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Assessing Advanced Propulsion Systems Using the Impact Monitor Framework
No full textInternational audiencePresented in this paper is the Impact Monitor framework and interactive Dashboard Application (DA) validated through a use case, focusing on investigating the viability and competitiveness of future propulsion architectures for next-generation aircraft concepts. This paper presents a novel collaborative framework for integrated aircraft-level assessments, focusing on secure, remote workflows that protect intellectual property (IP) while enabling comprehensive and automated analyses. The research addresses a key gap in the aerospace domain: the seamless matching and sizing of aircraft engines within an automated workflow that integrates multiple tools and facilitates real-time data exchanges. Specifically, thrust requirements are iteratively shared between aircraft and engine modeling environments for synchronized sizing. Subsequently, the fully defined aircraft data are transferred to other tools for trajectory analysis and emissions and other assessments. The Impact Monitor framework and Dashboard Application demonstrate improved efficiency and data security, promoting effective collaboration across institutions and industry partners
Lien procédé-microstructure-propriétés de composites oxyde/oxyde élaborés par imprégnation de mèches en continu
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La mesure de surface d'onde par Shack-Hartmann
No full textInternational audienceLe Shack-Hartmann est un analyseur largement utilisé en optique adaptative et en métrologie. La mesure repose sur un réseau de microlentilles qui échantillonne la surface d’onde. Les images obtenues permettent d’accéder aux pentes locales, puis, après reconstruction, à la surface d’onde elle-même. Après avoir rappelé son principe, le traitement des données et la reconstruction de la surface d'onde sont abordés en soulignant les avantages et les limites de ce dispositif
A quasi-one-dimensional critical-throat acoustic boundary condition for thermally choked dual-mode ramjet nozzles
No full textThermally choked nozzles, where choking is induced by heat addition rather than a geometrical throat, are a promising solution for dual-mode ramjet transitions to hypersonic speed. Despite their relevance, thermal throat boundary conditions for quasi-onedimensional acoustic modelling are not derived in the state-of-the-art. This study introduces a generalized critical-throat acoustic boundary condition applicable to both geometrically and thermally choked flow configurations. A dedicated one-dimensional linear acoustic solver is formulated to incorporate this condition and is validated against two-dimensional Euler simulations. Particular attention is paid to the impact of entropy and acoustic waves at the critical throat. The results show that the new boundary condition improves the prediction of acoustic reflection, entropy noise production, and transmission coefficients, especially under thermally choked conditions where the commonly used quasi-steady assumption fails. For both the thermal-throat and geometric-throat configurations, the deviation in the acoustic transmission coefficient between the linear acoustic model using the proposed boundary condition and the simulations remains below 2 %, while the deviation in the entropy-noise transmission coefficient remains below 5 %, demonstrating the robustness of the proposed boundary condition
Statistical modelling of the variability of the electron radiation belts for long-term environment specification
No full textInternational audienceSpecifying the electron radiation belts environment is crucial to enable satellite manufacturers and designers to adequately account for its harsh conditions, thereby mitigating risks of unforeseen malfunctions, data loss, and catastrophic failures that can impact spacecraft longevity. We present a novel statistical methodology for developing a radiation belt specification model that provides short- to long-term flux averages for spacecraft mission profiles, accounting for variability due to launch date and space weather/climate conditions. For this, we use an existing reanalysis database constructed using a physics-based radiation belt model and data assimilation. We analyse its flux distributions as well as the space and time correlation functions, and build a representative statistical model of the reanalysis database. Using this statistical representation, we build an innovative specification model prototype that is fast and easy to use, but can effectively be used for mission profiles at all timescales
3D wind measurement with a wind lidar including a quad-Mach-Zehnder interferometer developed for on-board measurement
No full textInternational audienceOn-board 3D wind measurement at all altitudes has numerous aeronautical applications (Gust Load Alleviation, HAPS, etc.) or space (wind measurement with Aeolus, calibration/validation of Aeolus data). This 3D wind measurement is particularly interesting in turbulent wind for several applications such as weather and climate forecasting, planning and safety of aircraft during their flight, transport of aerosols and pollution, monitoring of weather conditions in case disasters, wind power generation, forest fires and volcanic plume movement. (see session A.01.09). The instrument developed for this type of measurement is the direct detection UV lidar which sends a laser pulse into the atmosphere and determines, with a spectral analyzer, the wind projected on the axis of the lidar from the Doppler shift induced by the particles (low altitude) and molecules (high altitudes) of the atmosphere. To measure the radial wind, the quad Mach-Zehnder (QMZ) interferometer is, to our knowledge, the best compromise between precision and robustness [D. Bruneau and J. Pelon, ATM. Measures. Technology. 14 4375-2021 (2021)]. Additionally, such an analyzer can also be used to determine particle backscatter coefficients, extinction coefficient and can be extended with a dedicated channel for aerosol and cloud polarization analysis. This is why, at ONERA, we are developing an all-altitude wind lidar solution based on a QMZ analyzer. The 3D wind is then reconstructed by addressing the lidar axis in several directions and using an algorithm (C. Musso et al., session A.01.09) to recover the 3D wind components from the measured wind projections. This instrument includes several solutions to obtain a vibration-robust version of the different lidar components (analyzer, laser, transmission/reception, scanning system and overall instrument). The QMZ interferometer is a two-wave interferometer that provides four signals of the two-wave interference pattern, in phase quadrature, used to determine the frequency shift of backscattered light energy and derive the radial wind speed. The advantages of the QMZ interferometer, compared to other solutions, are as follows: (1) it is not sensitive to the frequency drift of the laser source, (2) it is not sensitive to the shape of the backscattered spectrum, (3) it gives a small statistical error equal to 2.35 (εvr)ISA where (εvr)ISA is the error obtained for an ideal analyzer, (4) it can include a field compensation design which allows a wide angle of incident field and facilitates their adaptation with an extended wide beam system, and (5) it uses mono-detectors which do not truncate the collected signal (compared to marginal imaging systems). In order to be on-board, two architectures of interferometers robust to vibrations are developed at ONERA: (1) a first based on commercial components and (2) a second monolithic, made up of adhesion of all the optical components. The first version is cheaper and easier to study in depth while the second version is more solid. To obtain architectures insensitive to angular misalignment, both are composed of a single separator and two retroreflective optics. An innovative calibration procedure was developed to determine the exact contrast and phase difference between the four outputs based on the Lissajou curves. The two architectures, their simulated performances and the first experimental results will be presented. In addition to the spectral analyzer, the wind lidar includes several components that must be compacted and reinforced to be able to be used on aircraft. Typically used solid-state UV lasers are very sensitive to vibrations (especially the laser cavity) and their use on board generally requires using a lot of metal to make it insensitive to vibrations, leading to very heavy and expensive solutions. To resolve this problem, we are developing a solution based on a fiber laser which has the advantage of being, in the long term, lighter and more robust to vibrations. The architecture of the system used to address/focus the laser in the probed region and collect the backscattered light from this region is generally designed in a bistatic configuration where the optical axes of the two systems are determined with different optics. However, the transmission and reception must have the same axis, which poses a problem in vibration conditions, for long distance measurements, due to the large lever arm of the two systems. To avoid this problem, we have developed a new monostatic configuration close to that commonly used for heterodyne lidars. To address the beam in different directions, we design a static system comprising several duplicated monostatic transmit/receive instruments. A time multiplexing method is developed to use a shared spectral analyzer to process all axes. The addressed angles were optimized using the 3D wind reconstruction algorithm presented in (C. Musso et al., session A.01.09). The design of all these components will be presented. The project 101101974 – UP Wing is supported by the Clean Aviation Joint Undertaking and its members. Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or Clean Aviation Joint Undertaking. Neither the European Union nor the granting authority can be held responsible for the
Patch antenna enhanced charge-sensitive infrared phototransistors
No full textInternational audienceCharge-sensitive infrared phototransistors (CSIP) constitute an outstanding technology for mid-infrared detection with sensitivities demonstrated at the single photon level. Here, we report on the performances of CSIP detectors operating at a wavelength λ = 8.9 μm that are integrated into double-metal patch antenna resonators. In order to build such devices, we have developed a fabrication protocol that allows accommodating the phototransistor architecture with the double-metal geometry providing very strong electromagnetic field confinement. We observe minimal photon fluxes in the order of 7000 photons/s.μm2 that are 103 smaller with respect to previous realizations of devices with similar absorbing regions in a mesa geometry. This work opens additional perspectives for building ultra-small area devices, as required for single photon counters, while keeping high quantum absorption efficiencies
A methodology to simulate interior and intermediate ballistics with dynamic mesh technique and lumped parameter code
No full textInternational audienceThe aim of this paper is to simulate and study the early moments of the reactive ballistics of a large caliber projectile fired from a gun, combining 0D and 2D axisymmetric Computational Fluid Dynamics (CFD) approaches. First, the methodology is introduced with the development of an interior ballistics (IB) lumped parameter code (LPC), integrating an original image processing method for calculating the specific regression of propellant grains that compose the gun propellant. The ONERA CFD code CEDRE, equipped with a Dynamic Mesh Technique (DMT), is then used in conjunction with the developed LPC to build a dedicated methodology to calculate IB. First results obtained on the AGARD gun and 40 mm gun test cases are in a good agreement with the existing literature. CEDRE is also used to calculate intermediate ballistics (first milliseconds of free flight of the projectile) with a multispecies and reactive approach either starting from the gun muzzle plane or directly following IB. In the latter case, an inverse problem involving a Latin hypercube sampling method is used to find a gun propellant configuration that allows the projectile to reach a given exit velocity and base pressure when IB ends. The methodology developed in this work makes it possible to study the flame front of the intermediate flash and depressurization that occurs in a base bleed (BB) channel at the gun muzzle. Average pressure variations in the BB channel during depressurization are in good agreement with literature
Unterminated Thevenin black box modeling of a DC/3AC converter for aerospace applications
No full textInternational audienceThis article describes a Thevenin black-box modeling method for a converter in the context of a power architecture used for aeronautical applications. It focuses on a non-intrusive procedure based on frequency-domain measurement of the elementary and common-mode currents across the converter, as well as measurement of the impedances of the power architecture equipment. It demonstrates the use of a minimization algorithm to reconstruct the phases of elementary currents not directly accessible by measurement, and the validity of this method. Finally, the model is validated by comparing simulation and measurement, in particular the unterminated aspect of the model</div