Search Results

Within the European Integrated Project NACRE (New Aircraft Concept REsearch) led by Airbus, a team of research centers and universities developed a multidisciplinary flying testbed called IEP (Innovative Evaluation Platform). Under the form of a dynamically scaled model of a future civil transport aircraft, its role is to assist engineers during the assessment of flight dynamics characteristics and noise reduction capabilities. After the feasibility study during which potential scientific and economical benefits of such new test facility have been identified, the team decided to design and manufacture the IEP. Because of the dual aspect of the system (it is a flying unmanned aerial vehicle and a test facility), an extensive requirement analysis has been carried out by the partners in order to identify the necessary operational modes and their associated navigation and control strategies.

Avionics systems distributed on AFDX networks are subject to stringent real-time constraints that require the system designer to have techniques and tools to guarantee the worst case traversal time of the network (WCTT) and thus ensure a correct global real-time behavior of the distributed applications/functions. The network calculus is an active research area based on the (min,+) algebra, that has been developed to compute such guaranteed bounds. There already exists several academics implementations but no up to date industrial implementation. To address this need, the PEGASE project gathers academics and industrial partners to provide a high quality, efficient and safe tool for the design of avionic networks using worst case performance guarantees. The PEGASE software is an up-to-date software in the sense that it integrates the latest results of the theories, in tight cooperation with academics researchers.

In this study a comparison is made between results from three Eulerian-based computational methods that predict the ice crystal trajectories and impingement on a NACA-0012 airfoil. The computational methods are being developed within CIRA (Imp2D/3D), ONERA (CEDRE/Spiree) and University of Twente (MooseMBIce). Eulerian models describing ice crystal transport are complex because physical phenomena, like drag force, heat transfer and phase change, depend on the particle's sphericity. Few correlations exist for the drag of non-spherical particles and heat transfer of these particles. The effect or non-spherical particles on the collection efficiency will be shown on a 2D airfoil.

Model Based Safety techniques have been developed for a number of years, though the models have not been customised to help address the safety considerations/ actions at each refinement level. The work performed in the MISSA Project looked at defining the content of “safety models” for each of the refinement levels. A modelling approach has been defined that provides support for the initial functional hazard analysis, then for the systems architectural definition level and finally for the systems implementation level. The Aircraft functional model is used to apportion qualitative and quantitative requirements, the systems architectural level is used to perform a preliminary systems safety analysis to demonstrate that a system architecture can satisfy qualitative and quantitative requirements.

Icing is a major hazard for aviation safety. Over the last decades an additional risk has been identified when flying in clouds with high concentrations of ice-crystals where ice accretion may occur on warm parts of the engine core, resulting in engine incidents such as loss of engine thrust, strong vibrations, blade damage, or even the inability to restart engines. Performing physical engine tests in icing wind tunnels is extremely challenging, therefore, the need for numerical simulation tools able to accurately predict ICI (Ice Crystal Icing) is urgent and paramount for the aeronautics industry, especially regarding the development of new generation engines (UHBR = Ultra High Bypass Ratio, CROR = Counter rotating Open Rotor, ATP = Advanced Turboprop) for which analysis methods largely based on previous engines experience may be less and less applicable. The European research project MUSIC-haic has been conceived to fill this gap and has started in September 2018.

The present paper deals with the accretion of supercooled large droplets (SLD) at high velocity on wall. A visualization technique of the accretion of ice is used to measure and characterize the thickness of ice during the accretion phenomenon. Influences of air velocity, air temperature, drop size, impact angle and altitude were studied. The experiments are conducted in the ONERA icing wind tunnel, which allows to reach regimes close to realistic conditions for aircrafts (i.e. high velocity: → 190 m/s and altitude: → 11 500 m).

This paper proposes an experimental investigation of fast impinging large droplets in non-icing conditions. Two main aspects of the impact event are analyzed and discussed: the impact dynamics as a function of the surface nature and the deposition rate of the liquid on the impingement surface for various conditions. The data has been recorded and characterized at ambient pressure and a temperature of the air between 5 and 10°C using a vertical wind/droplet tunnel. To avoid the droplets evaporation the relative humidity was controlled. The morphology of impact was studied by backlighted imagery and quantitative results were obtained by image analysis. The deposition rate was obtained weighting the water accumulated on the impingement plate. Examination of splashing events images obtained on a clean surface and on blotter paper shows important differences in terms of secondary drop generation.

Recent aircraft incidents and accidents have highlighted the existence of icing cloud characteristics beyond the actual certification envelope defined by the JAR/FAR Appendix C, which accounts for an icing envelope comprising water droplets up to a diameter of 50 μm. The main concern is the presence of SLD (Supercooled Large Droplets), with droplet diameters well beyond 50 microns. In a previous European-funded project, EURICE, in-flight icing conditions and theoretical studies were performed to demonstrate the existence of SLD and to help characterize SLD clouds. Within the EXTICE project the problem of SLD simulation is addressed with both numerical and experimental tools is being addressed. In this paper the objectives and main achievements of the EXTICE project will be described.

The Phylog project aims at offering a model-based software-aided certification framework for aeronautical systems based on multi/many-core architectures. Certifying such platforms will entail fulfilling the high level objectives of the MCP-CRI / CAST-32A position paper. Among those, two types of analysis are required: interference and safety analyses. Because of the large size of the platforms and their complexity, those analyses can lead to combinatorial explosion and to some misinterpretation. To tackle these issues, we explore a service-based modelling approach that leads to a simplification of the analyses and to the highlighting of salient properties, making the adaptation of the certification argumentation efficient.

The seventh European Framework Program (FP7) “Personal Plane” project (PPlane) aims at developing system ideas to enable personal air transport in the long term (2030 and beyond). Such a system will avoid the ever increasing congestion on European roads and offer an alternative to the current conventional transport system across Europe, in particular in those states that still have poor highway and railway networks. The preliminary assumption made in the PPlane project is that automatisms should be developed to enable a “regular Joe” to use a personal aircraft, in various weather conditions, without any command and control difficulties, using a “push button” navigation interface. An on-board automatic system will take care of the complex issues of integration into the airspace (other sky users, class of airspace, Special Use Airspace…), navigation and emergency management.

This paper describes the new analysis software for the contamination modelling and outgassing / vent analysis, which has been developed under ESTEC contract by HTS and ONERA. A major part of the software enhancements have been dedicated to the improvement of the algorithms describing the physical processes involved in outgassing and contamination of species in orbit conditions. However, this paper concentrates on additional aspects of the new software tool, which are of interest for space environment analysis software development in general and the thermal analysis community in particular: The use of commercial software packages for the generation of the discrete model geometry and result visualisation. The interfacing possibilities of the software tool with thermal analysis tools.