Submitted by Santos Davilene (davilenes@ufba.br) on 2017-06-01T19:53:01Z No. of bitstreams: 1 tese_andressa (3).pdf: 1107402 bytes, checksum: 2af37806adf427975c78abffa99bafc4 (MD5) / Approved for entry into archive by Vanessa Reis (vanessa.jamile@ufba.br) on 2017-06-07T11:12:05Z (GMT) No. of bitstreams: 1 tese_andressa (3).pdf: 1107402 bytes, checksum: 2af37806adf427975c78abffa99bafc4 (MD5) / Made available in DSpace on 2017-06-07T11:12:05Z (GMT). No. of bitstreams: 1 tese_andressa (3).pdf: 1107402 bytes, checksum: 2af37806adf427975c78abffa99bafc4 (MD5) / Neste trabalho obtemos uma cota superior para a taxa exponencial de grandes desvios para observáveis contínuos em semiuxos de suspensão sobre uma base unidimensional não-uniformemente expansora com singularidades não flat ou descontinuidades, onde a função teto que define a suspensão se comporta como o logaritmo da distância para o conjunto singular/descontínuo da aplicação base. Para obtermos tal cota, mostramos que a transformação da base apresenta recorrência exponencialmente lenta para o conjunto descontínuo. Os resultados são aplicados, em particular, para semiuxos que modelam sumidouros hiperbólicos singulares em variedades tridimensionais não necessariamente transitivos. Como corolários obtemos taxas de escape de subconjuntos destes sumidouros sem medida total e resultado de existência de medida física para classes de transformações do intervalo expansoras por pedaços com singularidades.

Les écoulements vrillés, qui sont largement utilisés dans les turbines à gaz, sont connus pour être sujet à des bifurcations entre différentes topologies (grandes reconfigurations de l'écoulement) qui peuvent affecter les performances et la sécurité du moteur. Ce travail se concentre sur l'étude de ces bifurcations en utilisant la Simulation aux Grandes Echelles (SGE). Cette étude montre qu'un petit changement dans les conditions dynamique du fluide, induite par les différents modèles de sous-maille utilisés, peut provoquer une transition entre deux régimes d'écoulement distincts lorsque l'écoulement tourbillonnaire est proche des conditions critiques de transition. La sensibilité de la SGE aux modèles de sous-maille est également identifiée comme le résultat d'un manque de résolution à certains endroits critiques, un problème qui est analysé en utilisant une méthode d'adaptation de maillage. L’adaptation de maillage est testée sur des cas académiques et industriels. Ici, par ajustement de la résolution du maillage sur la base des caractéristiques de l'écoulement étudié (raffinement et grossissement de la grille en maintenant constant le coût numérique), des améliorations substantielles peuvent être obtenues, en terme de prédictions de la SGE. Ce travail peut être considéré comme une des premières étapes vers la mise en place d'une procédure standard (reproductible et indépendante de l’utilisateur) de maillage pour la SGE. / Swirling flows, which are widely employed in gas turbines, are known to undergo bifurcation between different topologies (large reconfigurations of the flow field) affecting the engine performance and safety. This work focuses on the study of such bifurcations using Large-Eddy Simulation (LES). It shows that a small change in the fluid dynamics conditions, induced by the different Sub-Grid Scale (SGS) models used in the simulations, can cause a transition between two, distinct, flow states when the swirling flow is close to transition conditions. The sensitivity of LES to SGS modeling is also identified as the result of a lack of mesh resolution at some critical locations, a problem which is analyzed using mesh adaptation. Mesh adaptation is tested on canonical and industrial flows. Here, by adjusting the mesh resolution based on the characteristics of the flow examined (refining and coarsening the grid keeping constant the numerical cost), substantial improvements of the LES predictions can be obtained. This work can be considered as the first step toward the establishment of a standard (repeatable and user independent) meshing procedure for LES.

Le transport aérien est devenu un mode de déplacement primordial, et le nombre de passagers transportés chaque année est en rapide augmentation à travers le monde. La International Civil Aviation Organization estime que ce nombre est passé de 2.2 milliards en 2009 à 3.0 milliards en 2013, dû en partie à la croissance rapide de pays émergents comme la Chine. Les réglementations concernant les émissions polluantes et sonores s’adaptent et se durcissent, entraînant de nouveaux défis pour les constructeurs aéronautiques. Les chambres de combustion évoluent vers des technologies de combustion pauvre prémélangée prévaporisée pour améliorer l’efficacité et réduire la production de gaz néfastes. Malheureusement, cette technologie tend à réduire la robustesse des moteurs, en diminuant les marges de stabilité et de stabilisation de flamme. Des études récentes indiquent que cela pourrait aussi augmenter le bruit de combustion. Afin de poursuivre le design et l’optimisation des futurs moteurs, de nouvelles méthodes sont nécessaires pour décrire et comprendre les mécanismes en jeu, et d’opérer ces moteurs en toute sécurité tout en atteignant les objectifs de la réglementation. La Simulation aux Grandes Échelles (SGE) est une approche numérique de ces problèmes, qui a montré d’excellents résultats par le passé et qui est très prometteuse pour les designs futurs. La comprehension de ces systèmes énergétiquement denses, confinés et instationnaires passe par la description des interactions flamme-turbulence, de l’acoustique et des couplages multi-physiques. À mesure que la puissance de calcul augmente, la quantité de physique qui peut être modélisée croît également, tout comme la taille des domaines de calcul. Autrefois limités à la zone de fluide réactif, la zone de mélange entre l’air et le carburant a pu être incluse, puis des parois de la chambre et des contournement de flux secondaire, jusqu’à finalement les éléments en amont et en aval de la chambre de combustion. Dans cette thèse, un solveur SGE compressible nommé AVBP est utilisé pour décrire CESAM-HP, un banc d’essai académique situé au laboratoire EM2C: une chambre de combustion pressurisée, siège d’une flamme partiellement prémélangée stabilisée par un tourbillonneur, alimente une tuyère amorcée en fin de chambre. Ces calculs décrivent simultanément la chambre et la tuyère, tout en résolvant l’acoustique, ouvrant la voie à l’étude de la dynamique du système complet, et par là aux instabilités et au bruit de combustion. Cette étude montre enfin que la stabilisation de flamme est impactée par ce comportement dynamique, qui peut parfois entraîner des retours de flamme dans l’injecteur. Ce manuscrit est organisé de la manière suivante : dans une première partie, le contexte pour la chimie, le mouvement et l’acoustique dans un écoulement réactif multi-espèces est donné. L’état de l’art en matière de thermodynamique, de thermoacoustique, de bruit de combustion et de stabilisation de flamme dans les brûleurs tourbillonnaires est présenté. Des modèles simples et des cas test sont exposés pour valider la comprehension des phénomènes en jeu de manière isolée, et des confirmations numériques sont apportées. Dans une seconde partie, les détails pratiques de la mise en œuvre de tels calculs sont donnés. Enfin, la troisième partie décrit l’application de ces outils et méthodes au banc CESAM-HP. L’inclusion de la tuyère compressible dans le domaine fournit des résultats concernant trois sujets majeurs pour le brûleur: (1) la stabilité de la flamme, en lien avec les instabilités de combustion; (2) la stabilisation de la flamme, et l’apparition de retour de flamme dans l’injecteur; (3) le bruit de combustion produit par le brûleur, ainsi que l’identification de ses diverses contributions. / Air transportation is an essential part of modern business and leisure needs, and the number of passengers carried per year is rapidly increasing worldwide. The International Civil Aviation Organization estimates that this number went from 2.2 billion in 2009 to 3.0 billion in 2013, due in part to rapid growth in emerging countries such as China. Many challenges for aircraft designers arise from this increase in air traffic, such as meeting pollutant and noise emission regulations. The engines play a major part in these emissions, and combustor technology has evolved towards high-pressure Lean Prevaporized Premixed (LPP) combustion to increase efficiency and decrease pollutant emissions. Unfortunately, this technology tends to reduce engine robustness, with a decrease in flame stability and stabilization margins. Recent studies suggest that combustion noise could also be increased in these systems. New methods are needed to describe and understand the mechanisms at hand for future design and optimization in order to operate these engines safely while still achieving emission targets. Large Eddy Simulation (LES) is a numerical approach to these problems which has shown excellent results in the past and is very promising for future design. The description of unsteady phenomena in these power-dense, confined and unsteady systems is essential to describe flame-turbulence interactions, acoustics and multiphysic couplings. As computing power grows, so does the amount of physics which can be modeled. Computational domains can be increased, and have gone from including only the reacting zone, to adding the fuel-air mixing areas, the heat liners and secondary flows, and the upstream and downstream elements. In this Ph.D., a compressible LES solver named AVBP is used to describe an academic test rig operated at the EM2C laboratory named CESAM-HP, a pressurized combustion chamber containing a swirl-stabilized partially-premixed flame and ended by a choked nozzle with high-speed flow. This leads to an accurate description of the chamber outlet acoustic behavior, and offers the possibility to investigate the dynamic behavior of the full system, and the occurrence of flame-acoustic coupling leading to combustion instabilities. It also gives insight into the combustion noise mechanisms, which are known to occur both in the reacting zone and in the nozzle. As shown in this study, this behavior also has an impact on flame stabilization in this system. This manuscript is organized as follows. In a first part, the context for chemistry, motion and acoustics of reacting multi-species flow is given. State of the art theories on reacting multi-species flow thermodynamics, thermoacoustics, combustion noise and flame stabilization in swirled burners are presented. Basic toy models and test cases are derived to validate the understanding of direct and indirect combustion noise, and numerical validations are performed. In a second part, the practical details about numerical investigation of such systems are reported. Finally, the third part describes the application of these tools and methods to the CESAM-HP4 test rig. The inclusion of the compressible nozzle in the LES computation yields results concerning three major issues for the burner: (1) flame stability, related to thermoacoustic instabilities; (2) flame stabilization, and the occurrence of flame flashback into the system’s injection duct; (3) combustion noise produced by the system, and identification of its separate contributions.

La combustion d’hydrocarbures représente encore aujourd’hui une part très majoritaire de la production d’énergie mondiale, en particulier dans la propulsion aérospatiale. La plupart des brûleurs industriels sont alimentés par un carburant sous forme liquide, qui est injecté directement dans la chambre de combustion, ce qui génère une forte interaction entre le spray, l’écoulement turbulent et la zone de combustion. Cette interaction a déjà largement été étudiée, mais certaines questions restent ouvertes. En particulier, la prise en compte de la combustion de goutte isolée dans le cadre de la Simulation aux Grandes Echelles (‘Large Eddy Simulation’ LES) de géométries complexes reste un problème difficile. L’objectif de cette thèse est d’améliorer la modélisation de la combustion du spray dans le contexte de la LES de configurations complexes avec une approche Euler-Lagrange. Dans un premier temps, un modèle de combustion de gouttes incluant les différents régimes pour la LES, appelé MustARD pour « Multi-State Algorithm for Reacting Droplets », est proposé et validé dans plusieurs configurations académiques de complexité croissante. Dans un deuxième temps, MustARD est évalué sur une configuration de brûleur expérimental et comparé aux modèles classiques sans combustion de gouttes isolées. Cette étude montre que le régime de combustion de gouttes isolées n’est pas négligeable dans une telle configuration et qu’il modifie la structure de flamme. D’autre part, les comparaisons avec les résultats expérimentaux montrent que le modèle MustARD permet d’améliorer la précision des LES de sprays turbulents réactifs. / The combustion of hydrocarbons still represents the major part of the worldwide production of energy, especially for aerospace. Most industrials burners are fed with liquid fuel that is directly injected in the combustion chamber, generating a strong interaction between the spray, the turbulent flow and the combustion. This interaction has been widely studied, but is not yet fully understood. In particular, modeling individual droplet combustion, in the framework of Large Eddy Simulation (LES) of complex geometries, is a difficult issue. This work aims at improving models for spray combustion, in the context of two-phase reactive LES of complex configurations using an Euler-Lagrange approach. First, a droplet combustion model accounting for the various regimes and called MustARD for « Multi-State Algorithm for Reacting Droplets » is proposed and validated on several academic configurations of growing complexity. Second, MustARD is evaluated in the LES of a lab-scale burner and compared to classical models neglecting individual droplet combustion. Results show in particular the importance of the new model and its impact on the flame structure. Moreover, the comparison with experiments shows that MustARD contributes to improve the numerical prediction of LES of two-phase reacting flows.

Cette thèse a pour objectif de développer une modélisation robuste pour l’endommagement ductile. En raison de l’adoucissement et du niveau de déformation élevé, les principales difficultés pratiques dans la simulation de l’endommagement ductile sont la dépendance au maillage et le verrouillage volumique. Dans ce travail, on choisit tout d’abord le cadre de grandes déformations en se basant sur un formalisme logarithmique. Puis, partant de la loi de Gurson-Tvergaard-Needleman transcrite en grandes déformations, on adopte une formulation non locale à gradient d’une variable interne qui permet de contrôler la localisation du dommage et traiter ainsi la dépendance au maillage. Ensuite, le modèle non local est couplé avec des éléments finis mixtes pour limiter le verrouillage volumique relatif à l’incompressibilité plastique. On aboutit ainsi à la construction d’un cadre de modélisation de l’endommagement ductile, indépendant du maillage et exonéré du verrouillage volumique. Les propriétés mathématiques et la performance numérique du modèle sont étudiées avec attention. Enfin, après une identification des paramètres sur un acier nucléaire, on réalise des simulations sur des éprouvettes (AE, CT, SENT) et sur une tuyauterie de réelle dimension afin de les confronter à des résultats d’essais. / The major goal of this dissertation is to develop a robust model for ductile damage simulation. Because of the softening behavior and the significantly large deformation in ductile damage, two principle difficulties should be dealt with carefully: mesh-dependency and volumetric locking. In this thesis, we adopt a logarithmic finite strain framework in which the Gurson-Tvergaard-Needleman constitutive law is reformulated. Then a non-local formulation with regularization of hardening variable is applied so as to solve mesh dependency and strain localization problem. In addition, the non-local model is combined with mixed “displacement-pressure-volume variation” elements to avoid volumetric locking. Thereby we establish a mesh-independent and locking-free finite strain framework for ductile damage modelling. Attention is paid to mathematical properties and numerical performance of the model. Finally, after an identification work of a nuclear steel,we carry out simulations on normalized specimens (NT, CT, SENT) as well as an industrial tube in order to compare with experimental results.

[pt] Em consonância com a expansão do aproveitamento fotovoltaico no mundo, o presente trabalho busca fomentar o conhecimento do nascente mercado desta fonte energética no país. É feita uma avaliação da viabilidade econômico-financeira de sistemas de geração fotovoltaica distribuída para grandes clientes da concessionária Light, a partir da estimação do preço de um sistema de médio/grande porte assim como do retorno financeiro do mesmo ao ser submetido à análises de sensibilidade envolvendo múltiplos cenários. A análise considerou estimativas relacionadas às seguintes figuras de mérito: valor presente líquido, taxa interna interna de retorno e payback. Considerando a taxa de câmbio média encontrada no primeiro semestre de 2015 (3,30Real/euro/dólar), foi observada uma majoritária condição de viabilidade dentre os 12 cenários propostos, que levaram em conta várias combinações de taxas de inflação, taxas de desconto e adoção ou não de crédito para financiamento do investimento inicial. Posteriormente, aplicou-se a mesma análise de viabilidade econômico-financeira desenvolvida a um cliente real da concessionária (Edifício do Ministério da Fazenda). Foi realizada a modelagem 3D da edificação e a verificação do sombreamento decorrente dos próprios elementos construtivos da cobertura e dos edifícios relevantes em seu entorno. Após estimada a geração de energia fotovoltaica anual pode-se, por aproximação, concluir que a mesma seria capaz de prover 11,68 por cento da necessidade anual do edifício. Projetando-se a geração futura de energia para toda a vida útil do sistema, foi possível analisar financeiramente a viabilidade do projeto segundo os mesmos 12 cenários definidos anteriormente, tendo a situação de viabilidade ocorrido em 9 deles. / [en] The last years showed an exponential growth in the use of photovoltaics in the world. The worldwide installed capacity of 23 GW in 2009 reached the expressive mark of 139 GW in 2013, being the European continent the holder of the largest portion of it (59 per cent or 81 GW). The most recent estimates describe a still small market in Brazil, with only 20 MW of installed capacity (EPE, 2014a) and mostly located in remote areas not covered by the interconnected system. Nevertheless, the growth potential of the domestic market is promising, greater even than that presented by the leaders in the use of this source. Based on the inherent natural advantages that the country possesses (such as high levels of solar radiation), it s safe to say that the photovoltaic power generation can be an important driver to increase the participation of renewable sources and the security of our energy matrix. In fact, this movement was already anticipated by planners of the electric sector. The Power Expansion Plan with 2024 horizon, prepared by the Energy Research Company (EPE), was published in december 2015 (EPE, 2015b). Among the main projections of the plan is the increase of the installed capacity of power generation in 73.000 MW. Half of this expansion is based on renewable sources (wind, solar, biomass and small hydropower plants), and 7.000 MW exclusively from photovoltaic generation. In this context, this dissertation seeks to contribute to the deepening of the studies devoted to the nascent national photovoltaic market, covering in particular the Estate of Rio de Janeiro. The objective is to evaluate the economic feasibility of photovoltaic distributed generation systems for large customers of the distribution utility Light, estimating not only the price of a photovoltaic system of medium/large size but also the financial return and sensitivity analysis contemplating multiple scenarios.

L'air que nous respirons au travers des voies aériennes supérieures est essentiel pour la vie et pour la communication orale. Dans les études de production de parole humaine, l'écoulement d'air est en général extrêmement simplifié. Or cet écoulement est complexe car turbulent et fortement sensible aux conditions limites. Dans le cas de la production de fricatives non voisées, une description plus fine de l'écoulement s'avère nécessaire pour pouvoir modéliser correctement les mécanismes aéroacoustiques sous-jacents. A l'aide d'expériences in-vitro et de simulations numériques, l'objectif de cette thèse est de contribuer à la modélisation et la caractérisation aéroacoustique d'écoulements dans des configurations de type canal avec obstacle(s), avec application à la production de fricatives non voisées. Une attention toute particulière est portée à l'influence des conditions limites et à la turbulence. / Airflow through the human upper airways is essential for life and for oral communication. In studies dealing with human speech production, airflow is mostly severely simplified. Nevertheless, this airflow is complex owing to turbulence and extreme sensitivity to boundary conditions. Recently, deeper attention has been given to characterize the airflow in the case of unvoiced fricative production and the necessity of obtaining a more detailed flow description has been outlined. With the aid of in-vitro experiments and numerical simulations, the aim of the current PhD research is to contribute to the aeroacoustic modeling and characterization of airflows through various configurations of ducts with obstacle(s), relevant for unvoiced fricative speech production. Special interest is given to the influence of boundary conditions and to turbulence.

Made available in DSpace on 2014-06-11T19:23:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T19:28:54Z : No. of bitstreams: 1 potascheff_cm_me_rcla.pdf: 651964 bytes, checksum: 79461ec2253d037c431fc957d54d050d (MD5) / Eschweilera nana é a única Lecythidoideae (Lecythidaceae) com ampla distribuição no Cerrado. A evolução floral dessa subfamília ocorreu principalmente no androceu, provavelmente em resposta aos polinizadores. Foram estudadas a atividade floral e a biologia reprodutiva da espécie e o comportamento dos seus visitantes florais. Não existe relação específica com nenhum táxon polinizador. Seu sistema de polinização envolve uma guilda de polinizadores, formada por abelhas, uma vespa e um besouro, apesar do capuz estaminal restringir o acesso ao néctar. / Eschweilera nana is the only wide spread Lecythidoideae (Lecythidaceae) native to the Brazilian Cerrado. Floral evolution of this subfamily has occurred mostly in the androecium, probably in response to selective pressures by pollinators. Floral biology and the reproductive biology of this species and the behavior of the floral visitors were studied. There is no one-toone relashionship. The pollination system of E. nana involves a guild of pollinators of mostly bees, one wasp and one beetle, despite the difficulty to access the nectar.

Este estudo objetiva a sistematização do conhecimento, através de uma abordagem multidisciplinar, de forma a conformar uma proposta inicial de protocolo de gestão ocupacional e ambiental em grandes túneis urbanos em âmbito nacional. Há na presente pesquisa uma atenção particular aos túneis urbanos dedicados ao tráfego de veículos automotores, devido às suas características físico-espaciais que os tornam especialmente perigosos e tóxicos aos seus usuários e aos funcionários envolvidos. A relativa carência de material bibliográfico de caráter sistêmico e específico no Brasil enseja à busca por referências em documentos desenvolvidos em outros países. Ainda que em nível preliminar, a compilação crítica de dados, normas e referências pesquisadas, à luz do contexto e dos instrumentos normativos brasileiros referentes ao tema, traduz-se no aspecto original desta proposta dissertativa, a ser possivelmente utilizada como ponto de partida para estudos mais extensos. São abordadas as seguintes disciplinas relativas ao objeto de pesquisa: a) Características físico-espaciais; b) Formas de uso; c) Sistema de ventilação e exaustão; d) Sistema de iluminação; e) Sistema de segurança contra sinistros e incêndio; f) Sistema de fiscalização e orientação de tráfego, comunicação e sinalização; g) Sistema de drenagem; h) Sistema de gerenciamento de resíduos sólidos. O túnel Rebouças (1962-1965) e o túnel Engenheiro Raymundo de Paula Soares (Linha Amarela) (1997), distanciados por mais de três décadas, foram escolhidos como estudos de caso, não tão somente devido aos seus portes, fluxos intensos de veículos etc., mas também devido aos contextos das evoluções normativas em que se inserem. / Aiming to establish an initial proposal for an environmental and operational management protocol for large urban tunnels, one that could be applied nationwide, this study also intends to systematize, through a multidisciplinary approach, the state of the art on the subject. In this survey it will be given particular attention to vehicular urban tunnels. Due to its physical and spatial characteristics they are especially dangerous and toxic to both their users and employees involved in maintenance. Given the lack of systematic and specific bibliographic material in Brazil it was necessary to inquire about references, studies and investigations developed in other countries. A critical compilation of such data, standards and benchmarks, while in its initial level, considering the Brazilian context and the actual legal instruments, may reflect the original feature of this essay. It is hoped that the results can be used as a starting point for other extensive studies. Considering the main focus of this research, the following topics are discussed: a) physical and spatial characteristics; b) usage and operation; c) ventilation and exhaust system; d) lighting system; e) accidents prevention, security and fire protection system; f) management, traffic supervision, communication and signaling system; g) drainage system; h) solid waste management system. The two tunnels, Rebouças (1962-1965) and Engenheiro Raymundo de Paula Soares (Linha Amarela) (1997), both located in Rio de Janeiro and more than three decades apart, were selected as case studies, not only Because of their size, intensity of flows etc., but also because of the changing normative contexts in which they operate.

A técnica cirúrgica endoscópica transluminal por orifícios naturais (NOTES) envolve o acesso à cavidade abdominal através de uma perfuração intencional de uma víscera (p.ex. estômago, reto, vagina, bexiga urinária) com um endoscópio flexível para acessar a cavidade abdominal e realizar uma exploração intra-abdominal. O presente estudo teve por objetivo verificar a viabilidade de se realizar a técnica cirúrgica endoscópica transvaginal híbrida em éguas para a exploração da cavidade abdominal posicionados em estação e distribuídos em dois grupos conforme o acesso laparosópico pelo flanco direito ou esquerdo e pela incisão do saco fundo vaginal à esquerda da cérvix na posição horária de 9 horas ou à direita da cérvix na posição horária de 3 horas. O abdômen foi explorado sob visualização endoscópica utilizando um endoscópio flexível de 2 metros por 14 mm de diâmetro. A incisão vaginal foi realizada sob visualização indireta pelo laparoscópio acessado via flanco. Foram utilizados 6 éguas hígidas e 1 égua com histórico de lesão abdominal por arma de fogo. Os animais foram submetidos a jejum alimentar de 24 a 36 horas, distribuídos em dois grupos. No grupo 1 foram incluídos animais que foram acessado o flanco esquerdo para a introdução do laparoscópico e realizado a incisão do saco vaginal à esquerda da cérvix, enquanto no grupo 2, o acesso do flanco para a introdução abdominal do laparoscópio foi pelo lado direito e a incisão vaginal à direita da cérvix. Os animais foram sedados com a combinação de cloridrato de xilazina e butorfanol e para dessensibilização cutânea e muscular realizada no flanco esquerdo e direito e a execução da epidural baixa foi utilizada lidocaína. A técnica cirurgia realizada foi a cirurgia endoscópica transluminal híbrida pelo acesso vaginal utilizando uma cânula vaginal que permitiu a introdução do endoscópio flexível e facilitando a passagem para o lado contralateral da incisão vaginal do endoscópio flexível para realizar a visualização da cavidade abdominal. Foi possível visualizar em todos os animais o diafragma, o estômago, o lobo hepático esquerdo, direito e processo caudato, o baço, projeções do rim esquerdo e direito, o cólon menor, o ovário esquerdo e direito, o ligamento largo do útero, o corno uterino e as tubas uterinas esquerda e direita, o duodeno, a base do ceco, o cólon dorsal direito e as alças do intestino delgado. Não foi identificadoo forame epiplóico, o pâncreas, o reto e a bexiga em nenhum dos animais do estudo. O procedimento endoscópico transvaginal híbrido para a exploração da cavidade abdominal em éguas hígidas não evidenciou dificuldade em sua execução nem complicações pós-cirúrgicas, sendo viável nos dois diferentes grupos propostos, como também auxiliou no diagnóstico de lesões intra-abdominais em uma égua causadas por arma The natural orifice translumenal endoscopic surgery (NOTES) technique involves the access to the abdominal cavity through an intentional perforation of a viscus (i.e. stomach, rectus, vagina, urinary bladder) with an endoscope in order to access the abdominal cavity and perform an intra-abdominal exploration. Until now, abdominal surgery in horses using minimally invasive techniques has been performed through laparoscopy. The objective of this study was to confirm the availability to perform the hybrid transvaginal endoscopic surgery technique in mares in order to explore the abdominal cavity in the standing position. The mares were divided in two groups according to the laparoscopic access through the left or right flank. / The natural orifice translumenal endoscopic surgery (NOTES) technique involves the access to the abdominal cavity through an intentional perforation of a viscus (i.e. stomach, rectus, vagina, urinary bladder) with an endoscope in order to access the abdominal cavity and perform an intra-abdominal exploration. Until now, abdominal surgery in horses using minimally invasive techniques has been performed through laparoscopy. The objective of this study was to confirm the availability to perform the hybrid transvaginal endoscopic surgery technique in mares in order to explore the abdominal cavity in the standing position. The mares were divided in two groups according to the laparoscopic access through the left or right flank. An incision was performed on the posterior vaginal fornix on the left side of the cervix in a 9 o’clock position or on the right side of the cervix on a 3 o’clock position. The abdomen was explored under endoscopic visualization using a 2 meters long flexible endoscope by 14 mm in diameter. The vaginal incision accessed via flank was performed under indirect visualization using a laparoscope. Six healthy mares and one mare with the history of abdominal lesion by gun fire were used. The horses were subjected to fasting from 24 to 36 hours and they were divided in two groups according to the laparoscopic access through the flank and vaginal incision. In group 1, horses were accessed on the left flank to the introduction of the laparoscope and it was performed an incision on the vaginal fornix in the left side of the cervix. In group 2, the access of the flank to the abdominal introduction of the laparoscope was through the left side and the vaginal incision in the left side of the cervix. The horses were sedated using a combination of xylazine chloride and butorphanol. Lidocaine was used for skin and muscular anesthesia on the left and right flank and for the execution of low epidural. The surgery technique used was the hybrid NOTES through the vaginal access using a vaginal cannula which allowed the introduction of the flexible endoscope making it rigid and the passage of the endoscope to the contralateral side of the vaginal incision to visualize the abdominal cavity. In all the animals of the experiment, it was possible to see the diaphragm, stomach, left, right and caudate liver lobe, spleen, left and right kidney projection, small colon, left and right ovaries, broad ligament of the uterus, uterine horn and right and left uterine tubes, duodenum, base of the cecum, left dorsal colon, and bowel loops of the small intestine. There were not identified foramen epiploicum, pancreas, rectus, and bladder in none of the animals in the experiment. The hybrid transvaginal endoscopic procedure for the exploration of the abdominal cavity in healthy mares did not demonstrate difficulties in its execution not even post-surgery complications. The procedure was considered viable in both different proposed groups.