Дисертації з теми "Moteurs fusée"
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Lefrançois, Emmanuel. "Modèle numérique de couplage fluide-structure avec application aux moteurs fusée." Rouen, 1998. http://www.theses.fr/1998ROUES061.
Iannetti, Alessandra. "Méthodes de diagnostic pour les moteurs de fusée à ergols liquides." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS243.
The main objective of this work is to demonstrate and analyze the potential benefits of advanced real time algorithms for rocket engines monitoring and diagnosis. In the last two decades in Europe many research efforts have been devoted to the development of specific diagnostic technics such as neural networks, vibration analysis or parameter identification but few results are available concerning algorithms comparison and diagnosis performances analysis.Another major objective of this work has been the improvement of the monitoring system of the Mascotte test bench (ONERA/CNES). This is a cryogenic test facility based in ONERA Palaiseau used to perform analysis of cryogenic combustion and nozzle expansion behavior representative of real rocket engine operations.The first step of the work was the selection of a critical system of the bench, the water cooling circuit, and then the analysis of the possible model based technics for diagnostic such as parameter identification and Kalman filters.Three new algorithms were developed, after a preliminary validation based on real test data, they were thoroughly analyzed via a functional benchmark with representative failure cases.The last part of the work consisted in the integration of the diagnosis algorithms on the bench computer environment in order to prepare a set-up for a future real time application.A simple closed loop architecture based on the new diagnostic tools has been studied in order to assess the potential of the new methods for future application in the context of intelligent bench control strategies
Schreiber, Didier. "Quelques problèmes de combustion lies à l'allumage dans les moteurs fusée cryotechniques." Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0204.
Lacas, François. "Modélisation et simulation numérique de la combustion turbulente dans les moteurs fusée cryotechniques." Châtenay-Malabry, Ecole centrale de Paris, 1989. http://www.theses.fr/1989ECAP0095.
Bernardi, Jean de. "Aspects expérimentaux et théoriques des instabilités de cavitation dans les turbopompes de moteurs de fusée." Grenoble INPG, 1996. http://www.theses.fr/1996INPG0217.
Hydraulic loop instabilities and radial forces generated by partial cavitation on a turbopump inducer were investigated in water with the 4-bladed inducers of the ARIANE 5 VULCAIN engine liquid hydrogen and oxygen turbopumps. With the help of the synchronization of high speed movies with radial load measurements on the inducer shaft and with the dynamic pressures signals, we could establish an identification method and an analysis approach to the instabilities in a turbopump cavitating inducer. Characteristic frequencies of unsteady cavitation phenomenon were identified at various operating points. This analysis clearly demonstrates the evolution of radial loads with cavitation number : (1) constant, (2) rotating and supersynchronous, (3) chaotic, (4) constant. The evolution of radial load is strongly related to cavitation configurations. Instabilities of cavitating 4-bladed inducer have been explained qualitatively and imbalances have been estimated in terms of radial loads and cavity lengths. This study has been completed by a theoretical model of the inducer based on the actuator disk theory in which the cavitating volume appears to be the main parameter. A measuring method of the cavitating volume in the rotary inducer is therefore proposed which could give results with a 90% accuracy
Gioud, Thibault. "Simulation aux grandes échelles de l'atomisation pour moteur-fusée à injection liquide en regime sous-critique." Electronic Thesis or Diss., Université de Toulouse (2023-....), 2024. http://www.theses.fr/2024TLSEP049.
In recent years, the space launchers market has experienced significant growth, marked by the emergence of increasingly compact satellites and a progressively more affordable production cost, attributable to recent technological advancements. This cost reduction has met the rising demand, with new private entities entering the launcher manufacturing sector. A key strategy to minimize costs lies in the use of methane as a fuel, replacing hydrogen, which incurs significantly higher operating costs (storage, temperature, etc.) despite superior performance.The evolution of numerical models and the increasing computational power have made numerical simulation particularly attractive for predicting and optimizing the performance and lifespan of rocket engines. This PhD thesis focuses on Large Eddy Simulation of rocket engine combustion in sub-critical regimes. Rocket engines can experience multiple thermodynamic conditions, ranging from sub-critical to supercritical regimes. In sub-critical regimes, one or both propellants may exist in a liquid state. The presence of a two-phase mixture (gas + liquid) makes numerical simulation complex due to the strong gradients at the liquid/gas interface. Therefore, developing models able to represent this interface and its dynamics under various thermodynamic conditions is an undergoing research direction.In this thesis, the diffuse multi-fluid interface method, assuming equilibrium of temperature, pressure, velocity, and Gibbs potentials, is used to simulate two-phase flows in rocket engine conditions. This approach aims to address the challenges associated with the complexity of numerical simulations arising from the presence of a two-phase mixture. Additionally, the approach considers surface tension forces, which play a crucial role in atomization phenomena. This method has been evaluated on a reactive configuration similar to a rocket engine (experimental setup investigated at the Technische Universität München (TUM)), yielding highly encouraging results and demonstrating the benefits of simulating the liquid jet compared to a method modeling it with Lagrangian particle injection.Injecting liquid into a gaseous atmosphere leads to atomization phenomena, manifested by a consecutive series of breakups in the streamwise direction. Far from the injection, droplets diameter becomes very small, making the precise resolution of these structures computationally expensive. Additionally, the use of a diffuse interface method does not provide the required accuracy for the complete capture of these atomization phenomena.Therefore, an approach is proposed, involving the simulation of larger structures using an Eulerian approach and modeling the smallest particles with a Lagrangian approach. A secondary atomization model then predicts the characteristics of the final spray. During this thesis, the coupling algorithm providing mass, energy, and momentum transfer between these two formalisms was implemented in a multi-species context. The entire strategy was evaluated on a Jet In Cross Flow (JICF) configuration, showing highly encouraging results, particularly for droplet size distribution.Finally, this coupling strategy was applied to simulate the reactive TUM case. Although the dedicated time did not allow for sufficient convergence time to draw conclusions, initial promising results demonstrate the capability and robustness of this methodology under reactive conditions. Moreover, this methodology provides access to statistical spray data, such as droplet size distributions and velocities
Leboucher, Nicolas. "Stabilité et atomisation d'une nappe annulaire liquide soumise à deux courants gazeux avec effets de swirl : application aux futurs moteurs fusée cryotechniques." Phd thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aéronautique, 2009. http://tel.archives-ouvertes.fr/tel-00476808.
Muller, Mathieu. "Modélisation de la combustion de gouttes d'aluminium dans les conditions d'un moteur fusée à propergol solide." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS267.
The purpose of this thesis is to study the aluminum (Al) droplet combustion in solid rocket motor propellant. We need to model this process to evaluate the burning time and the residues length because their characterization in real conditions is very complex. A combustion model of a single droplet with a multiphysical spherical approach has been developed taking into account various phenomena. This model has been validated and used to study gaseous and surface mechanisms. Simulations in controlled atmospheres were made and the results were compared to experimental data. The study of the combustion of two particle classes (primary particle and agglomerate) under conditions typical for the Ariane 5 solid booster was conducted to evaluate the effect of different heterogeneous surface kinetics on the simulated combustion process. After the integration of the reactive surface model in the ONERA code CEDRE, simulations of the combustion using a two-dimensional axisymmetric approach were made to study the impact of the cap on the droplet surface and the convection velocity of oxidizers. By simulating the established combustion of two droplet classes at two pressures (5 and 9 MPa) in different stages of combustion, we evaluated main characteristics of the combustion and we deducted a global burning law. Finally, the heating of the droplet before an established combustion was studied to complete the characterization
Verthier, Brian. "Une étude sur les transferts associés aux écoulements diphasiques de fluides cryogéniques en microgravité : application à la mise en froid de moteurs-fusée." Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0104.
The objective of this thesis is to study the boiling regimes encountered during the transient cooling of a heated tube by an internal fluid flow. The experimental apparatus LORETA was designed for experiments on ground in vertical upward flow and on microgravity during parabolic flights. The effect of flow rate, liquid temperature and level of gravity in different boiling regimes has been clearly shown. A decrease of heat transfer in microgravity is observed, especially during film boiling. Models based on solving equations of two-fluid model allow the prediction for the two levels of gravity. The entire boiling curve could be modeled by modified laws of literature. The use of these laws for cryogenic fluids seems reasonable, given the comparison with some data from the bibliography
Kiyoshi, Shimote Wilson. "Modélisation des phénomènes d'ablation de l'insert d'une tuyère de moteur-fusée à propergol solide. Approche expérimentale et numérique." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2016. http://www.theses.fr/2016ESMA0028/document.
The main objective of this study is understand the ablation mechanisms in the presence of a critical environment in pressure and temperature within a solid propellant rocket motor. The well-known parameters, aluminum percentage in the flow, adiabatic flame temperature and the consequent heat flux in front of the geometry of the insert and its thermochemical properties are studied from anumerical and experimental strategy. The ablation phenomenon, which occurs at the nozzle insert during the operation of the solid propellant rocket motor, is th us studied and results of tests of the small and full-scale motors are presented as well as numerically simulated. Indeed, tests carried-out provide results on the conditions of the material of the insert before and after firing tests, do not allow is to provide a complete analysis of the development of the mechanisms involved during the running time of the engines. To introduce these rather complex physical phenomena a strategy of progressive development is followed. Initially, a 1D model treated the heat transfer equations using a multi-block numerical discretization technique. From the 1D method, simple expressions to represent the evolution of the ablation and pyrolysis fronts are defined. These expressions are then used directly on the treatment of axisymmetric problems and confronted with simulations of the scale motor. Finally, the immersed boundary method is applied to tackle coupling between flow and heat transfer on the insert, highlighting the phenomenon of ablation. The numerical simulations reproduce the experimental results and show a robust numerical methodology, corresponding to expectations in what concerns the evaluation of the ablation phenomenon within a solid propellant rocket motor nozzle
Baudoux, Pierre-Emmanuel. "Développement d'un modèle de transfert radiatif 3D adapté au calcul de la signature d'un jet de moteur-fusée dans l'ultraviolet." Phd thesis, Université de Rouen, 2002. http://tel.archives-ouvertes.fr/tel-00003328.
Gauffre, Marie-Charlotte. "Simulation numérique des écoulements diphasiques 3D instationnaires au cours du remplissage d'une maquette expérimentale eau / air du dôme LOX d'un moteur-fusée." Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0050.
New generation cryogenic upper-stage rocket engines are planned to be restartable during the orbit mission. The re-ignition of the engine is particularly difficult in space flight conditions. The engine contains a LOX dome fed with liquid oxygen (LOX) supplied by a bushel valve through a pipe. The gas / liquid mixture forming in the dome is injected into the combustion chamber through a number of injectors. Therefore the two-phase flow distribution at injectors outlet carries a real importance in terms of the ignition from the opening to the closing phases of the main valve. These flight conditions are of paramount importance, however, they are truly difficult to reproduce by experimental ground tests. In the framework of these studies, a research program set up by CNES (the French Space Agency) and SAFRAN Snecma, tries to study the LOX dome filling, through experiments and numerical studies. The aim is to identify the phenomena at sake to know the limit conditions at injectors, which will determine the ignition stage in the combustion chamber. Experiments are carried out at LEGI (Geophysical and Industrial Flows Laboratory in Grenoble) with substitution fluids (air and water), without heat and mass transfer on a rocket engine mockup. The work presented here, conducted at IMFT (Fluid Mechanics Institute in Toulouse), intends to reproduce the experimental results using incompressible two-phase flow simulations. The geometry used is representative of the experimental mockup composed of a feeding pipe, a dome, an igniter pipe and injectors. The aim of this study is to demonstrate the feasibility of a 3D unsteady two-phase flow calculation with the industrial code NEPTUNE_CFD, to simulate the LOX dome filling of the rocket engine, by taking into account the real geometry and the preponderant physical phenomena. The comparison of the predictions with the experimental results is carried out in order to estimate the code capability to predict the flow behavior, according to available closure laws. Finally, several sensitivity studies on the closure laws have been conducted to assess their influence on the numerical results. An important work has been carried out to obtain the proper inlet conditions to be imposed in the code in coherence with the experiments. Studies have equally been conducted on an isolated injector
Gonzalez, Flesca Manuel. "Contributions en simulation, expérimentation et modélisation destinées à l’analyse des instabilités de combustion hautes fréquences des moteurs fusées à ergols liquides." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC088/document.
This research concerns some of the issues raised by high frequency combustion instabilities in rocket engines. These instabilities are known to have detrimental effects leading, in some cases, to the destruction of the propulsion system. To avoid the appearance of such instabilities it is important to gain an understanding of the processes driving such dynamical phenomena. One has to consider the complex coupling between injection, combustion and the acoustic resonances of the system. The present work contributes to this objective by developing three items.The first deals with numerical simulations of non-reactive and reactive jets submitted to different modulation conditions to understand the interaction between jets, flames and their environment. Numerical simulations of non-reactive round jets as well as more complex flames formed by coaxial injectors operating under transcritical conditions were carried out using large eddy simulation (LES) adapted to real gas situations by making use of the AVBP-RG flow solver. Round jets were submitted to transverse velocity fluctuations. It has been found that for all amplitudes and frequencies of modulation, the modulated jet is deformed and oscillates. This behavior can be represented by a model. The coaxial flames were submitted to mass flow rate and pressure modulation. For these cases it has been found that the modulation induces variations of the global heat release rate. A mathematical relationship between the modulated parameters and the heat release rate has been proposed.The second item includes experimental investigations. For this purpose a New Pressurized Coupled Cavities (NPCC) laboratory test rig has been developed. The possible coupling between the plenum and the thrust chamber was studied. A model, linking pressure and velocity fluctuations between the plenum and the thrust chamber, has been developed. The laboratory test rig was also used to gather some knowledge on the levels of damping and the damping coefficients could be determined.The last item of this document deals with the development of a reduced order dynamical model which includes some of the driving and damping mechanisms of high frequency combustion instabilities. This dynamical description was implemented in a high frequency stability code (STAHF). This code was used to examine a 87 MW liquid rocket engine (BKD operated at DLR, Germany) exhibiting high frequency oscillations. After the adjustment of some control parameters, STAHF was able to retrieve some the features observed in experiments carried out at DLR
Dauptain, Antoine. "Allumage des moteurs fusées cryotechniques." Toulouse, INPT, 2006. http://ethesis.inp-toulouse.fr/archive/00000343/.
Today, space launchers require cryotechnic rocket engines able to reignite during flight. The ignition phases in flight conditions are particularly critical and the development of restartable engines needs accurate and reliable tools. The present thesis develops a Large Eddy Simulation (LES) for the study of unsteady supersonic reactive flows. Several aspects are treated : chemical kinetics, auto-ignition and differential diffusion, numerical methods suited to supersonic flows and their discontinuities, combustion. Comparisons with experimental data on academic test cases validate the models, and give detailed insights into the auto-ignition process. Based on these achievements, LES of industrial configurations may be now envisaged, allowing the study of unsteady ignition regimes and the optimization of devices
Canteins, Gabriel. "Etude de la détonation continue rotative - Application à la propulsion." Phd thesis, Université de Poitiers, 2006. http://tel.archives-ouvertes.fr/tel-00124803.
Les observations expérimentales montrent l'existence d'un régime de fronts réactifs continus. Les études paramétriques sur le fonctionnement et la géométrie du moteur mettent en évidence la constance de ce régime de fronts. Leur nombre, constant en phase stationnaire, est généralement compris entre 1 et 8 selon les conditions d'essai, leur célérité évolue peu entre 1000 et 1300 m/s et le rapport de pression à travers les fronts est proche de 2 ou 3. Les caractéristiques de ce régime (pression, célérité) sont nettement inférieures aux propriétés des détonations Chapman – Jouguet principalement car le brassage du mélange frais avec les gaz brûlés dégrade ses propriétés réactives. La faisabilité du moteur à détonation continue a été démontrée mais ses performances devront faire l'objet d'autres études pour en préciser l'intérêt en propulsion.
Lechner, Valentin. "Experimental study of LOX/CH4 flames in rocket engines." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPAST040.
Using methane as a fuel in rocket engines would have many advantages but the combustion with pure oxygen at high pressure remains poorly understood. From a thermodynamic point of view, methane and oxygen share very similar critical point values, making it challenging to predict propellant mixing, flame anchoring, stability and structure. Moreover, when methane is injected in excess, aerosols can be produced, which can clog the lines, damage the turbine, and reduce the efficiency.Therefore, a thorough update of the knowledge of LOX/CH4 combustion is necessary. These challenges are tackled within the consortium composed of EM2C laboratory, ONERA, CNES, and ArianeGroup. Two test campaigns are carried out at the MASCOTTE facility from ONERA, aiming to study three central topics: the flame structure, wall heat transfers, and aerosol production. To this end, various experimental diagnostics are implemented simultaneously during high-pressure hot-fire tests.Various imaging diagnostics are implemented to analyze the flame structure and the dense liquid jets. Despite the acquisition difficulties encountered in these extreme conditions, the analyses reveal a complex flame structure. In the subcritical regime, atomization and evaporation mechanisms dominate. The flame is much more opened and longer than at higher pressures, where diffusive mixing mechanisms prevail. Characterizing flame anchoring remains a challenge. A water ice ring surrounding, and masking, the flame foot has been identified. Formation mechanisms are proposed, and a growth/destruction temporal cycle is highlighted. Its presence strongly affects flame visualizations, and may lead to misinterpretations of its topology.Laser-induced phosphorescence (LIP) is implemented for the first time at MASCOTTE. Various LIP methods exist, but they are not well suited to the MASCOTTE conditions: wide temperature range, thermal transients, and two-phase flow environment favoring laser absorption/diffusion. Therefore, a specific method, the Full Spectrum Fitting method (FSF method), has been developed. It exploits the spectral dependence on temperature, enabling instantaneous measurements from 100 to 900 K with a precision of 17 K, with no dependence on the laser excitation energy. A detailed data analysis highlights the predominant wall heat transfer modes, studies the influence of the operating points, and compares the experimental data with a wall heat transfer model, which is particularly well suited for deducing the convective properties of the flow.Three diagnostics are used to characterize aerosols. An intrusive probe samples particles and burnt gases downstream of the flame. The particles are sampled on TEM grids and analyzed by Transmission Electron Microscopy. Detailed images of the aerosol morphology reveal that the particles are soot. Combustion products are analyzed by gas chromatography. This makes it possible to identify soot precursor molecules such as benzene and acetylene. Soot are quantified temporally by laser extinction. A dedicated post-processing method is developed and various hypotheses are discussed to explain the spatial variations of the soot production downstream of the flame
Douasbin, Quentin. "Acoustic waves in combustion devices : interactions with flames and boundary conditions." Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/20204/7/douasbin_quentin.pdf.
Pérez, Roca Sergio. "Model-based robust transient control of reusable liquid-propellant rocket engines." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS017.
The current trend towards a more affordable access to space is materialising in reusable launchers and engines. From the control perspective, these reusable liquid-propellant rocket engines (LPRE) imply more demanding robustness requirements than expendable ones, mainly due to their multi-restart and thrust-modulation capabilities. Classically, the control system handles LPRE operation at a finite set of predefined points. That approach reduces their throttability domain to a narrow interval in which they are designed to be safe. Moreover, transient phases, which have a great impact on engine life, are not robustly operated. Hence, the goal of this work is to develop a control loop which is adapted to the whole set of operating phases, transient and steady-state, and which is robust to internal parametric variations. Several blocks have been developed to constitute the control loop: engine simulation, reference generation and controllers. First, simulators representative of the gas-generator-cycle engines were built. The purely thermo-fluid-dynamic modelling of the cycle was subsequently adapted to control, obtaining nonlinear state-space models. In these models, the influence of continuous control inputs (valve openings) and of discrete ones (igniters and starter activations) is considered within a simplified hybrid approach. The continuous sub-phase of the start-up transient is feedback controlled to track pre-computed reference trajectories. Beyond the start-up, throttling scenarios also present an end-state-tracking algorithm. A model-based control method, Model Predictive Control, has been applied in a linearised manner with robustness considerations to all these scenarios, in which a set of hard constraints must be respected. Tracking of pressure (thrust) and mixture-ratio operating points within the design envelope is achieved in simulation while respecting constraints. Robustness to variations in the parameters, which are checked to be predominant according to analyses, is also demonstrated. This framework paves the way to experimental validation via hardware-in-the-loop simulations or in test benches
Messineo, Jérôme. "Modélisation des instabilités hydrodynamiques dans les moteurs-fusées hybrides." Thesis, Toulouse, ISAE, 2016. http://www.theses.fr/2016ESAE0025/document.
Hybrid rocket motors combine solid and bi-liquid chemical propulsion technologies and associate asolid fuel and a liquid oxidizer in its classical configuration. This architecture offers several advantagesover liquid propulsion such as lower costs and a simplified architecture. The possibility of performingmultiple extinctions and re-ignitions and a good theoretical specific impulse is also an improvement inregard to solid propulsion. Hybrid engines also have improved safety and a lower environmental impactthan other chemical propulsion systems. As in all combustion chambers, hybrid engines suffer from pressure oscillations under specific operating conditions. These instabilities provoke thrust fluctuations that can damage the launcher and payloads.Various phenomena can induce the pressure oscillations observed in hybrid rocket engines.The objective of this thesis is to propose a model of hydrodynamics instabilities that appear in hybridengines. A new exploitation of the database available at ONERA, and unsteady 2D and 3D numericalsimulations were used for the modeling. The instabilities are provoked by the periodic formation ofvortices in the combustion chamber that generate pressure fluctuations when passing through the nozzlethroat. The originality of the model, which is based on the classical theory of vortices generation ina cavity, consists in taking into account the geometrical variations of the combustion chamber duringoperation. These variations have an effect on the flow velocity, on the recirculation area in the postchamberand on the vortices. Finally, several new firing tests of the hybrid engine HYCOM have beenperformed and compared to the model developed in this thesis
Lacaze, Guilhem. "Simulation aux Grandes Echelles de l'allumage de moteurs fusées cryotechniques." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2009. http://tel.archives-ouvertes.fr/tel-00429666.
Guven, Umut. "Simulation haute-fidélité de la combustion pour les moteurs-fusées." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR30/document.
Ignition is a key point in the design of liquid rocket engine (LRE), and it requires to take into account several distinct physical phenomena that constitute numerical challenges. The first point addressed during this thesis is the modeling and simulation using Large Eddy Simulation of a LRE igniter in a configuration close to VINCI rocket engine. The hot gases from the igniter, rich in oxygen, are delivered at supersonic speeds in a chamber filled with hydrogen. Such configuration creates under-expanded jets with multiple shock/shock or shock/flame interactions. A focus is done on the ignition process. The second point addressed is the modeling and simulation of high pressure H2/O2 combustion which occurs. In particular, the effects of non-ideal diffusion are studied through a 1D premixed flames and a 2D splitter plate configuration. An impact of modeling on the species produced and the temperature field is highlighted
Fichot, Florian. "Modélisation de l'allumage d'une flamme de diffusion turbulente : application aux moteurs-fusées cryotechniques." Châtenay-Malabry, Ecole centrale de Paris, 1994. http://www.theses.fr/1994ECAP0349.
Cheuret, François. "Instabilités thermo-acoustiques de combustion haute-fréquence dans les moteurs fusées." Phd thesis, Université de Provence - Aix-Marseille I, 2005. http://tel.archives-ouvertes.fr/tel-00011656.
Méry, Yoann. "Mécanismes d'instabilités de combustion haute-fréquence et application aux moteurs-fusées." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2010. http://www.theses.fr/2010ECAP0012.
This thesis presents a study of high frequency instabilities in rocket engines. This issue, which has plagued many engine development programs, is approached by three complementary viewpoints: experimental, theoretical, and numerical. First, experiments are carried out to identify the main processes involved and bring forth mechanisms taking place when an engine becomes unstable. To achieve this stage, a new modulator (the VHAM), capable of creating acoustic waves representative of what occurs in an actual engine, is designed and characterized. The second part of this thesis concern theoretical analysis. Two models are developed following the main conclusions of the experimental campaign: heat release oscillations are due to the transverse flames’ motion, and the phenomenon is triggered when droplets become small enough to be convected by the acoustic field. Using these models as a baseline, a numerical code (STAHF) is presented. Its purpose is to account for mechanisms identified previously for little computational cost. This code is validated on particularly responding situations observed during experiments. It is then shown that it can be used to study real scale rocket engines. The third point of view adopted to address the problem is numerical simulation. Full compressible LES is chosen to study the interaction between acoustics and combustion. A new combustion model for non-premixed flames with infinitely fast chemistry is presented and validated on a well documented flame (H3). It is then used to study the interaction between a transverse acoustic wave and the H3 flame. A comparison between the Rayleigh source term computed from the simulation and the one predicted by the theoretical model FAME is conducted eventually
Torres, Yohann. "Transferts énergétiques dans les canaux de refroidissement courbes de moteurs fusées." Valenciennes, 2008. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/a9497a55-9e08-4b37-b37b-844deb1601a6.
The materials of the combustion chamber wall of rocket engines have to withstand extreme thermal and mechanical loadings, which are managed by efficient cooling. For an optimal design of the cooling system, with minimal hydrodynamic losses, a precise knowledge of the heat transfer is required. The combustion chamber profile imposes some curvatures to the cooling channel, because they follow the nozzle profile of the combustion chamber. These curvatures create dynamical secondary flows inside the channel and bring heat flux modifications through the chamber walls. The experimental project EH3C (Electrical Heated Curved Cooling Channels) has been supported by the german space propulsion center (DLR) in the frame of this PhD. Two test specimens have been designed, manufactured and tested. The first specimen is a single straight cooling channel, presenting a high aspect ratio and the second one is curved, in order to enlighten the curvature effects on the heat transfer and the pressure losses. Numerical simulations have been provided to model the experiments
Dabireau, François. "Étude des transferts de chaleur aux parois dans les moteurs-fusées." Toulouse, INPT, 2002. http://www.theses.fr/2002INPT041H.
The extreme conditions for pressure and temperature in rocket-engines impose to carefully predict heat fluxes, both mean (for engine cycle determination) and instantaneous (for lifetime of the combustion chamber). In the present study these fluxes are estimated with numerical computations. For a better evaluation of the mean fluxes with RANS codes laws of the wall are developed to take into account the high compressibility of the fluid and the high wall temperature gradient. These models are evaluated with « a priori » tests, and on several academic and industrial configurations. The percentage of error on the nozzle heat flux calculation is of about 50% for a log law and of 15% for the models developed here. The maximum wall heat flux is due to H2/02 flame/wall interaction. Several configurations of interaction are computed using Direct Simulation codes. One and two dimensional mecanisms are investigated. It is shown that, when the chemistry is adapted, simple chemistry studies are adequate because the problem is thermically controlled. The impact of the pressure on the flame structure is quite different in premixed or diffusion combustion. The flame-wall distance is the leading parameter for maximum wall heat flux. Finally the wall can be locally submitted to very high fluxes. Under certain conditions the interaction may become quasi-steady with a stabilised non-zero wall heat flux
Rocchi, Jean-Philippe. "Simulations aux grandes échelles de la phase d'allumage dans un moteur fusée cryotechnique." Phd thesis, Toulouse, INPT, 2014. http://oatao.univ-toulouse.fr/14667/1/rocchi.pdf.
SALINAS, VAZQUEZ MARTIN. "Simulation des grandes échelles d'écoulements dans les canaux de refroidissement de moteur fusée." Grenoble INPG, 1999. http://www.theses.fr/1999INPG0185.
Dupays, Joël. "Contribution à l'étude du rôle de la phase condensée dans la stabilité d'un propulseur à propergol solide pour lanceur spatial." Toulouse, INPT, 1996. http://www.theses.fr/1996INPT063H.
Richecœur, Franck. "Expérimentations et simulations numériques des interactions entre modes acoustiques transverses et flammes cryotechniques." Châtenay-Malabry, Ecole Centrale de Paris, 2006. http://www.theses.fr/2006ECAP1023.
The general objective of this research is to contribute to the understanding of fundamental mechanisms leading to high frequency instabilities in liquid rocket engines. The process involves a tight coupling between combustion and transverse acoustic modes of the thrust chamber. This problem is investigated with a combination of experimental, numerical and modeling tools. Experiments are carried out on a model scale combustor comprising multiple coaxial injection units placed in a row and fed with liquid oxygen and gaseous methane. This experiment recreates some of the conditions prevailing in liquid rocket engines. The combustor was designed to allow a clear separation between the longitudinal and tranverse resonant modes. It is equipped with large windows providing optical access to the flames and with pressure transducers detecting fluctuations of this quantity in the chamber and in the propellant injection manifold. A toothed wheel modulator is used to periodically block an auxiliary nozzle and inject acoustic perturbations in the system. Digital imaging techniques are used to examine the flame dynamics. Systematic hot fire tests have been carried out at low (0. 9 MPa), intermediate (3 MPa) and high pressure (6 MPa) to determine conditions where the flame is the most receptive to transverse acoustic modulations. A remarkable level of response was observed in the low pressure experiments. The level of oscillation was in that case around 8 % of the mean pressure. The flame is strongly modified when the coupling takes place with the first transverse mode of the cavity, its spreading rate is augmented and its luminosity is increased. An intriguing reduction of the axial convection velocity is also observed with the high speed camera. Phase relations established between the pressure perturbations and the heat release in the chamber indicate that these two quantities feature similar spatial distributions. The intermediate pressure experiments carried out with a new injection head comprising 5 injectors at a higher rate of heat release indicate that the sharpness of resonance is reduced and that this can be attributed to a more intense level of temperature fluctuations in the system. Cold flow experiments were also carried out to examine the motion of injected streams of liquid oxygen and gaseous nitrogen when they are submitted to a resonant transverse acoustic excitation. These experiments are complemented with numerical calculations carried out in the large eddy simulation (LES) framework. LES is used to examine the motion of multiple cold jets submitted to a transverse modulation. The oscillation induces a collective motion and mixing is intensified. A model is developed to represent the filtered rate of burning allowing a description of nonpremixed flames controlling cryogenic combustion. Initial calculations are carried out in a realistic multiple injector configuration fed with gaseous reactants. Two problems are envisaged on the modeling level. The first aims at describing how heat release fluctuations can be generated by tranverse velocity perturbations. An expression is devised which depends on the transverse velocity perturbation and on the sign of its gradient and its consequences are investigated. It is shown in particular that the model retrieves the pattern of heat release observed in some early experiments. The second model deals with the influence of temperature fluctuations on the resonance characteristics of a system. Direct simulation and analysis based on the method of averaging indicates that the response amplitude and the resonance sharpness are diminished in the presence of fluctuations, a phenomenon which seems to have been overlooked in the past but may have practical consequences. The knowledge gathered in these studies is intended to provide guidelines for further developments of computational tools aimed at the prediction of instabilities. It can also serve to develop design methods which would avoid the phenomenon
Taieb, David. "Simulation numérique des écoulements turbulents dans les canaux de refroidissements : Application aux moteurs-fusées." Phd thesis, INSA de Rouen, 2010. http://tel.archives-ouvertes.fr/tel-00925522.
Jacquot, Cédric. "Transfert instationnaire de chaleur en échangeur récupérateur de moteur de fusée : simulation expérimentale en échangeur bitube." Nancy 1, 2007. http://docnum.univ-lorraine.fr/public/SCD_T_2007_0010_JACQUOT.pdf.
The present thesis is concerned by experimental study of gas-gas bitubular heat exchangers, submitted to transient conditions, for counter current and cocurrent configurations. The transient imposes conditions are respective to entrance temperature or mass flux from one of the system fluids. After a synthesis of the state of the art, a study of a bitubular heat exchanger is developed, with two different modelling approachs. The first one considers the heat exchanger system as a whole (lumped system analysis) : only entrance and exit state are concerned. In the second approach, the heat exchanger is modelled on a local point of view : the various local 1D sections are taken into account ; the transient heat exchanger response to the solicitation is reported relative to temperatures evolution, and also heat fluxes exchanged. The various exposed models allow to consider fluid temperatures, but also internal and external walls temperatures. It is shown that the temperature response of the system is obtained with a first order exponential model for the walls and the non perturbed fluid ; a two exponent model is necessary for the temperature of the perturbed fluid. So we observe that a specific time constant exist for each subsystem inside the HEX ; the biexponential model allows us to take account of the non ideality of the perturbation, and implies to introduce a transition parameter in place of time lag. This last notion currently used for liquid-liquid HEX has not been caracterized until now. The time lag does not appear in the models concerning perturbed fluid, and internal wall ; however this time lag is necessary to describe adequately the internal wall
Daou, Joe͏̈l. "Etude de la vaporisation-combustion des gouttes d'oxygène liquide (LOX) à haute pression." Aix-Marseille 1, 1994. http://www.theses.fr/1994AIX11026.
Herding, Gérald. "Analyse expérimentale de la combustion d'ergols cryogéniques." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0527.
Mouronval, Anne-Sophie. "Etude numérique des phénomènes aéroélastiques en aérodynamique supersonique. Application aux tuyères propulsives." Rouen, INSA, 2004. http://www.theses.fr/2004ISAM0002.
Deng, Tian. "LES combined with statistical models of spray formation closely to air-blast atomizer." Thesis, Ecully, Ecole centrale de Lyon, 2011. http://www.theses.fr/2011ECDL0037/document.
This thesis introduced an extension to stochastic approach for simulation of air-blast atomization closely to injector. This approach was previously proposed in publications of Gorokhovski with his PHD students. Our extension of this approach is as follows. In the framework of LES approach, the contribution of primary atomization zone is simulated as an immersed solid body with stochastic structure. The last one is defined by stochastic simulation of position-and-curvature of interface between the liquid and the gas. As it was done previously in this approach, the simulation of the interface position was based on statistical universalities of fragmentation under scaling symmetry. Additionally to this, we simulate the outwards normal to the interface, assuming its stochastic relaxation to isotropy along with propagation of spray in the down-stream direction. In this approach, the statistics of immersed body force plays role of boundary condition for LES velocity field, as well as for production of primary blobs, which are then tracked in the Lagrangian way. In this thesis, the inter-particle collisions in the primary atomisation zone are accounted also by analogy with standard kinetic approach for the ideal gas. The closure is proposed for the statistical temperature of droplets. The approach was assessed by comparison with measurements of Hong in his PHD. The results of computation showed that predicted statistics of the velocity and of the size in the spray at different distances from the center plane, at different distances from the nozzle orifice, at different inlet conditions (different gas velocity at constant gas-to-liquid momentum ratio, different gas-to-liquid momentum ratio) are relatively close to measurements. Besides, the specific role of recirculation zone in front of the liquid core was emphasized in the flapping of the liquid core and in the droplets production
Picard, Thierry. "Modelisation eulerienne-lagrangienne de la combustion d'ergols dans un moteur de fusee biliquide." Paris, ENMP, 1987. http://www.theses.fr/1987ENMP0035.
Plourde, Frédéric. "Structures turbulentes d'un écoulement segmenté à injection pariétale." Poitiers, 1994. http://www.theses.fr/1994POIT2329.
Rey, Cédric. "Interactions collectives dans les instabilités de combustion haute fréquence : application aux moteurs fusées à ergols liquides." Châtenay-Malabry, Ecole centrale de Paris, 2004. http://www.theses.fr/2004ECAP0927.
Ficuciello, Antonio. "Analyse des effets acoustiques à haute fréquence/haute intensité sur l'injection coaxiale : application aux moteurs-fusées." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMR106/document.
The context of this work relies to high frequency combustion instabilities in Liquid Rocket Engines (LRE). The present research focuses on the effects of high amplitude transverse acoustic fields on non-reactive coaxial injection. The acoustic response of injection domes is found to be dependent on the local properties of the acoustic field in the injection cavity. The modification of the atomization process, induced by the acoustic field, has been analyzed in single and multi-injection configurations. Experiments were performed from low to high Weber number atomization regimes. Three phenomena are observed: jet flattening, improvement of the atomization process and deviation. The combination of these phenomena in multi-injection configurations leads to a droplet clustering phenomenon. In the presence of combustion, such a clustering could lead to non-uniform heat release rate which can trigger or sustain combustion instabilities. A theoretical model based on non-linear acoustics has been developed, providing general expressions of radiation pressure and resulting radiation force, for spherical and cylindrical objects in standing and progressive wave field. The model has been successfully used to interpret and quantify experimental observations in liquid/gas, trans-critical/super-critical and gas/gas configurations and showed that the Helmholtz number α characterizing the acoustic field and the density ratio η characterizing the two media are two parameters of importance. The major conclusions are that the observed phenomena can be interpreted as resulting from non-linear acoustics, the key feature being the density ratio. It is claimed that the layer separating the two media, seen as an interface, does not need to be restricted only to a liquid/gas interface
Basset, Thierry. "Contribution à la modélisation des écoulements diphasiques et réactifs internes : application aux propulseurs à propergol solide." Aix-Marseille 1, 1997. http://www.theses.fr/1997AIX11049.
Zikikout, Souad. "Mécanismes d'instabilité de combustion dans un foyer à flammes non prémélangées simulant l'injection dans un moteur fusée cryogénique." Paris 11, 1988. http://www.theses.fr/1988PA112208.
Many combustion problems have to be adressed for the design of a cryogenic rocket engine. The most important questions are ignition, flame stabilisation, extinction, pressure oscillations at low and high frequencies. These different phenomena are studied in a model combustor simulating the injection and the combustion process of the Ariane 5 rocket engine. The design of the combustor is defined by dimensional analysis. The similarity criteria retained lead to a six non-premixed flames of air and propane or air and hydrogen. Ignition mechanisms are studied with high speed schlieren imaging. It is found that the flame is ignited at very low air mass flow rate and high equivalence ratio. C2, CH and OH radiation measurements provide information on the heat release in the reaction zone and allow a determination of the ignition time lag. These results can be used for comparisons with numerical models of non-premixed flames. Spectral analysis of both the acoustic and free radicals light emission signais detected for each operating conditions shows that combustion instabilities occur when the pressure fluctuations are coupled with the heat release. We identify two different instability modes : (1) an intense low frequency pressure oscillations at 230Hz with periodic combustion. Large velocity fluctuations are produced at the injection plane and lead to cyclic reaction initiation and quenching. The coupling between the heat release and the acoustics is shown to drive the fluctuations. A theoretical model is proposed to determine low frequency instability limits in such circumstances, (2) a low frequency instability at 360 Hz produced by the interaction between the different flames taking the form of intense collisions and leading to total extinction of one or several injectors. Mode selective excitation is used to drive high frequency transverse oscillations. A theoretical formulation of the acoustic forcing in the combustor without flow and free of chemical reaction provides results which are in satisfactory agreement with experimental data. With combustion and under selective excitation the flames exhibit striking features. A sinuous motion is set up. These observations suggest that the unsteady heat release can be expressed in terms of the velocity fluctuations at the inlet plane. An instability model with heat release is then developed and it relies on the combustion sensitivity to velocity fluctuations. The displacements produced by the transverse velocity at the dump increase the mixing and activate the heat release after a certain delay. It is found that the coupling between heat release and transverse velocity fluctuations requires the presence of two modes. This model gives a theoretical basis for the experimental study performed with excitation
Jourdanneau, Eric. "Modélisation du spectre du méthane chaud en vue du diagnostic de la température dans un moteur de fusée." Dijon, 2005. http://www.theses.fr/2005DIJOS029.
This thesis is devoted to the modeling of the Raman spectra of the molecule 12CH4. The first chapter points out the theoretical elements allowing the construction of the Hamiltonian and deals with the calculation of the Raman intensities. The chapter two presents the experiments we made and the Raman spectra obtained. We determine the parameters of the polarizability of the three first polyads of methane which are the dyad, the pentad and the octad. Lastly, the chapter three deals with the calculation of the broadening coefficients and of the relaxation rates between the levels of the molecule. We compare three methane/argon interaction potentials, one being of Lennard-Jones type, the two others coming from ab initio calculations. We confront finally the parameters determined in this study with high resolution Raman spectra obtained in our laboratory and with CARS spectra obtained from the Office National d'Etudes et de Recherches Aérospatiales (ONERA)
Beduneau, Jean-Luc. "Caractérisation expérimentale des flammes non-prémélangées H₂/O₂ : application aux cas des injecteurs coaxiaux de moteurs fusées." Rouen, INSA, 2001. http://www.theses.fr/2001ISAM0005.
Breton, Mélanie. "Détection de l'allumage d'un moteur-fusée à propergol solide avec une matrice linéaire de filtres holographiques et par diffraction conique." Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24914/24914.pdf.
Potier, Luc. "Large Eddy Simulation of the combustion and heat transfer in sub-critical rocket engines." Thesis, Toulouse, INPT, 2018. http://www.theses.fr/2018INPT0043/document.
Combustion in cryogenic engines is a complex phenomenon, involving either liquid or supercritical fluids at high pressure, strong and fast oxidation chemistry, and high turbulence intensity. Due to extreme operating conditions, a particularly critical issue in rocket engine is wall heat transfer which requires efficient cooling of the combustor walls. The concern goes beyond material resistance: heat fluxes extracted through the chamber walls may be reused to reduce ergol mass or increase the power of the engine. In expander-type engine cycle, this is even more important since the heat extracted by the cooling system is used to drive the turbo-pumps that feed the chamber in fuel and oxidizer. The design of rocket combustors requires therefore an accurate prediction of wall heat flux. To understand and control the physics at play in such combustor, the Large Eddy Simulation (LES) approach is an efficient and reliable numerical tool. In this thesis work, the objective is to predict wall fluxes in a subcritical rocket engine configuration by means of LES. In such condition, ergols may be in their liquid state and it is necessary to model liquid jet atomization, dispersion and evaporation.The physics that have to be treated in such engine are: highly turbulent reactive flow, liquid jet atomization, fast and strong kinetic chemistry and finally important wall heat fluxes. This work first focuses on several modeling aspects that are needed to perform the target simulations. H2/O2 flames are driven by a very fast chemistry, modeled with a reduced mechanism validated on academic configurations for a large range of operating conditions in laminar pre- mixed and non-premixed flames. To form the spray issued from the atomization of liquid oxygen (LOx) an injection model is proposed based on empirical correlations. Finally, a wall law is employed to recover the wall fluxes without resolving directly the boundary layer. It has been specifically developed for important temperature gradients at the wall and validated on turbulent channel configurations by comparison with wall resolved LES. The above models are then applied first to the simulation of the CONFORTH sub-scale thrust chamber. This configuration studied on the MASCOTTE test facility (ONERA) has been measured in terms of wall temperature and heat flux. The LES shows a good agreement compared to experiment, which demonstrates the capability of LES to predict heat fluxes in rocket combustion chambers. Finally, the JAXA experiment conducted at JAXA/Kakuda space center to observe heat transfer enhancement brought by longitudinal ribs along the chamber inner walls is also simulated with the same methodology. Temperature and wall fluxes measured with smooth walls and ribbed walls are well recovered by LES. This confirms that the LES methodology proposed in this work is able to handle wall fluxes in complex geometries for rocket operating conditions
Deck, Sébastien. "Simulation numérique des charges latérales instationnaires sur des configurations de lanceur." Orléans, 2002. http://www.theses.fr/2002ORLE2017.
De, Benedictis Massimiliano. "Instabilités couplées à haute fréquence dans les moteurs - fusées à ergols liquides : étude du couplage chambre de combustion - système d'alimentation." Phd thesis, Université de Poitiers, 2007. http://tel.archives-ouvertes.fr/tel-00283229.
Boisneau, Olivier. "Étude du comportement de gouttes dans un champ acoustique intense : applications aux instabilités de combustion HF dans les moteurs-fusées." Toulouse, ENSAE, 2003. http://www.theses.fr/2003ESAE0023.
Alleaume, Virginie. "Etude expérimentale du transitoire de remplissage dans un moteur fusée en présence de transferts thermiques aux parois et du gaz de balayage." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAI024.
In order to control the ignition of rocket motors during ballistic flight, the transient flow of comburant into a reservoir or buffer cavity (dôme) and then through a grid of injectors must be carefully characterised. The liquid oxygen is held under pressure upstream of a valve which opens into the dome. The valve opening is a control parameter. To avoid any possible flow of carburant from combustion chamber back into reservoir, the latter is swept with an inert gas, thus ensuring that the pressure in the reservoir remains higher than in the combustion chamber. This experimental study has the aim of characterising the spatio-temporal structure of two-phase flow into the dome following opening of principal liquid valve. Filling the dome and forcing the liquid through the injectors has an overall time scale of some hundred milliseconds. High resolution measurements of liquid and gas flow rates, pressure, phase distribution, interface velocity and temperatures are recorded for different values of the key parameters as well as visualisations. For the experimental program with heat transfer, the comburant was replaced with "x". Much work was carried out on the effects of heat transfer from either the gas or the walls or both to the liquid entering the dome once these were above the liquid boiling point. Previous studies in the LEGI using water and air, and without heat transfer brought to light the important variations in dome pressure and liquid flow rate during the transient, while analysis of results indicated the importance of a number of time scales : value opening time, time for the liquid to cover the injectors, time to fill the dome, time to empty it. For the heat transfer experiments, the walls are heated for the pressure range chosen. The sweep gas is heated too. The aim of these experiments is to seek evidence of a phase-change at the walls or during interaction with the gas and to evaluate its importance. To carry out these experiments, specific instrumentation was used. The whole of these mesures enable us to understand the transient filling of the injection cavity. Thus, theoretical analysis have to allow extrapolations of results obteined in laboratory to real cases (cryogenic liquid under microgravity). Then, we have to give a data base to developp and validate numerical simulation