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Ayadi N.,University of Sfax | Morette N.,PRISME | Novales C.,PRISME | Poisson G.,PRISME | Derbel N.,University of Sfax
Journal of Engineering Science and Technology Review | Year: 2016

In this paper, we aim developing the issue of mobile robot's localization in a known environment. The robot's model and map parameters are initially analyzed and defined. A generic architecture of the system is then presented. The localization algorithm is developed based on the robot's model and data obtained from exteroceptive sensors. A step of optimisation using the Levenberg Marquardt algorithm is then followed. Thereafter, simulation results are described to show the performance of the proposed algorithm. We followed step by step obtained results. Several improvements have been introduced to the algorithm to correct the location process of the mobile robot. Experimental results show that the robot can be tracked with a high accuracy which reflects the efficiency and the reliability of the localization method.

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.

Gascoin N.,PRISME | Fau G.,PRISME | Gillard P.,PRISME | Kuhn M.,German Aerospace Center | And 2 more authors.
Journal of Porous Media | Year: 2012

The thermal load protection of hypersonic and space vehicle structures can be achieved by either passive or active methods, such as ablative materials or active cooling. For the latter, porous Ceramic Matrix Composite media offer a possibility to exploit thermal protection by means of transpiration cooling. One of the related key issues is the estimation of permeability parameters such as Darcy's and Forchheimer's terms. The present paper aims at proposing an analytical and applied comparison of two determination methods (one based on the International Standard Organisation (ISO) norm 4022 and one derived for compressible flows, the so-called P2 method). To apply these mathematically equivalent laws, a cross verification and validation has been carried out on two different test rigs with different porous media (metallic and composite) with a range of Darcian permeability varying from 1017 m2 to 1011 m2. The French PRISME laboratory test bench has a higher accuracy for thin samples (under 3 mm), while the German Aerospace Center (DLR) rig is more adapted to thick samples (over 3 mm). The results are judged to be satisfactory (discrepancy around 14% for reference samples). The methods used to post-process the data can generate discrepancies up to a factor of 2 for a given set of experimental data. © 2012 by Begell House, Inc.

Gascoin N.,PRISME
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.

Rivas Caicedo M.A.,Grenoble Institute of Technology | Witrant E.,Grenoble Institute of Technology | Sename O.,Grenoble Institute of Technology | Higelin P.,PRISME
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 | Gillard P.,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.

Gascoin N.,PRISME | Abraham G.,PRISME | Gillard P.,PRISME
Journal of Analytical and Applied Pyrolysis | Year: 2010

Large heat load are encountered in hypersonic flight applications due to the high vehicle speed (over Mach 5, i.e. 5000 km h-1) and to the combustion heat release. If passive and ablative protections are a way to ensure the thermal management, the regenerative cooling is probably the most efficient one to enable the structures withstanding (notably for reusable structures). The present study is a part of COMPARER project (COntrol and Measure of PArameters in a REacting stReam) which aims at investigating the highly coupled phenomenon (heat and mass transfers, pyrolysis, combustion) in a cooling channel surrounding a SCRamjet combustion chamber and at proposing some parameters to enable the control of such a complex technology. In this paper, we present the comparative numerical pyrolysis study of some selected synthetic and jet fuels (heptane, decane, dodecane, kerosene surrogate). The fluid pyrolysis has been studied experimentally and the results of RESPIRE numerical simulation under lab and in-flight conditions are given with validation to provide a deep understanding of phenomenon. The impact of the density, of the critical parameters, of the viscosity and of the chemistry is investigated to analyze their effect on the cooling efficiency of the engine. That also enables to estimate properties which the best cooling fuel should have. Furthermore, a combustion study is conducted because the cooling fuel is the one that ensure the thrust. The RESPIRE code enables to conduct both coupled pyrolysis and combustion studies. A first approach of the dynamic regeneratively cooled SCRamjet is provided to get a large vision of the fuel nature impact on the system. © 2010 Elsevier B.V. All rights reserved.

Gascoin N.,PRISME | Fau G.,PRISME | Gillard P.,PRISME
17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011 | Year: 2011

The active cooling of aerospace structures is expected by use of porous material such as Ceramic Matrix Composite. This technology involves a coolant flow through the porosity to enhance the heat transfers. It requires characterizing the permeability to predict its efficiency. The Darcy's and Forchheimer's terms are used in Computational Fluid Dynamics codes to simulate tests of cooling. These parameters are generally deduced experimentally from relationship between the mass flow rate and the pressure drop through the porous media. This paper presents a novel approach taking advantage of well known flow behaviour in chemical reactor engineering. The residence time distribution is analyzed thanks to tracer injection and to associated experimental measures of Infra-Red signal. The IR peak characteristics (height, width, surface, rising and falling gradients) and time delays are analyzed and correlated to physical parameters (mass flow rate, injected mass of tracer, nature of fluids). The peak height and surface and the rising gradient vary linearly in the same sense as the injected tracer mass while the falling gradient varies in the opposite sense. Both gradients decrease with a mass flow rate increase. The time delay between injection and detection of the tracer is quite constant except when changing the fluid nature. A design of experiments allowed estimating quantitatively the influence of each physical parameter on the optical one of the IR signal. Thanks to this first understanding, the Darcy's permeability is linked to the observed IR signal to try providing first relationship to be used later in the opposite to estimate the Darcian term on the basis of IR signal. A linear regression is proposed between this permeation term and the peak width which is judged to be the most relevant parameter. Finally, an analytical approach is developed to fit ordinary differential equation to IR peak measure and to correlate the parameters of the law to the Darcy's permeability. Several laws (linear, logarithmic and power) are proposed depending on the parameter but the linear regression involving the coefficient noted 1 b is the most promising. © 2011 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

Gascoin N.,PRISME | Abraham G.,PRISME | Gillard P.,PRISME
17th AIAA International Space Planes and Hypersonic Systems and Technologies Conference 2011 | Year: 2011

Fuel pyrolysis is studied for its endothermic effect which can be used in regenerative cooling technique to ensure the thermal withstanding of hypersonic vehicles and structures. The thermal decomposition is mainly driven by the temperature, the residence time and the pressure, in this order of importance. Among the production of pyrolysis species, a coke formation can be noticed. This carbon deposit can impact on heat and mass transfer involved in the system because of thermal insulation and of flow cross-section reduction. Furthermore, this carbon deposit modifies the catalytic effect of the reactor because it limits the contact between the reactive flow and the reactor material. The numerical study presented in this paper uses the RESPIRE code to compute successive test cases in order to understand the complex and coupled phenomena involved in the process. Two experiments with stainless steel and titanium reactors are considered as reference. They are reproduced numerically. Then, the case related to stainless steel reactor is computed again with the material properties of titanium to observe the pure effect of properties modifications (which is not easily feasible experimentally). No significant change is observed, which demonstrates that both reactor materials are equivalent physically. Then, the coking rate is computed on the basis of analytical laws derived from past and published experiments. Its thermal insulation effect is observed in the wall of the reactor (artificially no reduction of the crosssection is considered to split the thermal and hydraulic phenomena). Less than 0.2 K of discrepancy is observed. This shows that the conduction effect on the process is negligible. The jamming up of the reactor which is observed experimentally is confirmed numerically at the same time because the carbon deposit thickness reaches the value of the reactor inner radius. Finally, the reduction of flow cross-section due to the growth of carbon layer is considered. The changes in terms of Reynolds number, residence time (decreased by a factor 4) and absorbed energy are considered. This last point is found to be responsible of the discrepancies observed experimentally because a reduction by a factor 3 can be found on this energy. © 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.

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