Este trabalho tem como eixo principal a avaliação experimental de texturas para superfícies de pás com intuito de aumentar a eficiência de ventoinhas de pequeno porte em relação às ventoinhas padrão (com pás lisas), através das variáveis também investigar de forma qualitativa o potencial de diferentes topologias no efeito estético. A ênfase está na modelagem de texturas para a superfície das pás de cada ventoinha, que foram trabalhadas a fim de diminuir a quantidade de escoamento de ar necessária para o funcionamento da mesma. Para os testes feitos, foi escolhida como base a ventoinha de um Cooler, utilizada geralmente para arrefecimento do processador de computadores, que devido à pequena escala proporciona facilidade de manuseio. A análise aconteceu através dos resultados que cada superfície projetada apresentou no túnel aerodinâmico, assim permitindo avaliar a eficiência em relação à superfície lisa. Os parâmetros como a velocidade do escoamento de ar, velocidade do corpo de prova e as relações entre essas velocidades foram definidas por um método específico para este trabalho. Espera-se como resultado que o uso das texturas com a distribuição de massa adequada consiga reduzira necessidade de escoamento de ar para o funcionamento do produto, tornando o processo de rotação mais eficiente e estético. / This work has as main shaft creating textures for surfaces of blades in order to increase the efficiency of small fans over its variables. The emphasis is on modeling the surface texture of the blades of each fan to be worked in order to reduce the need to wind to start the start of movement thereof. For testing efficiency it was chosen as the basis of a cooler fan, commonly used for cooling computers, which due to the small scale provides an ease of handling. The analysis of the results that happen through each projected surface present in the wind tunnel, thus allowing to evaluate the efficiency of using these fans in different scales and in different types of blades. The parameters such as wind speed, speed of the specimen, the relationship between these speeds and loads applied to the structure of the fan were used to set a specific method for this work. It is expected a result of the use of textures to achieve proper mass distribution annular wasting energy, making the process more efficient and aesthetic rotation.

Orientador: Kamal Abdel Radi Ismail / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-18T00:17:32Z (GMT). No. of bitstreams: 1 Matsuo_CarolinaAkemiSepulveda_M.pdf: 9560878 bytes, checksum: cc02ac79665887e2f83f47e4a06e3d8c (MD5) Previous issue date: 2011 / Resumo: Os Veículos Aéreos Não Tripulados (VANT's) possuem uma variedade de aplicações, seja monitoramento de incêndios florestais, linhas de energia, tráfego, aglomerações humanas, como também ser usado de alvo aéreo em aplicações militares. Mesmo que ainda seja um pouco restrita à aplicação civil por falta de regulamentação, tais veículos estão sendo desenvolvidos e estudados em âmbito acadêmico. A particularidade deste trabalho é o desenvolvimento de um Veículo Aéreo Não Tripulado para o uso em pulverização aeroagrícola visando reduzir os riscos de operação de vôo tripulado agrícola. Dessa maneira, é apresentada a metodologia usada para desenvolver o projeto, descrevendo o procedimento utilizado para determinar a razão peso-potência e carga alar, e as características geométricas do VANT. Os cálculos da aerodinâmica, desempenho e da estabilidade longitudinal estática do veículo são feitos analiticamente, sendo que na etapa de projeto aerodinâmico, é feita a otimização do aerofólio NACA 4415, e calculado os parâmetros aerodinâmicos do veículo completo. Além disso, por ser não tripulado, é feita a seleção do Sistema de Controle de Vôo de forma a atender os requisitos da missão. Nos cálculos do projeto são usadas as normas técnicas de homologação como a RBHA (Requisitos Brasileiros de Homologação de Aeronaves) a qual remetem às principais normas internacionais: FAR (Federal Aircraft Regulation), dos Estados Unidos da América, e a norma JAR (Joint Airworthiness Regulation). Por ser utilizado na pulverização de defensivos agrícolas é apresentada a tecnologia de aplicação dos mesmos utilizados em aeronaves tripuladas, e feito a escolha do sistema de pulverização para o veículo / Abstract: The Unmanned Aerial Vehicles (UAV's) have a variety of applications, wether monitoring of forest fires, power lines, traffic, crowds, but also can be used for aerial target military applications. Even though it is still somewhat restrict to civil application because of lack of regulation, such vehicles are being developed and studied in the academic sphere. The particularity of this work is the development of an Unmanned Aerial Vehicle for use in aerial spraying to reduce the risks of manned agricultural operation. Thus, It is presented the methodology used to determine the thrust to weight ratio and wing loading, and geometric characteristics of the UAV. Analytical calculus of aerodynamic and vehicle performance are made, and in the step aerodynamic design is made the optimization of the airfoil NACA 4415 and calculated the aerodynamic parameters of the whole vehicle. Moreover, being unmanned, it is made the selection of the Flight Control System to attend mission requirements. Technical standards for approval are used to design calculations as the RBHA (Brazilian Requirements for Approval of Aircraft) wich refer to the main international standards: FAR (Federal Aviation Regulation) of United States of America, and JAR (Joint Airworthiness Regulation).Whereas is used in the spraying of pesticides, it is presented the technology of application used in manned aircraft, and the choice of the spray system for vehicle / Mestrado / Termica e Fluidos / Mestre em Engenharia Mecânica

A key stage in the design-cycle of a military aircraft is the assessment of its vulnerability to hostile threat mechanisms. Such mechanisms inflict battle-damage to the aircraft structure and systems. This experimental investigation considered the aerodynamic consequences of simulated battle-damage to a two-dimensional wing. Key assumptions and techniques were identified leading to the modelling of both gunfire and missile fragmentation damage. Wind tunnel balance measurements were undertaken, together with surface pressure measurements and flow-visualisation methods. Force and moment results indicated extensive changes in coefficient values, whilst both smoke and surface visualisation paint successfully indicated the flow mechanisms present. Using these techniques the influences of damage and experimental variables were investigated, including damage type, size, location and Reynolds Number. Studies were also made into cases of multiple gunfire holes and the influence of internal wing construction. Results indicated that damage at quarter and half-chord locations gave greater coefficient changes than those seen for either leading or trailing edge damage. This was primarily due to reductions in the upper surface pressure peak due to through-flow. Such reductions were seen to extend in both a chordwise and spanwise direction. The flow mechanism identified indicated both similarities and differences to those of flat-plate jets in crossflows. Analysis of both gunfire and missile damage data lead to the development of a set of empirical relationships, which related damage location and size to coefficient changes.

L’enjeu de cette thèse est d’améliorer la compréhension et la prédiction du phénomène de réponse forcée des aubages de turbomachines en situation de résonance. L’étude a été menée au moyen de simulations numériques U-RANS 3D et en s’appuyant sur le compresseur d’essai ERECA, dédié au phénomène de réponse forcée. Pour prédire les amplitudes de vibration des aubages excités aérodynamiquement, la méthode de prédiction la plus répandue consiste à effectuer séparément un calcul d’excitation et un calcul d’amortissement aérodynamique ; on parle alors de calcul découplé. C’est cette méthode qui a été mise en œuvre dans un premier temps. Les calculs d’excitation et d’amortissement aérodynamiques ont été comparés individuellement aux résultats d’essais. Pour cela une méthode de traitement du signal fréquence/amplitude a été développée dans le but d’extraire l’amortissement et l’excitation des résultats d’essais. Les analyses des simulations ont permis de mieux comprendre les mécanismes d’excitation et d’amortissement aérodynamique. On a ainsi pu montrer que le phénomène d’interaction rotor/stator s’apparente par son caractère discontinu à une percussion périodique. Quant au phénomène d’amortissement, il se caractérise par le bilan des contributions de chaque zone d’échange d’énergie sur la paroi de l’aubage. En outre, les amplitudes vibratoires calculées à partir de cette méthode sont très proches des valeurs d’essais. Toutefois, cette procédure de calcul requiert la mise en œuvre de 2 calculs instationnaires différents et ne permet pas à l’heure actuelle d’être utilisée dans un cycle de conception. Dans le but de simplifier et d’améliorer la qualité de prédiction des analyses de réponse forcée, la méthode du couplage dynamique a été mise en œuvre et évaluée. Avec cette méthode, l’aubage répond librement aux sollicitations engendrées par le fluide. Une fois le régime transitoire évacué, l’aubage oscille en régime permanent. Cette méthode permet donc de prédire une amplitude vibratoire à partir d’un seul calcul instationnaire. En revanche, le calcul s’avère bien plus onéreux que la méthode découplée de par l’existence du régime transitoire. Dans le but de rendre accessible cette méthode à un niveau industriel, deux méthodes d’accélération du calcul ont été mises en place. Les résultats obtenus sont très encourageants et devraient permettre de réduire drastiquement les temps de restitution des analyses de réponse forcée. A la connaissance de l’auteur, cette thèse constitue une étude inédite de comparaison entre méthode découplée et couplage dynamique, qui par ailleurs s’appuie sur des résultats d’essais dédiés exclusivement au phénomène de réponse forcée. / The purpose of this PhD thesis is to provide a better understanding of the forced response phenomena of turbomachinery bladings in resonance conditions. The study will use 3D U-RANS calculations relying on experimental results obtained on the ERECA test case, dedicated to the forced response phenomenon. In order to predict the vibrating amplitudes of aerodynamically excited bladings, the most commonly used prediction methodology consists in separated calculations for the prediction of the aerodynamic excitation and damping ; it is the decoupled method. The predictions of these two components have been compared to the experiment individually. For this, a special signal treatment analysis has been developed so as to extract the damping and excitation from the experimental amplitude/frequency signal. The analysis of the results presented hereafter has provided a better understanding of the mechanisms involved in the aerodynamic damping and excitation. The results obtained match very closely the experiment. However, this procedure requires two different unsteady calculations and is therefore hardly usable within the design process of an engine. In order to simplify and improve the quality of the forced response analysis, the time marching method has been developed and analyzed. With this method, the blade responses freely to the aerodynamic solicitations. Once the transient regime is evacuated, the blade oscillates on its permanent regime. In order to enable access to this methodology on an industrial level, several speed-up methodologies have been implemented and the results are very encouraging. To the knowledge of the author, this thesis is the first comparison between the decoupled and the time marching methods that relies on test results from an experiment dedicated to the forced response phenomenon.

Numerical simulation of noise production and propagation is a very complex problem. A methodology fitting for one particular problem can fail for another one. So there are no general guidelines on how to deal with such phenomena. In the present work, noise propagated in non-uniform mean-flow is considered. For most cases, in the propagation field, there is a rather significant region where the mean flow is not uniform, but the sound production is negligible compared to the noise emitted by the source region. In this<p>nearfield, a linear set of propagation equations may be considered (LEE). For such problems, the following simulation methodology is proposed:<p>1. Incompressible/compressible LES simulation in the source region.<p>2. Linearized Euler Equations to propagate the noise through the nonlinear mean flow.<p>3. Kirchhoff method in the farfield, if necessary.<p>This thesis deals with the second item of this system (LEE), including interfacing with the other two steps. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Class of 2015 Abstract / Objectives: To evaluate the in vitro performance of various pressurized metered dose inhaler (pMDI) formulations by cascade impaction primarily focusing on throat deposition, fine particle fraction (FPF), and mass-median aerodynamic diameter (MMADR) measurements Methods: Ten solution pMDIs were prepared with varying cosolvent species in either low (8% w/w) or high (20% w/w) concentration. The chosen cosolvents were either alcohol (ethanol, n-propanol) or acetate (methyl-, ethyl-, and butyl acetate) in chemical nature. All formulations used HFA-134a propellant and 0.3% drug. The pMDIs were tested by cascade impaction with three different inlets to determine the aerodynamic particle size distribution (APSD), throat deposition, and FPF of each formulation. Theoretical droplet evaporation time (DET), a measure of volatility, for each formulation was calculated using the MMADR. Results: Highly volatile formulations with short DET showed consistently lower throat deposition and higher FPF than their lower volatility counterparts when using volume-constrained inlets. However, FPF values were not significantly different for pMDI testing with a non-constrained inlet. The MMADR values generated with volume-constrained inlets did not show any discernible trends, but MMADR values from the non-constrained inlet correlated with DET. Conclusions: Formulations with shorter DET exhibit lower throat deposition and higher FPF, indicating potentially better inhalational performance over formulations with longer DET. There appear to be predictable trends relating both throat deposition and FPF to DET. The shift in MMADR values for volume-constrained inlets suggests that large diameter drug particles are preferentially collected in these inlets.

Le présent travail est une étude sur la modélisation des éoliennes flottantes alliant à la fois des chargements hydrodynamiques et aérodynamiques. L’approche expérimentale a tiré profit de la grande soufflerie de Luminy opérée par le MIO (Institut Océanologique de Méditerranée), unissant une soufflerie de très bonne qualité avec un bassin équipé de systèmes de génération de houle et de courant. Les dimensions de cette installation imposent un travail à échelle très réduite introduisant ainsi les interrogations sur les similitudes à respecter (Reynolds, Froude) et les complexités de maquettage. Ces travaux ont permis de développer des outils numériques avec d’un côté une approche fréquentielle basé sur un code utilisant les éléments finis développé par l’IFP au début des années 70, et de l’autre, une approche temporelle basé sur les formulations de Morison ou de Rainey permettant l’introduction de méthodes avancées de calculs des efforts aérodynamiques. / The present work focuses on the modeling of the hydrodynamic and aerodynamic loads on a floating wind turbine. The experimental approach took advantage of the wind and wave flume in Luminy operated by the MIO (Mediterranean Institute for Oceanography) comprising a wind tunnel with a very high flow quality blowing over a wave tank. The dimensions of the installation impose working at very small scales for which the similitudes (Reynolds, Froude) introduce high modeling complexities. This work allowed the development of numerical tools using one the one hand a frequency domain approach based on a finite element code developped by IFP¨in the early seventies, and in the other hand a time-domain approach based on Morison or Rainey formulation for hydrodynamic loads allowing the introduction of advanced methods for aerodynamic loads computation.

The Advisory Council of Aeronautical Research in Europe (ACARE) has set record emission reduction targets for 2020, in response to increased awareness of global warming issues and the forecast high level of growth in global air traffic. In order to meet this legislation engine designers have to consider new and unconventional designs. An intercooled aero-engine with a heat exchanger (HX) positioned between the IP and HP compressors has the potential to reduce emissions and/or reduce specific fuel consumption relative to conventional engine cycles. In such an engine a coolant delivery system is required to bleed a proportion of the bypass flow, from behind the fan outlet guide vane (FOGV), rapidly diffuse the flow (to reduce pressure loss through the HX modules) and present it to the intercooler (i.e. heat exchanger) modules for cooling. This spent cooling air is then fed back into the bypass duct. To realise the benefits of the intercooled cycle the coolant delivery system must diffuse the flow, within the geometrical constraints, with minimal pressure loss and present it to the heat exchanger modules with suitable flow characteristics over a range of operating conditions. Therefore, a predominately experimental study, complemented with CFD predictions, was undertaken to investigate the design and performance of a coolant delivery system aimed at providing high pressure recovery in a relatively short length. For this to be achieved some pre-diffusion of the flow is required upstream of the offtake (i.e. by making the offtake larger than the captured streamtube), with a controlled diffuser or hybrid diffuser arrangement located downstream of the offtake. Although targeted at an intercooled aero-engine the concept of a system that produces a high pressure recovery in a limited length is applicable to a variety of applications. Experimental data were obtained on a modified existing low speed isothermal annular test facility operating at nominally atmospheric conditions. The offtake must operate aft of the FOGV in a highly complex flow field environment. Hence, a 1½ stage axial flow compressor (IGV, rotor and modified OGV) was used to simulate the unsteady blade wakes, secondary flows, loss cores and other turbo-machinery features that can significantly influence offtake performance. Preliminary numerical (CFD) studies enabled an offtake configuration to be determined and provided understanding of the governing fluid mechanic processes. A relatively small scale, low speed test facility was designed that had the capability to evaluate aerodynamic processes in isolation (i.e. pre-diffusion, controlled diffusion, hybrid diffusion) and full system modelling to enable the complex interaction between these flow processes to be assessed. Hence an optimal system could be characterised in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. Measurements and numerical predictions are initially presented for a baseline configuration with no offtake present. This enabled the OGV near field region to be characterised and provided a datum, relative to which the effects of introducing an offtake could be assessed. The results showed that in the near field region (i.e. within one chord downstream of the FOGV) the high velocity gradients in the circumferential direction, and associated turbulent shear stresses, dominate the profile mixing and loss production. There is little mixing out of profiles in the radial direction. Furthermore, the relatively large amount of kinetic energy associated with the compressor efflux and its subsequent mixing to a more uniform profile (i.e. reduced blockage) results in a significant static pressure recovery (Cp=5.5%). With the offtake present a variety of configurations were investigated including different levels of pre-diffusion, prior to the offtake, and different offtake positions. This enabled evaluation of the upstream pressure effects and interaction with the upstream FOGV. For very compact systems of short length, such that the gap between the OGV and offtake is relatively small, the amount of pre-diffusion achievable is limited by the offtake pressure field and its impact on the upstream OGV row. This pressure field is also influenced by parameters such as the non-dimensional offtake height and splitter thickness. For systems of increased length a significant amount of flow pre-diffusion can be achieved with little performance penalty (relative to the datum configuration). Hence, the loss associated with mixing blade wakes and secondary flows in an adverse pressure gradient is relatively small. However, the pre-diffusion level is eventually limited, to approximately 1.5, by the increased distortion and pressure losses associated with the captured streamtube. Further measurements were made with various controlled diffuser and hybrid diffusers (of varying area ratio) downstream of the offtake and various levels of pre-diffusion. The flow profile that is presented to the controlled diffuser is directly influenced by the upstream pre-diffusion process. Hence, in this case the upstream-downstream interaction is relatively strong. Conversely, the downstream-upstream interaction, between the controlled diffuser and pre-diffusion process, is relatively weak and thus has little effect on the upstream flow field. The data enabled an optimal system to be characterised (pre-diffusion/controlled diffusion split) in terms of total pressure loss, static pressure recovery and flow profiles at HX inlet. A total system diffusion of 1.8 was achievable with a pre-diffusion of 1.4 and controlled diffusion of 1.25, with further increases in either the pre-diffusion level or the controlled diffuser area ratio destabilising the system. This was achieved with an absolute mass weighted total pressure loss of 11% measured from FOGV inlet to the controlled diffuser exit plane. Utilising a hybrid bled diffuser, combined with the pre-diffusion, enabled a total system diffusion of 2.24 to be achieved. The system incorporated a 6% bleed from the hybrid diffuser and a system total pressure loss of 13%. Experimental and computational results obtained in the current research have provided an understanding of the governing flow mechanisms and quantified the geometric and aerodynamic interaction of the offtake with the FOGV and between the diffusion processes. This has enabled a design methodology to be outlined that provides approximate information on system geometry and performance (in terms of optimal diffusion split and total pressure loss) for future coolant delivery systems with minimal effort. Preliminary design maps have been developed to define the magnitude of the interaction between the offtake and FOGV in terms of the offtake height, pre-diffusion level, the splitter thickness and the axial distance between the fan OGV and offtake. In this way systems of optimal diffusion split, minimum pressure loss and minimal axial length can be determined.

No description available.

Geometrical parameterisation has an important role in the aircraft design process due to its impact on the computational efficiency and accuracy in evaluating different configurations. In the early design stages, an aircraft geometrical model is normally described parametrically with a small number of design parameters which allows fast computation. However, this provides only a course approximation which is generally limited to conventional configurations, where the models have already been validated. An efficient parameterisation method is therefore required to allow rapid synthesis and analysis of novel configurations. Within this context, the main objectives of this research are: 1) Develop an economical geometrical parameterisation method which captures sufficient detail suitable for aerodynamic analysis and optimisation in early design stage, and2) Close the gap between conceptual and preliminary design stages by bringing more detailed information earlier in the design process. Research efforts were initially focused on the parameterisation of two-dimensional curves by evaluating five widely-cited methods for airfoil against five desirable properties. Several metrics have been proposed to measure these properties, based on airfoil fitting tests. The comparison suggested that the Class-Shape Functions Transformation (CST) method is most suitable and therefore was chosen as the two-dimensional curve generation method. A set of blending functions have been introduced and combined with the two-dimensional curves to generate a three-dimensional surface. These surfaces form wing or body sections which are assembled together through a proposed joining algorithm. An object-oriented structure for aircraft components has also been proposed. This allows modelling of the main aircraft surfaces which contain sufficient level of accuracy while utilising a parsimonious number of intuitive design parameters ... [cont.].