International Journal of Multiphase Flow | Year: 2011
Large heat load are encountered in hypersonic and space flight applications due to the high vehicle speed (over Mach 5, i.e. 5000kmh-1) and to the combustion heat release. If passive and ablative protections are a way to ensure the thermal management, the active cooling is probably the most efficient way to enable the structures withstanding of such large heat load. In some conditions, transpiration cooling will be used. In this paper, the permeation of fuels and other fluids through porous media is studied up to 1150K and 60bars. A dedicated experimental bench has been established to ensure the monitoring of temperature, pressure, mass flow rate and chemical composition (Gas Chromatograph, Mass Spectrometer, Infra Red spectrometer) in stationary and transient conditions. The tests on metallic and composite samples have been conducted with N2, CH4, H2+CH4 mixtures and synthetic fuels (n-C12H26). The pressure losses comparison with the mass flow rate has enabled the determination depending on the temperature of the Darcian permeability, KD the linear contribution, and of the Forchheimer's term, KF the quadratic one. The fuel pyrolysis in such low Reynolds flow has been investigated. The blockage effect due to coking activity has been estimated. © 2010 Elsevier Ltd.
Chetouani A.,PRISME |
Beghdadi A.,Institut Universitaire de France |
Bouzerdoum A.,University of Wollongong |
Deriche M.,King Fahd University of Petroleum and Minerals
2012 3rd International Conference on Image Processing Theory, Tools and Applications, IPTA 2012 | Year: 2012
In this paper, we propose to overcome one of the limitations of No Reference (NR) Image Quality Metrics (IQMs). Indeed, this kind of metrics is generally distortion-based and can be used only for a specific degradation such as ringing, blur or blocking. We propose to detect and identify the type of the degradation contained in the image before quantifying its quality. The degradation type is here identified using a Linear Discriminant Analysis (LDA) classifier. Then, the NR-IQM is selected according to the degradation type. We focus our work on the more common artefacts and degradations: blocking, ringing, blur and noise. The efficiency of the proposed method is evaluated in terms of correct classification across the considered degradations and artefacts. © 2012 IEEE.
Rivas Caicedo M.A.,Grenoble Institute of Technology |
Witrant E.,Grenoble Institute of Technology |
Sename O.,Grenoble Institute of Technology |
Proceedings of the American Control Conference | Year: 2012
A high gain non linear observer is implemented to estimate the enclosed mass in the combustion chamber of a spark ignited engine. The observer uses the cylinder pressure measurement during the compression and combustion strokes to estimate the enclosed mass. An engine model is proposed and used as a virtual engine to build the observer. The model is validated by comparison with real measurements, obtained from experimental tests. The results of the observer are compared with the virtual engine model. © 2012 AACC American Automatic Control Council).
Gascoin N.,PRISME |
41st AIAA Fluid Dynamics Conference and Exhibit | Year: 2011
Hypersonic flight over Mach 5 is expected to be achieved with Supersonic Combustion Ramjet. Due to the high heat load resulting from the flight speed and from the combustion, a cooling system is required to ensure the withstanding of the structure. The regenerative cooling presents the advantage to use the fuel as a coolant, to convert the thermal energy into chemical one by pyrolysing the hydrocarbon fluid, whose process is endothermic. This is also necessary to ensure a good combustion into the chamber because auto-ignition delays lower than 0.1 ms are required. The chemistry is of major impact in such system and it requires using highly detailed kinetic mechanisms. For this purpose, both cooling channel and combustion chamber are studied by coupling the related phenomena involving heat and mass transfer with detailed chemistry (360 species and 2777 reactions). To prepare a future work on engine's control, a Mach 6 flight configuration is chosen to study the impact of fuel mass flow rate on the combustion. A higher mass flow rate is seen to contribute to the higher hot gases temperature and faster stabilization time and auto-ignition delay (or the order of 20 ms and 20 μs respectively). A couple time-temperature is shown in the CC to ensure the flame anchoring. The predominant effect of the combustion on the hot wall temperature (reaching 1800 K) compared to the cooling effect of the fuel (limited to 1500 K) from the other side is demonstrated. Several analytical laws between fuel temperature, mass flow, residence time and wall temperature are proposed to construct a basic model of the system in order to be able developing control strategy of the cooling-combustion coupled system. The time characteristics of the phenomena are determined in case of flow rate change (from 0.1 s to over 1 s). In this case, the combustion is firstly impacted before the fuel decomposition rate and then the heat transfers. A hysteresis is found between two identical values of mass flow after a sudden change because of the heat transfer dynamic. The rate of flow change impacts the time constants of the phenomena. Finally, the combustion mechanism is validated experimentally for kerosene pyrolysis application, which will enable decreasing the computation cost through the reduction of mechanism' size. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
Velazco R.,TIMA |
Mansour W.,TIMA |
Pancher F.,TIMA |
Marques-Costa G.,TIMA |
And 2 more authors.
IEEE Transactions on Nuclear Science | Year: 2012
The single-event upset (SEU) fault tolerance of a benchmark self-converging algorithm is evaluated by fault injection campaigns performed using a devoted test platform. The number of observed errors significantly decreases depending on adopted implementation strategies. © 2012 IEEE.