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Esnault, Olivier. "Sur un modèle de combustion en milieu désordonné". Phd thesis, Poitiers, 2007. http://tel.archives-ouvertes.fr/tel-00258217.
Pełny tekst źródłaBen, Taib Ahmed. "Etude mathématique et numérique d'un modèle de combustion turbulente". Lyon 1, 1993. http://www.theses.fr/1993LYO10245.
Pełny tekst źródłaHillion, Mathieu. "Contrôle de combustion en transitoires des moteurs à combustion interne". Phd thesis, École Nationale Supérieure des Mines de Paris, 2009. http://pastel.archives-ouvertes.fr/pastel-00005749.
Pełny tekst źródłaLoubeau, Vincent. "Sur un modèle de combustion solide-solide à énergie d'activation finie". Bordeaux 1, 1992. http://www.theses.fr/1992BOR10596.
Pełny tekst źródłaMartinot, Stéphane. "Développement d'un modèle de suies pour la modélisation multidimentionnelle des polluants dans les moteurs diesel". INSA de Rouen, 2002. http://www.theses.fr/2002ISAM0009.
Pełny tekst źródłaMillet, Jean-Baptiste. "Modélisation réduite de la combustion homogène Diesel : développement d'un modèle zéro-dimensionnel de combustion HCCI avec cinétique chimique réduite". Paris 6, 2006. http://www.theses.fr/2006PA066500.
Pełny tekst źródłaRehayem, Elias. "Modélisation des turbomachines : Dérivation d’un modèle phénoménologique de combustion pour la simulation de transitoires sur hélicoptères". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC056/document.
Pełny tekst źródłaThis work investigates a unique 0D/1D physical approach for gas turbine combustor modelling. It accounts for fuel evaporation, turbulence, combustion, and allows to represent dilution stages. Detailed pollutants formation models can also be added. The chosen formalism, based on the Bond Graph theory approach, allows to describe systems organised in a series of submodel components such as a series of open volumes forming a flame tube, or a combustor coupled to a compressor and turbine but they can also be combined with control and regulation devices in order to represent a complete rotorcraft. The essence of the PhD strategy is the application of a 0D combustion paradigm, obtained at IFP Energies nouvelles by formal reduction of 3D approaches for gas turbines. More in details, a new combustion model was developed integrating the Coherent Flame Model (CFM) formalism which allows to distinguish between fresh gases and burned gases separating them with a turbulent flame. The flame tube submodel features a physical description of the flame thanks to thorough understanding given by 3D CFD simulation results validated against experimental measurements. More specifically, LES results corresponding to a single phase test rig were analysed in order to characterise premixed turbulent combustion in a swirl burner. Finally, a real turboshaft combustor sector case was studied by means of CFD simulations to investigate the relevance of the 0D/1D flame tube model and to determine modelling strategies for the completion of the new gas turbine system simulation approach
Rego, Rui. "Sur un modèle non linéaire d'interaction entre flamme et acoustique". Poitiers, 2006. http://www.theses.fr/2006POIT2304.
Pełny tekst źródłaPremixed flames may be considered as thin active interfaces, a point of view that we adopt here. Whereas accurate asymptotic expansions methods exist to obtain first-order-in-time Evolution Equations, whenever flow-field accelerations intervene those methods fail to provide an unambiguous answer. Still, suitable designed Evolution Equations that are able to handle with flow accelerations are tailored, based on phenomenological grounds, symmetry arguments, and consistency with known limiting cases. Those describe flame dynamics by a second-order-in-time Evolution Equation, with a geometrical non-linearity stemming from normal (Huygens) propagation, the density change, the overall geometry, and the inertia-induced gravitational forcing, provided that Galilean invariance is fulfilled. This flame EE model is numerically coupled with its self-induced acceleration field, where linear acoustics is shown to prevail on transverse average. The flame-shape evolution is handled via a Fourier pseudo-spectral method, which is checked against flame responses to prescribed accelerations successfully, even in the nonlinear regime. This nonlinear, global, system model is solved for flames in tubes as an example. Follow-on studies are also envisaged
Stefanin, Volpiani Pedro. "Modèle de plissement dynamique pour la simulation aux grandes échelles de la combustion turbulente prémelangée". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLC005/document.
Pełny tekst źródłaLarge eddy simulation (LES) is currently applied in a wide range of engineering applications. Classical LES combustion models are based on algebraic expressions and assume equilibrium between turbulence and flame wrinkling which is generally not verified in many circumstances as the flame is laminar at early stages and progressively wrinkled by turbulent motions. In practice, this conceptual drawback has a strong consequence: every computation needs its own set of constants, i.e. any small change in the operating conditions or in the geometry requires an adjustment of model parameters. The dynamic model recently developed adjust automatically the flame wrinkling factor from the knowledge of resolved scales. Widely used to describe the unresolved turbulent transport, the dynamic approach remains underexplored in combustion despite its interesting potential. This thesis presents a detailed study of a dynamic wrinkling factor model for large eddy simulation of turbulent premixed combustion. The goal of this thesis is to characterize, unveil pros and cons, apply and validate the dynamic modeling in different flow configurations
Pang, Hyo Sun. "Etude de l'application du modèle Cora au cas d'un brûleur industriel à contre rotation". Rouen, 1991. http://www.theses.fr/1991ROUES026.
Pełny tekst źródłaQuilichini, Virginie. "Etude de la structure des flammes laminaires partiellement prémélangées dans une chaudière domestique modèle". Châtenay-Malabry, Ecole centrale de Paris, 2000. http://www.theses.fr/2000ECAP0858.
Pełny tekst źródłaLarass, Nikos. "Caractérisation expérimentale des champs thermiques et dynamiques de la combustion dans une chaudière domestique modèle". Rouen, 2000. http://www.theses.fr/2000ROUES004.
Pełny tekst źródłaBoudier, Pascal. "Modélisation des phases d'initiation et de propagation d'une flamme turbulente prémélangée par le modèle de flamme cohérente : application au cas du moteur à allumage commandé". Châtenay-Malabry, Ecole centrale de Paris, 1992. http://www.theses.fr/1992ECAP0248.
Pełny tekst źródłaBellemare, Laurent. "Un modèle multiphasique de prédiction du comportement d'un feu de végétation". Aix-Marseille 1, 2000. http://www.theses.fr/2000AIX11008.
Pełny tekst źródłaEmery, Pascal. "Modélisation simplifiée des moteurs essence à injection directe par réduction des modèles physiques multidimensionnels". Paris 6, 2002. http://www.theses.fr/2002PA066122.
Pełny tekst źródłaMelen, Stéphane. "Modélisation et étude numérique de la combustion supersonique turbulente non-prémélangée, approche probabiliste". Rouen, 1995. http://www.theses.fr/1995ROUE5044.
Pełny tekst źródłaMaistret, Eric. "Représentation et simulation de la combustion turbulente par le modèle de flamme cohérente : application aux foyers aéronautiques". Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0199.
Pełny tekst źródłaDelamare, Ludovic. "Modélisation numérique de la propagation d'une flamme turbulente en milieu confiné". Rouen, 1992. http://www.theses.fr/1992ROUES057.
Pełny tekst źródłaCharmantray, Clothilde. "Transversalisation d'un modèle nodal de comportement thermique d'un diesel à basse température en régime transitoire". Ecully, Ecole centrale de Lyon, 2008. http://bibli.ec-lyon.fr/exl-doc/TH_T2173_ccharmantray.pdf.
Pełny tekst źródłaIn the context of drastic reduction of CO2 and pollutant emissions, numerical simulation is the key instrument to evaluate strategies to optimize thermal management of Diesel engines, especially during cold warm-up. Many numerical models exist, but a problem lies in their application to different engine configurations and for large operating conditions. Our work is based on an existing thermal model, and also on our own analysis of test results for 4 DI Diesel engines, of various sizes (from 1. 5 to 2. 2 liters Diesel engines). We identified 3 critical aspects in the modelling. The first is nodal cutting, the two others are relative to the description of the heat sources in the nodal model: heat flux through the combustion chamber walls and energy released by friction. The challenge is then to find the right compromise between the level of modelling, the data available to supply the thermal model (depending on the stage of engine development) and the precision expected. We have therefore proposed an organic nodal cut which correctly describes the local behaviour of the cylinder head. We have identified the good level of modelling to describe correctly friction, especially at very low temperatures and proposed a methodology to integrate these results in the thermal model. Finally, to improve the description of gaswalls exchanges during cold warm-up and take into account the influence of combustion parameters, we have chosen, calibrated and validated multi-zone combustion model, included in a thermodynamic cycle simulator. The coupling between thermal and combustion models can significantly improve the response of thermal model in cold conditions
Pommier, Pierre-Lin. "Modélisation de l'interaction cinétique chimique - turbulence : application à la combustion homogène diesel". Paris 6, 2008. http://www.theses.fr/2008PA066354.
Pełny tekst źródłaThe objective of this thesis is to study the interaction between chemical kinetics and turbulence applied to homogeneous Diesel combustion (HCCI). Heterogeneities air-fuel mixture control the heat release rate and are directly linked to emissions during the engine cycle. The proposed model based on a particular method takes into account the heterogeneities of temperature and species present in the combustion chamber. Heterogeneities are modelled by random vectors (i. E. Particles) of species mass and temperature. The 0D model used describes two physical phenomena: the chemical kinetics and the mixture between the particles. The micro-mixing time is modelled by a k-ε turbulence model. Model against experimental data shows overall satisfactory agreement. However, this approach is very promising and can be linked to 3D approach, where this model can be implemented in each computational cell
Nicoloso, Julien. "Combustion confinée d'explosif condensé pour l'accélaration de projectile. Application en pyrotechnie spatiale". Phd thesis, ISAE-ENSMA Ecole Nationale Supérieure de Mécanique et d'Aérotechique - Poitiers, 2014. http://tel.archives-ouvertes.fr/tel-01060036.
Pełny tekst źródłaLeghouchi, Essaïd. "Application du modèle feu dans l'évaluation du risque des incendies de forêt et mise au point d'une méthode d'étude de la toxicité des retardants". Rouen, 1995. http://www.theses.fr/1995ROUE03NR.
Pełny tekst źródłaA fire model, allowing to record simultaneously physico-chemical and toxicological data, has been used to evaluate the risk linked to materials and chemical compounds submitted to thermal degradation. During this work, the use of this fire model has been extended to the evaluation of toxicity of vegetal material decomposition gales. In the second step, the toxicity of chemical fire retardants has been studied either atone either alter application to vegetal material in fire situations. To evaluate the toxic hasard occuring during vegetals and fire retardants thermal decomposition, two bioassays have been used mite exposure to gales and growth inhibition of microalga Selenastrum capricornutum. This study allowed us to compare vegetals and to classify them according their potentiel toxic risks. Dry plants fumes were significantly more dangerous than fresh plants ones. The fire retardants tests showed the reliability of the fire model for loch a study. The fireproofing with these products shows clearly a more important effect on fire risk than on toxic risk
Amara, Salah. "Elaboration et validation d'un modèle de transferts thermiques instationnaires gaz-paroi dans la chambre de combustion d'un moteur". Ecully, Ecole centrale de Lyon, 1994. http://bibli.ec-lyon.fr/exl-doc/TH_T1547_samara.pdf.
Pełny tekst źródłaDuval, Benoît. "Optimisation de maillages non structurés dans des géométries déformables". Rouen, 1996. http://www.theses.fr/1996ROUES022.
Pełny tekst źródłaBernigaud, Pierre. "Modélisation de la combustion des matériaux énergétiques nouvelle génération". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAE017.
Pełny tekst źródłaUsed in civil and military rocket engines, composite propellants are characterized by a heterogeneous structure at the microscopic level. They consist mainly of oxidizer particles embedded in a polymer matrix known as the binder. The binder maintains the structural integrity of the propellant, and produces via its pyrolysis gases whose combustion is responsible for most of the heat release within the flame. The combustion products of the oxdizer particles oxidize the fuel generated by the binder.Ammonium perchlorate (AP) is a widely used oxidizing agent in composite propellants, mainly in association with a polymer binder such as hydroxytelechelic polybutadiene (HTPB). Next-generation propellants could include nitramines in their composition, such as hexogen (RDX), as a partial replacement for AP for certain specific purposes. In particular, reducing the amount of AP contained in the propellant can limit the formation of a visible trail at the engine exhaust, reducing the vehicle's signature.In this thesis, we propose to revisit the studies carried out on the combustion of conventional AP/HTPB propellants, and to characterize the effect of RDX inclusion in their composition.To this end, the first part of the thesis is dedicated to the development of combustion models for the ingredients under consideration: AP, homogenized AP/HTPB blend, and RDX.A chemical kinetics mechanism is assembled, capable of representing the chemical processes characteristic of the combustion of all these energetic materials. For each ingredient, a condensed-phase decomposition model is also formulated, to be associated with the kinetic mechanism. One-dimensional simulations are then carried out using a coupled flame/solid approach, in order to validate the whole on available experimental data.Due to their heterogeneous structure, the study of composite propellant combustion requires the use of multidimensional numerical methods. A second part of the thesis is therefore dedicated to the development and validation of a 2D calculation code, enabling the simulation of the combustion of an oxidizer particle surrounded by a layer of binder, in an axisymmetric configuration.In a final section, the combustion models and the computational code are used in conjunction to study the effect of RDX inclusion in a conventional AP/HTPB propellant. For the first time, the flame structure produced by such AP/HTPB/RDX propellant is obtained and characterized. The effect of pressure and RDX particle size on propellant regression is investigated, demonstrating the existence of different combustion regimes. Recommendations are made for optimizing the performance of this type of composition
Gonzalez, Michel. "Contributions à la simulation numérique d'écoulements avec combustion". Rouen, 1986. http://www.theses.fr/1986ROUES011.
Pełny tekst źródłaBéard, Philippe. "Modélisation lagrangienne de la dispersion et de l'évaporation de gouttes dans un écoulement turbulent instationnaire". Toulouse, ENSAE, 1994. http://www.theses.fr/1994ESAE0004.
Pełny tekst źródłaPark, Jie-Won. "Réduction des oxydes d'azote émis lors de la combustion du gaz naturel, par des composés organiques oxygènes". Paris 6, 2005. http://www.theses.fr/2005PA066103.
Pełny tekst źródłaHoernel, Jean-David. "Etudes théorique et numérique d'un modèle non-stationnaire de catalyseurs à passages cylindriques". Phd thesis, Université de Haute Alsace - Mulhouse, 2002. http://tel.archives-ouvertes.fr/tel-00002403.
Pełny tekst źródłaNous établissons l'existence et l'unicité de la solution, ainsi que quelques propriétés qualitatives de cette solution, en particulier l'existence de bornes supérieures et inférieures. Nous étudions également le comportement limite de la solution quand le temps tend vers l'infini.
Nous mettons ensuite en oeuvre une méthode numérique permettant d'obtenir des courbes décrivant le comportement de la solution.
Caudal, Jean. "Simulation numérique du reformage autothermique du méthane". Phd thesis, Ecole Centrale Paris, 2013. http://tel.archives-ouvertes.fr/tel-00862538.
Pełny tekst źródłaYounes, Rafic. "Elaboration d'un modèle de connaissance du moteur diesel avec turbocompresseur à géométrie variable en vue de l'optimisation de ses émissions". Ecully, Ecole centrale de Lyon, 1993. http://bibli.ec-lyon.fr/exl-doc/TH_T1530_ryounes.PDF.
Pełny tekst źródłaI. C. Reciprocating engines are strongly restricted by the increasing pollutants rules end fuel consumption. Among others Diesel technologies, the use of variable nozzle turbocharger (V. N. T. ) is a realistie technical way. In this study, the consequences of this component on emissions and consumption are examined in order to realize future control process based on a mixed criteria of these two aspects. After an inventory of differents models, we built, in first step, a model of turbocharged Diesel engine in transient conditions. This model is non linear, simple, but sufficiently precise for the propose of optimal control of engine. It is based on correlative or knowledge sub models describing internal variables such as engine speed, turbocharged pressure and emissions such as unburned hydrocarbons and smoke Index. Experiments developed on a 250 kW Diesel turbocharged engine, with variable nozzle positions in stationnary and transient conditions 1) show the influence of this technology on various pollutants, and 2) are compared with the computed one. In the second step, Diesel engine control is introduced. This control is based on inlet pressure as a feed back variable with rack position, engine speed and nozzle position as input variables. Some references have been deduced from experiments and, finalley, a linearized control model of the inlet pressure is proposed
Vanhille, Didier. "Formation de CO et de NOx dans un moteur à allumage commandé". Rouen, 1991. http://www.theses.fr/1991ROUE5023.
Pełny tekst źródłaObounou, Marcel. "Modélisation de la combustion turbulente non prémélangée avec prise en compte d'une cinétique chimique complexe". Rouen, 1994. http://www.theses.fr/1994ROUE5011.
Pełny tekst źródłaTakali, Sabri. "Etude d'un électrobrûleur industriel doté d'une torche à arc triphasée pour la valorisation énergétique de combustibles à faible pouvoir calorifique". Thesis, Paris, ENMP, 2015. http://www.theses.fr/2015ENMP0071/document.
Pełny tekst źródłaEnergy production from renewable combustibles like biomass and organic wastes presents an increasing interest with the urgent need to reduce greenhouse gas emissions and the depletion of conventional fossil energy resources. Meanwhile, standard industrial burners are not adequate for the energetic valorization of renewable poor LHV combustibles despite their low price and their abundance in nature. Electro-burners, with plasma assisted combustion technology, are a promising solution for this type of combustible. In this PhD dissertation is detailed the development of a 100 kW plasma torch working in air and embeddable in an industrial electro-burner. It consists firstly, in making possible an operation in oxidizing environment by reducing as much as possible the air erosion of the graphite electrodes. For this purpose, multiple solutions are tested such as sheathing with nitrogen and methane, aerodynamic control of air flow and injection of carbon black particles. The second challenge is the optimization of heat and mass transfers by improving the plasma flow and by choosing the appropriate materials for thermal insulation. Theoretically, a turbulent model of plasma flow is developed with the modeling of the electric arc column as a stationary source of heat and momentum. A multi-band radiation model and a reactional kinetic model are also integrated. The results show the important role of radiation, the limitation of the nitrogen sheathing and the potential of methane injection in reducing electrode erosion. They allowed also validating the design of the plasma torch before the tests. Experimentally, the new torch design is built and tested. It comes out that reducing the electrode erosion by carbon powder injection is not efficient to achieve a neutral environment around the electrodes whereas a control of the nearby air flow appears to be beneficial. Finally, tests of plasma assisted combustion of some biomasses are performed and analyzed
Emmanuelli, Ariane. "Numerical simulation and modelling of entropy noise in nozzle and turbine stator flows". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC067.
Pełny tekst źródłaThe investigation of combustion noise is motivated by its growing relative contribution to the noise emitted by modern turbofan engines overall, as well as its effect on low NOx emission combustor design. Entropy noise is a source of indirect combustion noise, which is generated by the acceleration of heterogeneities, in this case entropy, downstream of the combustion chamber. This study consists of the investigation of entropy noise in nozzle and turbine stator flow using both analytical and numerical methods. Nozzle flow is considered first. A Computational AeroAcoustics (CAA) reference case is built for the validation of an existing two-dimensional semi-analytical model developed under similar assumptions. The levels of entropy noise and acoustic scattering estimated using both methods are in good agreement. Two-dimensional effects on entropy noise are highlighted, notably by comparison with compact and 1D models. In addition, vorticity induced by the acceleration of entropy noise is evidenced, but it yields negligible vortex sound. Next, the focus is shifted to a 2D high-pressure turbine stator. The 2D model for nozzle flow is extended to this configuration, inheriting some of its main assumptions. Their investigation, using CAA in particular, sets the path for future developments and allows insight to be gained into the role of both vorticity and azimuthal variation of acoustics, which are neglected by the model. CAA also allows to characterise entropy noise generation in 2D stator flow under simplifying assumptions, using Euler and RANS mean flows. Further investigation is needed to validate the RANS case and to fully understand the effect of boundary layers on entropy noise generation. Finally, entropy noise is simulated using Zonal Detached Eddy Simulation (ZDES) in a stator channel in order to investigate 3D and viscous effects on entropy noise. The three-dimensionality of the flow is highlighted and acoustic signals are carefully post-processed, ensuring hydrodynamic perturbations are correctly filtered and boundary reflections are minimised. The closeness of noise levels obtained using CAA and ZDES suggest three-dimensional and viscous effects have a limited impact on the entropy noise generated in turbine stator flow
Picard, Mathieu. "Dynamique des gaz et combustion du Rim-Rotor Rotary Ramjet Engine (R4E)". Mémoire, Université de Sherbrooke, 2011. http://savoirs.usherbrooke.ca/handle/11143/1607.
Pełny tekst źródłaChauvy, Marc. "Simulation de la formation de la Post-oxydation des hydrocarbures imbrûlés pour les moteurs essence". Rouen, 2009. http://www.theses.fr/2009ROUES006.
Pełny tekst źródłaDue to the Euro5 norms, for gasoline combustion, new strategies of injection and combustion (for instance: direct injection, exhaust gas recirculation, combustion by auto-ignition) are studied to reduce: consumption, nitrogen oxides emissions and precious metals for catalyzer. Unfortunately, these new strategies tend to increase the unburnt hydrocarbon (HC) emission levels. Various studies show that a main mechanism of HC production is the flame / wall interaction (FWI). The first goal of this study consists in selecting two chemicals mechanisms for gasoline (a semi-detailed and a skeletal) to represent HC formation: Golovichev (121 species and 611 reactions) and Hasse (29 species and 48 reactions). To model FWI, first, we use a Stochastic Reactor Model (MRS) with Golovichev using a wall exchange model based on Curl Modified. The study of different physical parameters (pressure, wall temperature Tp, equivalence ratio and intensity of wall contact) allows to understand how flame wall interaction and unburnt HC progress during combustion. Thus when the combustion occurs "ideally", HC production is very low. However, when combustion is incomplete, HC levels becomes very high. Finally, a progress variable CHC is defined to obtain a simple representation of HC evolution during the combustion. In a second part, two configurations are considered with Hasse: head-on quenching (HOQ) on a planar wall and in crevices. The aim of this part is to use laminar flame simulation (LFS) to understand how the unburnt HC are produced near the wall. In the HOQ configuration, the flame front propagates toward the cold wall where quenching occurs. Several aspects of flame wall quenching such as oxidation of unburnt HC, wall heat flux, quench distances as well as HC families are investigated by varying parameters like Tp and . In a second part, crevices are considered to study the impact of wall imperfections in combustion chambers. Configurations with different Tp and thickness (e) are tested. When the crevice is not wide enough and Tp too cold, the flame cannot propagate in the device and the quantity of HC is smaller than in the case where the flame can propagate (but the fuel is not oxidized). If the crevice is wide enough to allow a propagating flame, HOQ occurs at the bottom of the crevice and HC with fuel accumulate in the corners. The computational results obtained in this work demonstrate the ability of LFS to reproduce incomplete combustion mechanisms that are responsible for a major part of HC production in gasoline engines. Finally, a feasibility study of integration of HC tabulation in turbulent combustion model ECFM for RANS simulation has been realized
Da, silva Rodrigues Sofia. "Riser hydrodynamic study with Group B particles for Chemical Looping Combustion". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10230/document.
Pełny tekst źródłaChemical Looping Combustion (CLC) is an oxy-combustion like process where particles are used to supply oxygen to combustion. Further work is still needed for extrapolation and optimization of the CLC process, concerning properties of Group B particles and CFB technology. Hydrodynamic tests were made on a 18 m tall riser. Axial pressure profiles as well as radial flux profiles and radial momentum quantity profiles were obtained. Three types of Group B particles were used with Sauter mean diameters between 250 and 300 μm and densities between 2600 and 3300 kg/m²s. An important impact of particle sphericity on riser pressure drop has been revealed. At identical conditions, glass beads present about half the pressure drop generated by sand. In the developed region of the riser, the core-annulus regime has been found. A 1D model of the riser, based on experimental results and on the Euler-Euler gas-solid equations, has been developed. Moreover, a new cross section averaged drag force correlation is presented. A new boundary condition on the bottom of the riser has been investigated. The final 1D model is capable of predicted riser pressure drop from the operating conditions and it takes into account particle properties such as density, size and shape. A study on the adequacy of the use of the commercial CFD code Barracuda to simulate risers with Group B particles was made. It was shown that the code under estimates pressure drop along the riser for sand simulations
Truchot, Benjamin. "Développement et validation d'un modèle eulérien en vue de la simulation des jets de carburants dans les moteurs à combustion interne". Phd thesis, Toulouse, INPT, 2005. http://oatao.univ-toulouse.fr/7465/1/truchot.pdf.
Pełny tekst źródłaPecquery, François. "Développement d'un modèle numérique de prédiction des émissions d'oxydes d'azote pour la simulation aux grandes échelles de chambres de combustion aéronautiques". Phd thesis, INSA de Rouen, 2013. http://tel.archives-ouvertes.fr/tel-00949132.
Pełny tekst źródłaMaurel, Stéphane. "Étude par imagerie laser de la génération et de la rupture d'un écoulement tourbillonnaire compressé : situation modèle pour la validation de simulations aux grandes échelles dans les moteurs". Toulouse, INPT, 2001. http://www.theses.fr/2001INPT035H.
Pełny tekst źródłaBennadji, Hayat. "Biodiesel : combustion des esthers éthyliques d'huiles végétales comme additifs au pétrodiesel". Thesis, Vandoeuvre-les-Nancy, INPL, 2010. http://www.theses.fr/2010INPL044N/document.
Pełny tekst źródłaAn increasingly popular biofuel is biodiesel, composed of a mixture of saturated and unsaturated fatty acid methyl or ethyl esters, with a long aliphatic main chain. This PhD dissertation provides a literature review concerning the origin of biodiesel, its manufacturing process, performance and emissions of diesel engines fueled with biodiesel, and the kinetics of oxidation of biodiesel. Efforts were made to highlight the main differences between methyl and ethyl esters while showing where further research needs to be developed or pursued. For these reasons, the autoignition of five esters were measured behind reflected shock tube: ethyl acrylate, methyl acrylate, ethyl crotonate, methyl crotonate, and ethyl butanoate. Detailed mechanisms for the oxidation of the five studied esters were automatically generated using the version of EXGAS software. In addition, the oxidation of ethyl butanoate as a model compound for Fatty Acid Ethyl Esters (FAEE) has been investigated in tubular plug flow reactor at atmospheric pressure over wide range of temperature (500-1200 K). The results consist of concentration profiles of the reactants, stable intermediates, and final products. The model was again validated satisfactorily by comparison between computed results and the generated experimental data
Dumont, Nicolas. "Méthodes numériques et modèle réduit de chimie tabulée pour la propagation d'incertitudes de cinétique chimique". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC037.
Pełny tekst źródłaNumerical simulation plays a key role in the field of combustion today, either in the research area by permitting a better understanding of phenomenons taking place inside reactive flows or in the development of industrial application by reducing designing cost of systems. Large Eddy Simulation is at the time the most suited tool for the simulation of reactive flows. Large Eddy Simulation of reactive flows is in practice only possible thanks to a modeling of different phenomenons:- turbulence is modeled for small structures allowing to resolve only big structures which results in lower computational cost- chemistry is modeled using reduction methods which allows to drastically reduce computational costThe maturity of Large Eddy Simulation of reactive flows makes it today a reliable, predictive and promising tool. It now makes sense to focus on the impact of the parameters involved in the different models on the simulation results. This study of the impact of the modeling parameters can be seen from the perspective of uncertainties propagation, and can give interesting informations both from a practical side for the robust design of systems but also on the theoretical side in order to improve the models used and guide the experimental measurements to be made for the reliability improvement of these models.The context of this thesis is the development of efficient methods allowing the propagation of uncertainties present in the chemical kinetic parameters of the reaction mechanisms within Large Eddy Simulation, these methods having to be non-intrusive in order to take advantage of the existence of the different computation codes which are tools requiring heavy means for their development. Such a propagation of uncertainties using a brute-force method suffers from the "curse of dimensionality" because of the large number of chemical kinetic parameters, implying a practical impossibility with the current means of computation which justifies the development of efficient methods.The objective of the thesis is the development of a reduced model that can be used for uncertainties propagation in Large Eddy simulations. The handling and implementation of various tools resulting from the uncertainties propagation framework has been an essential preliminary work in this thesis in order to bring this knowledge and skills into the EM2C laboratory.The method developed in this thesis for the propagation of chemical kinetic parameters uncertainties is limited to chemistry models in which the advancement of the combustion process is summarized by the evolution of a progress variable given by a transport equation, the access to other informations being made through the use of a table. Through the study of the evolution of a constant pressure adiabatic reactor containing a homogeneous mixture of air and dihydrogen, it is shown that a large part of the uncertainties of such a system can be explained by the uncertainties of the progress variable. This makes it possible to define a chemical table that can be used to propagate uncertainties of chemical kinetic parameters in Large Eddy Simulations. The introduction of the uncertainties is then done only by the modeling of the source term present in the transport equation of the progress variable, which can be parameterized with the help of few uncertain parameters thus avoiding the "curse of dimensionality"
Varin, Étienne. "Etude et développement du modèle de combustion turbulente PEUL : Application à la prédiction de la formation des suies dans les foyers aéronautiques". Rouen, 1998. http://www.theses.fr/1998ROUES033.
Pełny tekst źródłaThis work deals with the numerical simulation of turbulent reactive flows. The aim of the study is to develop a model able to predict soot formation in aeronautical chambers. We use a Probalistic Eulerian Lagrangian (PEUL) method to describe the turbulent combustion. With this model, the velocity field is calculated by solving Navier-Stokes equations. Chemical composition and temperature fields are obtained by solving the Probability Density Function transport equation with a Monte Carlo method. A soot model is coupled to the combustion model in order to compute soot levels. The different processes of soot formation and destruction are taken into account: precursors formation, nucleation, surface growth, coagulation and oxidation of soot particles. We compare computation results with experimental results in the case of an ethylene/air turbulent diffusion flame. Finally, an application of our model to a practical case is related. The three dimensional numerical simulation of an aeronautical combustion chamber is presented
Pousse, Émir. "Étude cinétique de la combustion en flamme prémélangée de molécules modèles présentes dans les gazoles". Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL002N/document.
Pełny tekst źródłaThe HCCI engine could be an interesting alternative to conventional combustion processes. However, the control of the combustion remains difficult in this engine because, unlike the gasoline and diesel engine, it is directly related to the chemical oxidation of fuel. The development of accurate detailed kinetic models of the oxidation of fuel is therefore essential to control this mode of combustion. The aim of this PhD was to develop and experimentally validate high temperature kinetic oxidation models for 3 molecules representative of diesel fuel by using a flat flame burner experimental device. This study presents new experimental results obtained in a lean laminar premixed methane flame seeded respectively with n butylbenzene, n propylcyclohexane and indane. A kinetic oxidation model was developed and validated at high temperature for n-butylbenzene and another one was validated in flame for n propylcyclohexane. Overall, the models correctly simulated the profiles of most products measured in the flames. Moreover, a qualitative kinetic model for the oxidation of indane has been proposed
Delaroque, Aurélie. "Élaboration d’un outil numérique pour la réduction et l’optimisation des mécanismes cinétiques pour les systèmes de combustion". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS417.
Pełny tekst źródłaIn the modeling of a combustion process, obtention of global data such as flame speed can, under certain circumstances, be achieved through extremely reduced mechanisms. On the contrary, prediction of detailed data such as polluant species requires the use of detailed kinetic mechanisms involving many chemical species. Due to the size and to the presence of many differents time scales, the integration of those models to complex numerical simulations is a non trivial task. A reduction tool based on Directed Relation Graph and sensitivity analysis methods is proposed to tackle this issue. Reduced mechanisms fitting user defined tolerances for quantities of interest such as global (flame speed, ignition delay, etc) and detailed data (concentration profiles) are automatically generated. The reduction process is paired up with an optimisation of reaction rates through a genetic algorithm to make up for the error induced by the loss of information. This process can use both numerical and experimental reference entries. The complete numerical tool has been tested on several canonical configurations for several fuels (methane, ethane and n-heptane) and reduction rates up to 90% have been observed
Vanhove, Guillaume. "Oxydation, co-oxydation et auto-inflammation à basses températures d'alcènes et aromatiques types : étude expérimentale des interactions au sein d'un carburant-modèle". Lille 1, 2004. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2004/50376-2004-213-214.pdf.
Pełny tekst źródłaUne étude comparative détaillée de la réactivité de trois isomères de position: les 1-, 2-, et 3-hexènes a été réalisée entre 600 et 900 K, 5 et 25 bar. Des chemins réactionnels spécifiques de la double liaison sont mis en jeu, et les trois h'exènes présentent chacun un poids différents des réactivités'de la chaîne alkyle et de la double liaison. Dans les mêmes conditions de température et de pression, les aromatiques et les alcènes sont moins réactifs que les alcanes, mais on a montré qu'ils sont susceptibles d'être oxydés plus rapidement lorsqu'ils se trouvent mélangés à un alcane. Trois mélanges binaires ont été étudiés: Un mélange toluène/iso-octane, un mélange 1-hexène/iso-octane, et un mélange 1-hexène/toluène. A partir de la mesure des délais d'autoinflammation et des produits d'oxydation intermédiaires des deux composés impliqués dans les mélanges, il est apparu que deux types d'interactions existent entre les mécanismes d'oxydation, soit par le pool de petits radicaux créé par le composé le plus réactif, soit par la recombinaison de radicaux hydrocarbonés originaires des deux partenaires. Les données collectées dans le cas des hydrocarbures purs ou en mélange binaire ont été utilisées afin d'interpréter les résultats obtenus avec un carburant-modèle représentatif de la composition des carburants commerciaux pour moteur à allumage commandé et composé d'iso-octane, de 1-hexène et de toluène
Rochette, Bastien. "Modeling and simulation of two-phase flow turbulent combustion in aeronautical engines". Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0059.
Pełny tekst źródłaNowadays, more than 80% of the energy consumed on Earth is produced by burning fossil fuels. Alternative solutions to combustion are being developed but the specific constraints related to air transport do not make it possible to currently power engines without introducing a technological breakthrough. These findings explain the research activity to improve the knowledge and the control of combustion processes to design cleaner, and more efficient aeronautical engines. In this framework, Large Eddy Simulations (LES) have become a powerful tool to better understand combustion processes and pollutant emissions. This PhD thesis is part of this context and focuses on the models and numerical strategies to simulate with more accuracy turbulent gaseous and two-phase reacting flows in the combustion chamber of aeronautical engines. First, a generic and self-adapting method for flame front detection and thickening has been developed for the TFLES model, and validated on several academic configurations of increasing complexity. This generic approach is then evaluated in the LES of a laboratory-scale burner and compared to the classical thickening method. Results show a more accurate thickening in post-flame regions. Second, from the analysis of 1-D homogeneous laminar spray flames where the dispersed phase has a relative velocity compared to the carrier phase, two analytical formulations for the spray flame propagation speed have been proposed and validated. The agreement between the overall trend of both the measured/estimated spray flame speeds demonstrates that the model and its parameters correctly take into account the main physical mechanisms controlling laminar spray flames. Finally, the state-of-the-art TFLES models were tested on complex turbulent gaseous and two-phase reacting configurations. The pros and cons of these models were investigated to contribute to the understanding of the mechanisms related to turbulent combustion, and to propose a LES modeling strategy to improve the fidelity of reactive simulations
Nuglisch, Hans-Joachim. "Étude expérimentale d'un jet axisymétrique compressé : situation modèle de l'aérodynamique interne des moteurs à pistons". Toulouse, INPT, 1992. http://www.theses.fr/1992INPT101H.
Pełny tekst źródłaKacem, Ahmed. "Modélisation numérique de la pyrolyse en atmosphères normalement oxygénée et sous-oxygénée". Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4708/document.
Pełny tekst źródłaThe pyrolysis rate is a key parameter controlling fire behavior, which in turn drives the heat feedback from the flame to the fuel surface. In the present study an in–depth pyrolysis model of a semi–transparent solid fuel with spectrally–resolved radiation and a moving gas/solid interface was coupled with the CFD code ISIS. A combined genetic algorithm/pyrolysis model was used with Cone Calorimeter data from a pure pyrolysis experiment to estimate a unique set of kinetic parameters for PMMA pyrolysis. In order to validate the coupled model, ambient air flaming experiments were conducted on square slabs of PMMA. From measurements at the center of the slab, it was found that the experimental regression rate becomes almost constant with time, and that the radiative contribution to the total heat flux remains almost constant. Coupled model results show a fairly good agreement with the literature and with current measurements. Nevertheless, the flame heat flux feedback at the edges of the slab is underestimated. Predicted flame heights based on a threshold temperature criterion were found to be close to those deduced from the correlation of Heskestad. Finally, in order to predict the pyrolysis of PMMA under reduced ambient oxygen concentration, a two–step chemical reaction and a flammability diagram for flame extinction was used. Model results are compared with data obtained in the experimental facility CADUCEE for ambient oxygen concentrations of 18.2 and 19.5%. Data show that the total mass loss rate and flame temperature decrease with the oxygen concentration, which is well reproduced by the model