upon morphing. The two possibilities were subjected to analysis and wind tunnel testing. Full article

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2 pages, 160 KiB

Open AccessEditorial

Special Issue “8th EASN–CEAS Workshop on Manufacturing for Growth and Innovation”

by Spiros Pantelakis and Konstantinos Kontis

Aerospace 2019, 6(8), 84; https://doi.org/10.3390/aerospace6080084 - 30 Jul 2019

Viewed by 3624

Abstract

This Special Issue contains selected papers from works presented at the 8th EASN–CEAS (European Aeronautics Science Network–Council of European Aerospace Societies) Workshop on Manufacturing for Growth and Innovation, which was held in Glasgow, UK, 4–7 September 2018 [...] Full article

(This article belongs to the Special Issue 8th EASN-CEAS Workshop on Manufacturing for Growth and Innovation)

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Aerospace, Volume 6, Issue 8 (August 2019) – 8 articles

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