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Controle Actif Des Instabilites De Combustion Dans Les Turbines A Gaz Bas Nox
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Book Synopsis Contrôle actif des instabilités de combustion dans les turbines à gaz bas-NOx by : Daniel Bernier
Download or read book Contrôle actif des instabilités de combustion dans les turbines à gaz bas-NOx written by Daniel Bernier and published by . This book was released on 2001 with total page 263 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les instabilités de combustion apparaissent souvent dans les turbines à gaz et engendrent des dommages importants. Le travail mené ici consiste en l'étude du contrôle actif de ces instabilités sur un foyer prémélangé prévaporisé. Une telle étude constitue une étape de base pour l'application du contrôle actif dans les turbines à gaz. Après une analyse détaillée des mécanismes impliqués dans les instabilités de combustion, différents systèmes actionneurs modulant une partie du débit d'air sont testés pour leur application au contrôle actif. Le système le plus efficace agit à la base du brouillard de combustible et permet un contrôle des instabilités en configuration co-rotative des vrilles de l'injecteur. Par contre, le système perd en efficacité à des fréquences supérieures a 300 Hz en configuration contra-rotative. L'actionneur est ensuite utilisé pour évaluer quatre stratégies de contrôle. On considère d'abord une boucle ouverte (injection de bruit blanc) et une boucle fermée élémentaire (ligne à retard). On envisage ensuite deux contrôleurs adaptatifs. Le premier nécessite une identification préalable du comportement du système. Le second réalise cette identification simultanément au contrôle. Dans le foyer étudié, le contrôle en boucle ouverte permet une réduction supérieure à 60% du niveau d'instabilité sans risque de divergence du processus. Les plus fortes réductions sont obtenues avec l'algorithme auto-adaptatif et atteignent 70% du niveau d'instabilité. Dans l'ensemble des stratégies de contrôle, la réduction des instabilités est obtenue avec une modulation de 3% du débit d'air global. Les performances du contrôleur sont principalement limitées par le niveau de modulation obtenu avec l'actionneur et sa bande-passante. La synthèse des stratégies de contrôle permet une discussion sur leur complexité technologique au regard d'une application industrielle.
Book Synopsis Contrôle actif des instabilités de combustion dans les turbines à gaz by : Nicolas Robart
Download or read book Contrôle actif des instabilités de combustion dans les turbines à gaz written by Nicolas Robart and published by . This book was released on 2000 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les instabilités de combustion sont des phénomènes néfastes dans les turbines à gaz. Elles sont la conséquence d'un couplage entre la réaction chimique et l'acoustique de la chambre de combustion. Une voie pour lutter contre ces instabilités est le contrôle actif de la combustion. La spécificité de ce travail vient de la complexité de l'écoulement diphasique étudié. Cet écoulement est produit par un injecteur de turboréacteur de géométrie industrielle qui forme un jet d'air vrillé axisymétrique au centre duquel sont injectées des gouttelettes de carburant. La principale tâche consiste à développer et tester des actionneurs agissant sur le mélange. Les actionneurs utilisés sont basés sur 4 petits jets d'air à haute vitesse et ont été choisis suite à une étude complète des techniques existantes. Des mesures de granulométrie, de vitesse d'air et des visualisations de répartition spatiale des gouttes ont montré l'influence des actionneurs sur le spray. Parmi les actionneurs développés, certains ont été capable de diminuer la taille des gouttes, de modifier la répartition spatiale des gouttes, et de modifier le champ aérodynamique dans l'injecteur. Ces actionneurs ont été associés à une vanne haute fréquence permettant de pulser l'air jusqu'à plus de 400 Hz. Les actionneurs les plus efficaces sur le mélange ont été testés sur un banc expérimental avec combustion. Ils ont permis d'exciter la flamme à des fréquences de l'ordre des fréquences naturellement instables (de 350 à 450 Hz) du brûleur, ce qui laisse envisager la faisabilité du contrôle en boucle fermée à ces fréquences. Une autre voie a été explorée, elle consiste à alimenter les actionneurs en continu et observer si les effets sur le mélange suffisent à modifier la stabilité de la flamme. Cette voie a permis de lutter à certains régimes contre les instabilités, et plus systématiquement contre le "flashback". Améliorer ces résultats nécessite d'utiliser des stratégies de contrôle en boucle fermée.
Book Synopsis Active Control of Combustion Instabilities in Low Nox Gas Turbines by : Ben T. Zinn
Download or read book Active Control of Combustion Instabilities in Low Nox Gas Turbines written by Ben T. Zinn and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Combination of Active Instability Control and Passive Measures to Prevent Combustion Instabilities in a 260MW Heavy Duty Gas Turbine by : J. Hermann
Download or read book Combination of Active Instability Control and Passive Measures to Prevent Combustion Instabilities in a 260MW Heavy Duty Gas Turbine written by J. Hermann and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reducing the output of NOx pollutants and enhancing efficiency are the two major aims pursued by developers of modern gas turbines. In order to achieve them. lean premix combustion is preferred turbine inlet temperatures and thus power densities within the combustion chamber system being continuously increased to augment efficiency. Due to this fact. the tendency of modern combustion systems to develop so-called self- excited combustion oscillations keeps increasing. After briefly discussing the oscillation problems encountered with the annular combustion chamber of a Siemens type V94.3A stationary gas turbine. particular attention will be paid to suppressing these oscillations by passive and active means. The passive measures presented. i.e. extending the burner nozzle were intended to detune the combustion system by prolonging the time lag required by the combustible mixture exiting the burner outlet to reach the combustion zone Moreover. to suppress periodic vortex shedding. another possible cause for combustion instabilities. those extensions were inclined in a certain angle with respect to the main flow direction. To prevent the in-phase lock of all 24 burners promoting the excitation of any azimuthal mode the burners were selected to have different time lags and were arranged asymmetrically within the annular combustion chamber. In addition to these passive measures, a multi-channel Active Instability Control (AIC) system was implemented to achieve further damping. With the AIC system presented. any homer oscillations occurring are measured by p-ressure sensors their signals are processed by means of a multi-channel controller and then transmitted to actuators designed to damp down combustion oscillations. The points of intervention selected to do so were the gas supplies of the pilot flames.
Book Synopsis Active Combustion Control for Aircraft Gas Turbine Engines by :
Download or read book Active Combustion Control for Aircraft Gas Turbine Engines written by and published by . This book was released on 2000 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions. Part I: Physics-Based and Experimentally Identified Models of Combustion Instability by : C. A. Jacobson
Download or read book Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions. Part I: Physics-Based and Experimentally Identified Models of Combustion Instability written by C. A. Jacobson and published by . This book was released on 2000 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper details the development of a thermoacoustic model and associated dynamic analysis. The model describes the results obtained in a gas fueled experimental combustion program carried out at UTRC. The contents of the paper are (a) the development of a thermoacoustic model composed of acoustic and heat release components, (b) the dynamic analysis of the resulting non-linear model using harmonic balance methods to compute linear stability boundaries and the amplitudes of oscillations and (c) the calibration of the model to experimental data.
Book Synopsis Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions. Part II: Adaptive Control Algorithm Development, Demonstration and Performance Limitations by : Andrzej Banaszuk
Download or read book Active Control of Combustion Instabilities in Gas Turbine Engines for Low Emissions. Part II: Adaptive Control Algorithm Development, Demonstration and Performance Limitations written by Andrzej Banaszuk and published by . This book was released on 2001 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present results of experiment with two distinct extremum-seeking adaptive algorithms for control of combustion instability suitable for reduction of acoustic pressure oscillations in gas turbine over large range of operating conditions. The algorithms consists of a frequency tracking Extended Kalman Filter to determine the in-phase component, the quadrature component, and the magnitude of the acoustic mode of interest, and a phase shifting controller with the controller phase tuned using an extremum-seeking algorithms. The algorithms are also applicable for control of oscillations of systems whose oscillation frequency and optimal control phase shift depends on operating conditions, and which are driven by strong broad-band disturbance. The algorithms have been tested in combustion experiments involving full-scale engine hardware and during simulated fast engine transients.
Book Synopsis Causes of Combustion Instabilities with Passive and Active Methods of Control for Practical Application to Gas Turbine Engines by : Michael D. Cornwell
Download or read book Causes of Combustion Instabilities with Passive and Active Methods of Control for Practical Application to Gas Turbine Engines written by Michael D. Cornwell and published by . This book was released on 2011 with total page 415 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion at high pressure in applications such as rocket engines and gas turbine engines commonly experience destructive combustion instabilities. These instabilities results from interactions between combustion heat release, fluid mechanics and acoustics. This research explores the significant affect of unstable fluid mechanics processes in augmenting unstable periodic combustion heat release. The frequency of the unstable heat release may shift to match one of the combustors natural acoustic frequencies which then can result in significant energy exchange from chemical to acoustic energy resulting in thermoacoustic instability. The mechanisms of the fluid mechanics in coupling combustion to acoustics are very broad with many varying mechanisms explained in detail in the first chapter. Significant effort is made in understanding these mechanisms in this research in order to find commonalities, useful for mitigating multiple instability mechanisms. The complexity of combustion instabilities makes mitigation of combustion instabilities very difficult as few mitigation methods have historically proven to be very effective for broad ranges of combustion instabilities. This research identifies turbulence intensity near the forward stagnation point and movement of the forward stagnation point as a common link in what would otherwise appear to be very different instabilities. The most common method of stabilization of both premixed and diffusion flame combustion is through the introduction of swirl. Reverse flow along the centerline is introduced to transport heat and chemically active combustion products back upstream to sustain combustion. This research develops methods to suppress the movement of the forward stagnation point without suppressing the development of the vortex breakdown process which is critical to the transport of heat and reactive species necessary for flame stabilization. These methods are useful in suppressing the local turbulence at the forward stagnation point, limiting dissipation of heat and reactive species significantly improving stability. Combustion hardware is developed and tested to demonstrate the stability principles developed as part of this research. In order to more completely understand combustion instability a very unique method of combustion was researched where there are no discrete points of combustion initiation such as the forward stagnation point typical in many combustion systems including swirl and jet wake stabilized combustion. This class of combustion which has empirical evidence of great stability and efficient combustion with low CO, NOx and UHC emissions is described as high oxidization temperature distributed combustion. This mechanism of combustion is shown to be stable largely because there are no stagnations points susceptible to fluid mechanic perturbations. The final topic of research is active combustion control by fuel modulation. This may be the only practical method of controlling most instabilities with a single technique. As there are many papers reporting active combustion control algorithms this research focused on the complexities of the physics of fuel modulation at frequencies up to 1000 Hz with proportionally controlled flow amplitude. This research into the physics of high speed fluid movement, oscillation mechanical mechanisms and electromagnetics are demonstrated by development and testing of a High Speed Latching Oscillator Valve.
Book Synopsis Active Control of Combustion Instabilities in GE's Gas Turbines by : Benjamin Zinn
Download or read book Active Control of Combustion Instabilities in GE's Gas Turbines written by Benjamin Zinn and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Application of Active Combustion Instability Control to a Heavy Duty Gas Turbine by : J. R. Seume
Download or read book Application of Active Combustion Instability Control to a Heavy Duty Gas Turbine written by J. R. Seume and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the ASME ASIA '97 Congress & Exhibition, Singapore, Sep 30-Oct 2, 1997.
Book Synopsis Étude théorique et expérimentale d'un système de contrôle actif adaptatif des instabilités de combustion by : Can Huynh Huu
Download or read book Étude théorique et expérimentale d'un système de contrôle actif adaptatif des instabilités de combustion written by Can Huynh Huu and published by . This book was released on 1993 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les instabilités de combustion apparaissent dans de nombreux systèmes de combustion industriels. Une étude expérimentale de ce phénomène a été réalisée. Les résultats obtenus avec un système d'imagerie a moyenne de phase, couple a des moyens d'investigation classiques mettent en évidence les interactions entre l'acoustique du système, la distribution du taux de dégagement de chaleur et la dynamique des jets de réactifs. Dans une deuxième partie, un système de contrôle actif adaptatif a été développé. Ce système est base sur une régulation en boucle fermée. Une détermination automatique des paramètres du contrôleur est possible. De plus, celui-ci est en mesure de suivre les évolutions du point de fonctionnement de la chambre de combustion. La dernière partie présente une modélisation théorique et numérique du phénomène d'instabilité de combustion et de son contrôle. Le modèle permet de simuler numériquement les divers algorithmes de contrôle avant leur implémentation expérimentale. Il est également utilise pour prévoir l'influence des divers paramètres du contrôle sur les performances du système de régulation
Book Synopsis Advanced Combustion and Aerothermal Technologies by : Nick Syred
Download or read book Advanced Combustion and Aerothermal Technologies written by Nick Syred and published by Springer. This book was released on 2007-10-16 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here readers will find a summary of proceedings at a highly important NATO workshop. The ARW Advanced Combustion and Aerothermal Technologies: Environmental Protection and Pollution Reductions, was held in Kiev, May 2006. The workshop was co-directed by Profs. N. Syred and A.Khalatov, winners of the NATO Scientific Prize 2002, and was organized by the Institute of Thermophysics (Ukraine) and Cardiff University, UK. The primary workshop objective was to assess the existing knowledge on advanced combustion and aerothermal technologies providing reduced environmental impact.
Book Synopsis Gas Turbine Theory by : G.F.C. Rogers
Download or read book Gas Turbine Theory written by G.F.C. Rogers and published by Pearson Higher Ed. This book was released on 2017-06-07 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: When the First Edition of this book was written in 1951, the gas turbine was just becoming established as a powerplant for military aircraft. It took another decade before the gas turbine was introduced to civil aircraft, and this market developed so rapidly that the passenger liner was rendered obsolete. Other markets like naval propulsion, pipeline compression and electrical power applications grew steadily. In recent years the gas turbine, in combination with the steam turbine, has played an ever-increasing role in power generation. Despite the rapid advances in both output and efficiency, the basic theory of the gas turbine has remained unchanged. The layout of this new edition is broadly similar to the original, but greatly expanded and updated, comprising an outline of the basic theory, aerodynamic design of individual components, and the prediction of off-design performance. The addition of a chapter devoted to the mechanical design of gas turbines greatly enhances the scope of the book. Descriptions of engine developments and current markets make this book useful to both students and practising engineers.
Book Synopsis Solid Propellant Rocket Research by : Martin Summerfield
Download or read book Solid Propellant Rocket Research written by Martin Summerfield and published by Elsevier. This book was released on 2013-11-11 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid Propellant Rocket Research
Download or read book ECO-COMPASS written by Xiaosu Yi and published by MDPI. This book was released on 2019-04-25 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Today, mainly man-made materials, such as carbon and glass fibers, are used to produce composite parts in aviation. Renewable materials, such as natural fibers or bio-sourced resin systems, have not yet found their way into aviation. The project ECO-COMPASS aims to evaluate the potential applications of ecologically improved composite materials in the aviation sector in an international collaboration of Chinese and European partners. Natural fibers such as flax and ramie will be used for different types of reinforcements and sandwich cores. Furthermore, bio-based epoxy resins to substitute bisphenol-A based epoxy resins in secondary structures are under investigation. Adapted material protection technologies to reduce environmental influence and to improve fire resistance are needed to fulfil the demanding safety requirements in aviation. Modelling and simulation of chosen eco-composites aims for an optimized use of materials while a Life Cycle Assessment aims to prove the ecological advantages compared to synthetic state-of-the-art materials. This Special Issue provides selected papers from the project consortium partners.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Edith and Florence Stoney, Sisters in Radiology by : Adrian Thomas
Download or read book Edith and Florence Stoney, Sisters in Radiology written by Adrian Thomas and published by Springer. This book was released on 2019-07-01 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores the lives and achievements of two Irish sisters, Edith and Florence Stoney, who pioneered the use of new electromedical technologies, especially X-rays but also ultraviolet radiation and diathermy. In addition, the narrative follows several intertwined themes as experienced by the sisters during their lifetimes. Their upbringing, influenced by their liberal-minded scientist father, set the tone for both their lives. Irish independence fractured their family heritage. Their professional experiences, fulfilling for Florence as a qualified doctor but often frustrating for Edith as a Cambridge-educated scientist, mirrored those of other aspiring women during this period, when the suffragist movement expanded and women’s lobby groups were formed. World War I created an environment in which their unusual specialist knowledge was widely needed, and the sisters’ war experiences are carefully examined in the book. But ultimately this is the extraordinary story of two independent but closely bonded sisters and their abiding love and support for one another.
