Computational study on the non-reacting flow in Lean Direct Injection gas turbine combustors through Eulerian-Lagrangian Large-Eddy Simulations

[ES] El principal desafío en los motores turbina de gas empleados en aviación reside en aumentar la eficiencia del ciclo termodinámico manteniendo las emisiones contaminantes por debajo de las rigurosas restricciones. Ésto ha conllevado la necesidad de diseñar nuevas estrategias de inyección/combustión que operan en puntos de operación peligrosos por su cercanía al límite inferior de apagado de llama. En este contexto, el concepto Lean Direct Injection (LDI) ha emergido como una tecnología prometedora a la hora de reducir los óxidos de nitrógeno (NOx) emitidos por las plantas propulsoras de los aviones de nueva generación. En este contexto, la presente tesis tiene como objetivos contribuir al conocimiento de los mecanismos físicos que rigen el comportamiento de un quemador LDI y proporcionar herramientas de análisis para una profunda caracterización de las complejas estructuras de flujo de turbulento generadas en el interior de la cámara de combustión. Para ello, se ha desarrollado una metodología numérica basada en CFD capaz de modelar el flujo bifásico no reactivo en el interior de un quemador LDI académico mediante enfoques de turbulencia U-RANS y LES en un marco Euleriano-Lagrangiano. La resolución numérica de este problema multi-escala se aborda mediante la descripción completa del flujo a lo largo de todos los elementos que constituyen la maqueta experimental, incluyendo su paso por el swirler y entrada a la cámara de combustión. Ésto se lleva a cabo través de dos códigos CFD que involucran dos estrategias de mallado diferentes: una basada en algoritmos de generación y refinamiento automático de la malla (AMR) a través de CONVERGE y otra técnica de mallado estático más tradicional mediante OpenFOAM. Por un lado, se ha definido una metodología para obtener una estrategia de mallado óptima mediante el uso del AMR y se han explotado sus beneficios frente a los enfoques tradicionales de malla estática. De esta forma, se ha demostrado que la aplicabilidad de las herramientas de control de malla disponibles en CONVERGE como el refinamiento fijo (fixed embedding) y el AMR son una opción muy interesante para afrontar este tipo de problemas multi-escala. Los resultados destacan una optimización del uso de los recursos computacionales y una mayor precisión en las simulaciones realizadas con la metodología presentada. Por otro lado, el uso de herramientas CFD se ha combinado con la aplicación de técnicas de descomposición modal avanzadas (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificación numérica de los principales modos acústicos en la cámara de combustión ha demostrado el potencial de estas herramientas al permitir caracterizar las estructuras de flujo coherentes generadas como consecuencia de la rotura de los vórtices (VBB) y de los chorros fuertemente torbellinados presentes en el quemador LDI. Además, la implementación de estos procedimientos matemáticos ha permitido tanto recuperar información sobre las características de la dinámica de flujo como proporcionar un enfoque sistemático para identificar los principales mecanismos que sustentan las inestabilidades en la cámara de combustión. Finalmente, la metodología validada ha sido explotada a través de un Diseño de Experimentos (DoE) para cuantificar la influencia de los factores críticos de diseño en el flujo no reactivo. De esta manera, se ha evaluado la contribución individual de algunos parámetros funcionales (el número de palas del swirler, el ángulo de dichas palas, el ancho de la cámara de combustión y la posición axial del orificio del inyector) en los patrones del campo fluido, la distribución del tamaño de gotas del combustible líquido y la aparición de inestabilidades en la cámara de combustión a través de una matriz ortogonal L9 de Taguchi. Este estudio estadístico supone un punto de partida para posteriores estudios de inyección, atomización y combus[CA] El principal desafiament als motors turbina de gas utilitzats a la aviació resideix en augmentar l'eficiència del cicle termodinàmic mantenint les emissions contaminants per davall de les rigoroses restriccions. Aquest fet comporta la necessitat de dissenyar noves estratègies d'injecció/combustió que radiquen en punts d'operació perillosos per la seva aproximació al límit inferior d'apagat de flama. En aquest context, el concepte Lean Direct Injection (LDI) sorgeix com a eina innovadora a l'hora de reduir els òxids de nitrogen (NOx) emesos per les plantes propulsores dels avions de nova generació. Sota aquest context, aquesta tesis té com a objectius contribuir al coneixement dels mecanismes físics que regeixen el comportament d'un cremador LDI i proporcionar ferramentes d'anàlisi per a una profunda caracterització de les complexes estructures de flux turbulent generades a l'interior de la càmera de combustió. Per tal de dur-ho a terme s'ha desenvolupat una metodología numèrica basada en CFD capaç de modelar el flux bifàsic no reactiu a l'interior d'un cremador LDI acadèmic mitjançant els enfocaments de turbulència U-RANS i LES en un marc Eulerià-Lagrangià. La resolució numèrica d'aquest problema multiescala s'aborda mitjançant la resolució completa del flux al llarg de tots els elements que constitueixen la maqueta experimental, incloent el seu pas pel swirler i l'entrada a la càmera de combustió. Açò es duu a terme a través de dos codis CFD que involucren estratègies de mallat diferents: una basada en la generación automàtica de la malla i en l'algoritme de refinament adaptatiu (AMR) amb CONVERGE i l'altra que es basa en una tècnica de mallat estàtic més tradicional amb OpenFOAM. D'una banda, s'ha definit una metodologia per tal d'obtindre una estrategia de mallat òptima mitjançant l'ús de l'AMR i s'han explotat els seus beneficis front als enfocaments tradicionals de malla estàtica. D'aquesta forma, s'ha demostrat que l'aplicabilitat de les ferramente de control de malla disponibles en CONVERGE com el refinament fixe (fixed embedding) i l'AMR són una opció molt interessant per tal d'afrontar aquest tipus de problemes multiescala. Els resultats destaquen una optimització de l'ús dels recursos computacionals i una major precisió en les simulacions realitzades amb la metodologia presentada. D'altra banda, l'ús d'eines CFD s'ha combinat amb l'aplicació de tècniques de descomposició modal avançades (Proper Orthogonal Decomposition and Dynamic Mode Decomposition). La identificació numèrica dels principals modes acústics a la càmera de combustió ha demostrat el potencial d'aquestes ferramentes al permetre caracteritzar les estructures de flux coherents generades com a conseqüència del trencament dels vòrtex (VBB) i dels raigs fortament arremolinats presents al cremador LDI. A més, la implantació d'estos procediments matemàtics ha permès recuperar informació sobre les característiques de la dinàmica del flux i proporcionar un enfocament sistemàtic per tal d'identificar els principals mecanismes que sustenten les inestabilitats a la càmera de combustió. Finalment, la metodologia validada ha sigut explotada a traves d'un Diseny d'Experiments (DoE) per tal de quantificar la influència dels factors crítics de disseny en el flux no reactiu. D'aquesta manera, s'ha avaluat la contribución individual d'alguns paràmetres funcionals (el nombre de pales del swirler, l'angle de les pales, l'amplada de la càmera de combustió i la posició axial de l'orifici de l'injector) en els patrons del camp fluid, la distribució de la mida de gotes del combustible líquid i l'aparició d'inestabilitats en la càmera de combustió mitjançant una matriu ortogonal L9 de Taguchi. Aquest estudi estadístic és un bon punt de partida per a futurs estudis de injecció, atomització i combustió en cremadors LDI.[EN] Aeronautical gas turbine engines present the main challenge of increasing the efficiency of the cycle while keeping the pollutant emissions below stringent restrictions. This has led to the design of new injection-combustion strategies working on more risky and problematic operating points such as those close to the lean extinction limit. In this context, the Lean Direct Injection (LDI) concept has emerged as a promising technology to reduce oxides of nitrogen (NOx) for next-generation aircraft power plants In this context, this thesis aims at contributing to the knowledge of the governing physical mechanisms within an LDI burner and to provide analysis tools for a deep characterisation of such complex flows. In order to do so, a numerical CFD methodology capable of reliably modelling the 2-phase nonreacting flow in an academic LDI burner has been developed in an Eulerian-Lagrangian framework, using the U-RANS and LES turbulence approaches. The LDI combustor taken as a reference to carry out the investigation is the laboratory-scale swirled-stabilised CORIA Spray Burner. The multi-scale problem is addressed by solving the complete inlet flow path through the swirl vanes and the combustor through two different CFD codes involving two different meshing strategies: an automatic mesh generation with adaptive mesh refinement (AMR) algorithm through CONVERGE and a more traditional static meshing technique in OpenFOAM. On the one hand, a methodology to obtain an optimal mesh strategy using AMR has been defined, and its benefits against traditional fixed mesh approaches have been exploited. In this way, the applicability of grid control tools available in CONVERGE such as fixed embedding and AMR has been demonstrated to be an interesting option to face this type of multi-scale problem. The results highlight an optimisation of the use of the computational resources and better accuracy in the simulations carried out with the presented methodology. On the other hand, the use of CFD tools has been combined with the application of systematic advanced modal decomposition techniques (i.e., Proper Orthogonal Decomposition and Dynamic Mode Decomposition). The numerical identification of the main acoustic modes in the chamber have proved their potential when studying the characteristics of the most powerful coherent flow structures of strongly swirled jets in a LDI burner undergoing vortex breakdown (VBB). Besides, the implementation of these mathematical procedures has allowed both retrieving information about the flow dynamics features and providing a systematic approach to identify the main mechanisms that sustain instabilities in the combustor. Last, this analysis has also allowed identifying some key features of swirl spray systems such as the complex pulsating, intermittent and cyclical spatial patterns related to the Precessing Vortex Core (PVC). Finally, the validated methodology is exploited through a Design of Experiments (DoE) to quantify the influence of critical design factors on the non-reacting flow. In this way, the individual contribution of some functional parameters (namely the number of swirler vanes, the swirler vane angle, the combustion chamber width and the axial position of the nozzle tip) into both the flow field pattern, the spray size distribution and the occurrence of instabilities in the combustion chamber are evaluated throughout a Taguchi's orthogonal array L9. Such a statistical study has supposed a good starting point for subsequent studies of injection, atomisation and combustion on LDI burners.Belmar Gil, M. (2020). Computational study on the non-reacting flow in Lean Direct Injection gas turbine combustors through Eulerian-Lagrangian Large-Eddy Simulations [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159882TESI

Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion

[EN] In this paper, a one-dimensional computational model of the flow in a common-rail injector is used to compute local variations of fuel temperature (including the temperature change produced upon expansion across the nozzle) and analyse their effect on injector dynamics. These variations are accounted through the adiabatic flow hypothesis, assessed in a first part of the paper where the model features are also described. They imply variations in the fuel properties and the flow regime established across the injector internal restrictions driving the solenoid valve. An extensive validation of the model against experimental results is presented for a wide range of conditions. Multiple injection strategies are also explored, analysing the influence of the inlet fuel temperature and its variations on the mass injected by successive injections and the critical dwell time below which they cannot be separated. Results show significant changes in fuel temperature across some injector restrictions. These changes are greater the higher the rail pressure and lower the fuel temperature at the injector inlet. In the case of the flow across nozzle orifices, the fuel can be either heated or subcooled depending on the operating conditions, the heating being especially relevant for cold-start-like fuel temperatures at the inlet. Thermal effects also influence the injection rate and duration. This influence on injector dynamics is particularly accused in the injector of study due to its ballistic nature. In this regard, the time needed to effectively separate two successive injections is greater the higher the fuel temperature and the injection pressure.This work was partly sponsored by FEDER and the Spanish "Ministerio de Economia y Competitividad" in the frame of the project "Desarrollo de modelos de combustion y emisiones HPC para el analisis de plantas propulsivas de transporte sostenible (CHEST)", reference TRA2017-89139-C2-1-R-AR. On the other hand, the support given to Mr Mario Belmar by "Universitat Politecnica de Valencia" through the "FPI-Subprograma 2" grant within the "Programa de Apoyo para la Investigacion y Desarrollo (PAID-01-18)" is gratefully acknowledged by the authors.Payri, R.; Salvador, FJ.; Carreres, M.; Belmar-Gil, M. (2020). Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion. Fuel. 260:1-17. https://doi.org/10.1016/j.fuel.2019.115663S117260Gumus, M., Sayin, C., & Canakci, M. (2012). The impact of fuel injection pressure on the exhaust emissions of a direct injection diesel engine fueled with biodiesel–diesel fuel blends. Fuel, 95, 486-494. doi:10.1016/j.fuel.2011.11.020Agarwal, A. K., Dhar, A., Gupta, J. G., Kim, W. I., Choi, K., Lee, C. S., & Park, S. (2015). Effect of fuel injection pressure and injection timing of Karanja biodiesel blends on fuel spray, engine performance, emissions and combustion characteristics. Energy Conversion and Management, 91, 302-314. doi:10.1016/j.enconman.2014.12.004Zecca, A., & Chiari, L. (2010). Fossil-fuel constraints on global warming. Energy Policy, 38(1), 1-3. doi:10.1016/j.enpol.2009.06.068Wang, J., Feng, L., Tang, X., Bentley, Y., & Höök, M. (2017). The implications of fossil fuel supply constraints on climate change projections: A supply-side analysis. Futures, 86, 58-72. doi:10.1016/j.futures.2016.04.007Wang, X., Huang, Z., Zhang, W., Kuti, O. A., & Nishida, K. (2011). Effects of ultra-high injection pressure and micro-hole nozzle on flame structure and soot formation of impinging diesel spray. Applied Energy, 88(5), 1620-1628. doi:10.1016/j.apenergy.2010.11.035Boccardo, G., Millo, F., Piano, A., Arnone, L., Manelli, S., Fagg, S., … Weber, J. (2019). Experimental investigation on a 3000 bar fuel injection system for a SCR-free non-road diesel engine. Fuel, 243, 342-351. doi:10.1016/j.fuel.2019.01.122Mancaruso, E., Sequino, L., & Vaglieco, B. M. (2016). Analysis of the pilot injection running Common Rail strategies in a research diesel engine by means of infrared diagnostics and 1d model. Fuel, 178, 188-201. doi:10.1016/j.fuel.2016.03.066Breda, S., D’Orrico, F., Berni, F., d’ Adamo, A., Fontanesi, S., Irimescu, A., & Merola, S. S. (2019). Experimental and numerical study on the adoption of split injection strategies to improve air-butanol mixture formation in a DISI optical engine. Fuel, 243, 104-124. doi:10.1016/j.fuel.2019.01.111Wang, B., Pamminger, M., Vojtech, R., & Wallner, T. (2018). Impact of injection strategies on combustion characteristics, efficiency and emissions of gasoline compression ignition operation in a heavy-duty multi-cylinder engine. International Journal of Engine Research, 21(8), 1426-1440. doi:10.1177/1468087418801660Sun, Z.-Y., Li, G.-X., Chen, C., Yu, Y.-S., & Gao, G.-X. (2015). Numerical investigation on effects of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle for a high-pressure common-rail DI diesel engine. Energy Conversion and Management, 89, 843-861. doi:10.1016/j.enconman.2014.10.047Torelli, R., Som, S., Pei, Y., Zhang, Y., & Traver, M. (2017). Influence of fuel properties on internal nozzle flow development in a multi-hole diesel injector. Fuel, 204, 171-184. doi:10.1016/j.fuel.2017.04.123Salvador, F., De la Morena, J., Crialesi-Esposito, M., & Martínez-López, J. (2017). Comparative study of the internal flow in diesel injection nozzles at cavitating conditions at different needle lifts with steady and transient simulations approaches. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 232(8), 1060-1078. doi:10.1177/0954407017725672Ihme, M., Ma, P. C., & Bravo, L. (2018). Large eddy simulations of diesel-fuel injection and auto-ignition at transcritical conditions. International Journal of Engine Research, 20(1), 58-68. doi:10.1177/1468087418819546Desantes, J. M., Salvador, F. J., Carreres, M., & Martínez-López, J. (2014). Large-eddy simulation analysis of the influence of the needle lift on the cavitation in diesel injector nozzles. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 229(4), 407-423. doi:10.1177/0954407014542627Payri, R., Salvador, F. J., Carreres, M., & De la Morena, J. (2016). Fuel temperature influence on the performance of a last generation common-rail diesel ballistic injector. Part II: 1D model development, validation and analysis. Energy Conversion and Management, 114, 376-391. doi:10.1016/j.enconman.2016.02.043Salvador, F. J., Carreres, M., Crialesi-Esposito, M., & Plazas, A. H. (2017). Determination of critical operating and geometrical parameters in diesel injectors through one dimensional modelling, design of experiments and an analysis of variance. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 232(13), 1762-1781. doi:10.1177/0954407017735262Desantes, J., Salvador, F., Carreres, M., & Jaramillo, D. (2015). Experimental Characterization of the Thermodynamic Properties of Diesel Fuels Over a Wide Range of Pressures and Temperatures. SAE International Journal of Fuels and Lubricants, 8(1), 190-199. doi:10.4271/2015-01-0951Dernotte, J., Hespel, C., Houille, S., Foucher, F., & Mounaim-Rousselle, C. (2012). INFLUENCE OF FUEL PROPERTIES ON THE DIESEL INJECTION PROCESS IN NONVAPORIZING CONDITIONS. Atomization and Sprays, 22(6), 461-492. doi:10.1615/atomizspr.2012004401Park, Y., Hwang, J., Bae, C., Kim, K., Lee, J., & Pyo, S. (2015). Effects of diesel fuel temperature on fuel flow and spray characteristics. Fuel, 162, 1-7. doi:10.1016/j.fuel.2015.09.008Wang, Z., Ding, H., Wyszynski, M. L., Tian, J., & Xu, H. (2015). Experimental study on diesel fuel injection characteristics under cold start conditions with single and split injection strategies. Fuel Processing Technology, 131, 213-222. doi:10.1016/j.fuproc.2014.10.003Salvador, F. J., Gimeno, J., Carreres, M., & Crialesi-Esposito, M. (2017). Experimental assessment of the fuel heating and the validity of the assumption of adiabatic flow through the internal orifices of a diesel injector. Fuel, 188, 442-451. doi:10.1016/j.fuel.2016.10.061Nurick, W. H. (1976). Orifice Cavitation and Its Effect on Spray Mixing. Journal of Fluids Engineering, 98(4), 681-687. doi:10.1115/1.3448452Soteriou C, Andrews R, Smith M. Direct injection diesel sprays and the effect of cavitation and hydraulic flip on atomization. SAE Pap 950080 1995. doi: 10.4271/950080.Lichtarowicz, A., Duggins, R. K., & Markland, E. (1965). Discharge Coefficients for Incompressible Non-Cavitating Flow through Long Orifices. Journal of Mechanical Engineering Science, 7(2), 210-219. doi:10.1243/jmes_jour_1965_007_029_02Franc J-P. The Rayleigh-Plesset equation: a simple and powerful tool to understand various aspects of cavitation. Fluid Dyn. Cavitation Cavitating Turbopumps, vol. 496, Vienna: Springer; 2007, p. 1–41. doi: 10.1007/978-3-211-76669-9_1.PAYRI, R., GARCIA, J., SALVADOR, F., & GIMENO, J. (2005). Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel, 84(5), 551-561. doi:10.1016/j.fuel.2004.10.009Salvador, F. J., Gimeno, J., Carreres, M., & Crialesi-Esposito, M. (2016). Fuel temperature influence on the performance of a last generation common-rail diesel ballistic injector. Part I: Experimental mass flow rate measurements and discussion. Energy Conversion and Management, 114, 364-375. doi:10.1016/j.enconman.2016.02.042Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). A NEW METHODOLOGY FOR CORRECTING THE SIGNAL CUMULATIVE PHENOMENON ON INJECTION RATE MEASUREMENTS. Experimental Techniques, 32(1), 46-49. doi:10.1111/j.1747-1567.2007.00188.xTheodorakakos, A., Strotos, G., Mitroglou, N., Atkin, C., & Gavaises, M. (2014). Friction-induced heating in nozzle hole micro-channels under extreme fuel pressurisation. Fuel, 123, 143-150. doi:10.1016/j.fuel.2014.01.050Strotos, G., Koukouvinis, P., Theodorakakos, A., Gavaises, M., & Bergeles, G. (2015). Transient heating effects in high pressure Diesel injector nozzles. International Journal of Heat and Fluid Flow, 51, 257-267. doi:10.1016/j.ijheatfluidflow.2014.10.010Salvador, F. J., Carreres, M., De la Morena, J., & Martínez-Miracle, E. (2018). Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles. Energy Conversion and Management, 171, 438-451. doi:10.1016/j.enconman.2018.05.102Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). Effect of fuel properties on diesel spray development in extreme cold conditions. 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Influence of key geometrical features on the non-reacting flow of a Lean Direct Injection (LDI) combustor through Large-Eddy Simulation and a Design of Experiments

[EN] Lean Direct Injection (LDI) emerged as an interesting concept to limit NOx emissions in aero engines at the cost of operating close to the flame lean blow-off limit. In this technology, fuel is injected into a swirled airstream that generates recirculating flow structures that stabilize the flame. It is then of paramount importance at the design stage to understand the effect of various features on these structures. The present investigation makes use of Eulerian-Lagrangian Large-Eddy Simulations (LES) previously validated against existing experimental data for a reference condition to study the liquid non-reacting flow inside the CORIA Spray LDI burner with the help of Adaptive Mesh Refinement (AMR). A Design of Experiments (DoE) is proposed to analyze the significance of several geometrical features on the flow field, namely the combustor width, the air swirler vane angle, the number of swirler vanes and the axial location of the fuel injector tip. The study covers the qualitative appearance of the flow and the quantitative characterization of the spray dispersion and fuel-air mixing process. In this way, the chosen response variables include the size of the relevant coherent flow structures (Central Toroidal Recirculation Zone induced by the Vortex Breakdown Bubble, Corner Recirculation Zone and Swirled Jet) and their associated velocities, spray features (global drop sizes and spray penetration), pressure drop across the swirler and induced swirl number. Besides, the Precessing Vortex Core (PVC) relevance and frequency content is studied through Proper Orthogonal Decomposition (POD). Results from the statistical analysis show that the number of swirler vanes and their angle are the geometrical parameters that most importantly influence the flow features: stronger recirculation zones leading to an improved atomization and mixing have been found both when decreasing the number of swirler blades and increasing the blade angle. However, both solutions also increase the pressure losses across the swirler. As far as the spectral analysis is concerned, the number of swirler vanes is the most influencing factor on both the frequency and intensity of the PVC modes, being crucial for the possible activation and the energetic content of a double-helix PVC mode.This work was partly sponsored by Grant No. PID2019- 109952RB-I00 Contribución a la aviación sostenible a través de la optimización numérica de cámaras con combustión pobre para aeromotores de nueva generación más silenciosos y limpios (QUILECOM) funded by MCIN/AEI/10.13039/501100011033. The authors thankfully acknowledge the computer resources at Altamira (RES-IM-2020-1-0018) and MareNostrum (RES-IM-2020-2-0009) in the frame of the Spanish Supercomputing Network. Additionally, the support given to Mr. Mario Belmar by Universitat Politècnica de València through the FPI-Subprograma 2 grant within the Programa de Apoyo para la Investigación y Desarrollo (PAID-01-18) is gratefully acknowledged. The authors would also like to thank Prof. Francisco Javier Salvador for the fruitful discussions on the DoE and the selection of Taguchi arrays and Ms. Alicia Muñoz for her help and support modifying the computational domain geometries.Carreres, M.; Garcia Tiscar, J.; Belmar-Gil, M.; Cervelló-Sanz, D. (2022). Influence of key geometrical features on the non-reacting flow of a Lean Direct Injection (LDI) combustor through Large-Eddy Simulation and a Design of Experiments. Aerospace Science and Technology. 126. https://doi.org/10.1016/j.ast.2022.10763410763412

Internal Numerical Simulation of a Swirl Simplex Atomizer to Predict Atomization Outputs

International audienc

Diseño y análisis CFD de un ala de avión comercial subsónico

[ES] El principal objetivo de este trabajo es diseñar un ala para una aeronave de la que se conocen las especificaciones iniciales y comprobar mediante un análisis CFD que produce las prestaciones necesarias para mantener la aeronave en el aire durante su fase de vuelo en crucero.Belmar Gil, M. (2014). Diseño y análisis CFD de un ala de avión comercial subsónico. http://hdl.handle.net/10251/178770Archivo delegad

Estudio computacional del flujo no reactivo en cámaras de combustión

El presente Trabajo Fin de Master trata la resolución numérica mediante códigos CFD de una novedosa estrategia de inyección/combustión, conocida como Lean Direct Injection, aplicada a los motores de flujo continuo. Este nuevo concepto surge como reacción a las cada vez más estrictas regulaciones de emisiones contaminantes, especialmente NOx, impuestas por los organismos pertinentes (Comité en Protección Ambiental en Aviación, CAEP). El estudio de la inyección de combustible, atomización y posterior evaporación e interacción con el flujo turbulento presente en la cámara de combustión resulta de vital importancia para determinar la eficiencia global y las emisiones vinculadas al motor. Este documento pretende establecer una base sólida previa a dicho estudio, mediante la resolución de un flujo premezclado no reactivo que permita caracterizar la estructura del campo de velocidades turbulento formada por el aire en la cual se inyectará posteriormente el combustible. Para ello se toma como referencia experimental la cámara de combustión LDI diseñada en CORIA para el proyecto KIAI. El éxito en la consecución de esta tarea depende de la capacidad del código CFD de resolver las escalas espaciales y temporales implícitas al problema, y por tanto predecir correctamente la intensidad de la zona de recirculación encargada de garantizar la estabilidad de la llama formada en este enfoque LDI.The present Master's Thesis deals with the numerical resolution by means of CFD codes of a pioneering injection/combustion strategy, known as Lean Direct Injection, applied to continuous flow engines. This new concept arises as a reaction to the more stringent atmospheric pollutant emissions control, especially NOx, imposed by the relevant agencies (Committee on Aviation Environmental Protection, CAEP). The study of fuel injection, atomization and later interaction with air by means of a numerical approach is deemed to predict the detailed behavior of these phenomena affecting the overall engine cycle efficiency and emissions. This document aims to establish a solid base prior to that study, by means of the resolution of a non-reactive premixed flow that allows to characterize the structure of the turbulent velocity field formed by the air in which the fuel will be injected later. For this, the LDI combustion chamber designed in CORIA for the KIAI project is used as an experimental reference. The success in achieving this task depends on the ability of the CFD code to provide many information on temporally and spatially highly resolved scales, and therefore correctly predict the intensity of the recirculation zone responsible for guaranteeing the stability of the flame formed in this LDI approach.Belmar Gil, M. (2018). Estudio computacional del flujo no reactivo en cámaras de combustión. http://hdl.handle.net/10251/110668TFG