Дисертації з теми "Moteur fusée cryotechnique"
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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.
Bodèle, Emmanuel. "Modélisation et simulation de l'atomisation secondaire et de la vaporisation turbulente : application à la combustion cryotechnique." Phd thesis, Université d'Orléans, 2004. http://tel.archives-ouvertes.fr/tel-00283103.
Ces modèles sont issus d'études expérimentales précédentes du LCSR, ayant permis d'établir des bases de données.
Les calculs sont basés sur la simulation du banc d'essai MASCOTTE (Montage Autonome Simplifié pour la Cryocombustion dans l'Oxygène et Toutes Techniques Expérimentales) de l'ONERA. Les résultats montrent d'une part l'influence de l'atomisation sur la structure du brouillard et de la flamme. D'autre part, les simulations de la vaporisation turbulente mettent en évidence l'influence de la turbulence sur les propriétés des gouttes.
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
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
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
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.
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.
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.
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.
Juniper, Matthew. "Structure et stabilisation des flammes cryotechniques." Châtenay-Malabry, Ecole centrale de Paris, 2001. http://www.theses.fr/2001ECAP0728.
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
Herding, Gérald. "Analyse expérimentale de la combustion d'ergols cryogéniques." Châtenay-Malabry, Ecole centrale de Paris, 1997. http://www.theses.fr/1997ECAP0527.
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
Barbeau, Bertrand. "Modélisation de la combustion diphasique en vue de la simulation d'un injecteur cryotechnique." Châtenay-Malabry, Ecole centrale de Paris, 1999. http://www.theses.fr/1999ECAP0617.
Porcheron, Emmanuel. "Atomisation d'un jet liquide par un jet de gaz inerte appliquée à la propulsion cryotechnique." Poitiers, 1998. http://www.theses.fr/1998POIT2300.
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.
Sarotte, Camille. "Improvement of monitoring and reconfiguration processes for liquid propellant rocket engine." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS348/document.
Monitoring and improving the operating modes of launcher propulsion systems are major challenges in the aerospace industry. A failure or malfunction of the propulsion system can have a significant impact for institutional or private customers and results in environmental or human catastrophes. Health Management Systems (HMS) for liquid propellant rocket engines (LPREs), have been developed to take into account the current challenges by addressing safety and reliability issues. Their objective was initially to detect failures or malfunctions, isolate them and take a decision using Redlines and Expert Systems. However, those methods can induce false alarms or undetected failures that can be critical for the operation safety and reliability. Hence, current works aim at eliminating some catastrophic failures but also to mitigate benign shutdowns to non-shutdown actions. Since databases are not always sufficient to use efficiently data-based analysis methods, model-based methods are essentially used. The first task is to detect component and / or instrument failures with Fault Detection and Isolation (FDI) approaches. If the failure is minor, non-shutdown actions must be defined to maintain the overall system current performances close to the desirable ones and preserve stability conditions. For this reason, it is required to perform a robust (uncertainties, unknown disturbances) reconfiguration of the engine. Input saturation should also be considered in the control law design since unlimited control signals are not available due to physical actuators characteristics or performances. The three objectives of this thesis are therefore: the modeling of the different main subsystems of a LPRE, the development of FDI algorithms from the previously developed models and the definition of a real-time engine reconfiguration system to compensate for certain types of failures. The developed FDI and Reconfiguration (FDIR) scheme based on those three objectives has then been validated with the help of simulations with CARINS (CNES) and the MASCOTTE test bench (CNES/ONERA)
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.
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