In this research, the impact of solar thermal water heaters on the electric water heating load curve in a residential distribution circuit is analyzed with realistic hot water draw profiles. For this purpose, the electric and solar thermal water heater models are developed in MATLAB and validated with results from GridLAB-D and TRNSYS respectively. The solar thermal water heater model is developed for two types of collectors namely the flat plate and evacuated glass tube collector. Simulations are performed with the climate data from two cities - Madison, WI and Tampa, FL - which belong to two very different climate zones in the United States. Minute-by-minute electric energy consumptions in all three configurations of water heaters are modeled for a single water heater as well as a residential distribution circuit with 100 water heaters for daily as well as monthly time frames. The research findings include: The electric energy saving potential of a solar thermal water heater powered by auxiliary electric element is in the range of 40-80% as compared to an all-electric water heater depending on the site conditions such as ambient temperature, sunshine and wind speed. The simulation results indicate that the energy saving potential of a solar thermal water heater is in the range of 40-70% during winter and 60-80% during summer. Solar thermal water heaters aid in reducing the peak demand for electric water heating in a distribution feeder during sunshine hours when ambient temperatures are higher. The simulation results indicate that the peak reduction potential of solar thermal water heaters in a residential distribution feeder is in the range of 25-40% during winter and 40-60% during summer. The evacuated glass tube collectors save an additional 7-10% electric energy compared to the flat plate collectors with one glass pane during winter and around 10-15% during summer. The additional savings result from the capability of glass tube collectors to absorb ground reflected radiation and diffuse as well as direct beam radiation for a wider range of incidence angles. Also, the evacuated glass tube structure helps in reducing wind convective losses. From the simulations performed for Madison, WI and Tampa, FL, it is observed that Tampa, FL experiences more energy savings in winter than Madison, WI, while the energy savings are almost the same in summer. This is due to the fact that Tampa, FL has warmer winters with higher ambient temperatures and longer sunshine hours during the day compared to Madison, WI while the summer temperatures and sunshine hours are almost the same for the two cities. As expected, the simulation results prove the fact that lowering the hot water temperature set point will result in the reduction of electricity consumption. For a temperature reduction from 120 deg. F to 110 deg. F, electric water heaters save about 25-35% electric energy whereas solar thermal water heaters save about 30-40% auxiliary electric energy for the same temperature reduction. For the flat plate collectors, glass panes play an important role in auxiliary electric energy consumption. Flat plate collectors with two glass panes save about 10-15% auxiliary electric energy compared to those with no glass panes and about 3-5% energy saving compared to collectors with one glass pane. This is because there are reduced wind convective losses with glass panes. However, there are also transmittance losses from glass panes and there are upper limits on how many glass panes can be used. Results and findings from this research provide valuable insight into the benefits of solar thermal water heaters in a residential distribution feeder, which include the energy savings and peak demand reduction. / Master of Science

Heat transfer augmentation is of paramount importance in energy transfer and storage systems and the idea of using the inherent vibrations in a system to enhance heat transfer needs to be thoroughly researched upon. The current study numerically investigates an infinitesimally thin plate-fin undergoing forced oscillations over a range of amplitudes and frequencies in the presence of an approach flow. Reduced frequencies of 0.25 ≤ k ≤16 and plunge amplitudes of 0.03125 ≤ h ≤ 8 are investigated at Re=100 and Pr = 0.71. It is shown that the combined effect of frequency and amplitude on heat transfer enhancement can be accounted for as a single parameter “plunge velocity” (0.25 ≤ kh ≤ 4) instead of the individual frequency and amplitude values. For kh > 0.5 a significant increase in Nusselt number ( is observed compared to a stationary plate. With increasing kh or more vigorous oscillations, the increase in becomes more prominent and similar trends and comparable magnitudes were observed for a constant value. Unlike the hydrodynamic counterpart of the study, both Leading Edge Vortices (LEVs) and Trailing Edge Vortices (TEVs) are found to act positively to induce enhanced heat transfer on the plate. Finally, the dependence of heat transfer augmentation on the frequency and amplitude of vibration is quantified with a simple parameterization for a plate-fin in a fluid medium. / M.S. / Heat transfer enhancement is of paramount importance in energy transfer and storage systems. The idea of using the inherent mechanical vibrations in a heat producing system to enhance transfer of unwanted heat from that system needs to be thoroughly researched upon. To investigate this idea, we numerically study an infinitesimally thin plate-fin undergoing forced oscillations over a range of amplitudes and frequencies in the presence of an incoming air flow. It is shown that the combined effect of frequency and amplitude on heat transfer enhancement can be accounted for as a single parameter called “plunge velocity” instead of the individual frequency and amplitude values. For a significant plunge velocity, a significant increase in Nusselt number ( is observed compared to a stationary plate representing an increase in the extent of heat transferred. With more vigorous oscillations, the increase in becomes more prominent and similar trends and comparable magnitudes were observed for a constant value. Finally, the dependence of heat transfer augmentation on the frequency and amplitude of vibration is quantified with a simple parameterization for a plate-fin in a fluid medium.

Near wake is the region of wake flow just behind the trailing edge of the body where the flow is strongly influenced by the upstream flow conditions and also perhaps by the charac­teristics of the body. The present work is concerned with the study of the development of turbulent near wake behind an infinitely yawed flat plate. The turbulent near wake behind an infinitely yawed flat plate is the simplest of the three-dimensional turbulent near wake flows. The present study aims at providing a set of data on the turbulent near wake behind an infinitely yawed flat plate and also at understanding the development and structure of the near wake. Detailed measurements of mean and turbulent quantities have been made using 3-hole probe, X-wire and 3-wire hotwire probes. Further an asymptotic analysis of the two-dimensional turbulent near wake flow has been formulated for the near wake behind an infinitely yawed flat plate. The feature that the near wake which is dominated by mixing of the oncoming turbulent boundary layer retains, to a large extent, the memory of the turbulent structure of the boundary layer, has been exploited to develop this analysis. The analysis leads to three regions of the wake flow (the inner near wake, the outer near wake and the far wake) for which the governing equations are derived. The matching conditions among these regions lead to logarithmic variations in both normal and longitudinal directions in the overlapping regions surrounding the inner wake. These features are validated by the present results. A computational study involving seven well known turbulence models was also under­taken in order to assess the performance of the existing turbulence models in the prediction of the turbulent near wake behind an infinitely yawed flat plate. In this study all the seven models are implemented into a common flow solver code, thus eliminating the influence of grid size, initial conditions and different numerical schemes while making the comparison. This study shows that the K - e model performs better than other models in predicting the near wake behind an infinitely yawed flat plate.

The thesis deals with energy simulation of a solar energy system in a low-energy family house with warm-air heating. The simulations performed resulted in the assessment of the energy contribution of four solar systems with different types of collectors. The profitability and return of investment for the particular system have been evaluated based on investment costs and the savings gained. The theoretical part includes an introduction to the solar energy field, solar panel systems and the passive house concept. The practical part is devoted to description of the simulated object models as used in the TRNSYS environment, the simulation results evaluation along with the assessment of the economic return on investment. The conclusion recommendations regarding a suitable type and size of the solar panel with respect to the economic criteria chosen are given.

<p>Many flow cases in fluid dynamics face undesirable flow separation due torising static pressure on wall boundaries. This occurs e.g. due to geometry as ina highly curved turbine inlet duct or e.g. on flow control surfaces such as wingtrailing edge flaps within a certain angle of attack range. Here, flow controldevices are often used in order to enhance the flow and delay or even totallyeliminate flow separation. Flow control can e.g. be achieved by using passiveor active vortex generators (VG) that enable momentum mixing in such flows.This thesis focusses on passive VGs, represented by VG vanes that are mountedupright on the surface in wall-bounded flows. They typically have an angle ofincidence to the mean flow and, by that, generate vortex structures that in turnallow for the desired momentum mixing in order to prevent flow separation.A statistical VG model approach, developed by KTH Stockholm and FOI,the Swedish Defence Research Agency, has been evaluated computationally.Such a statistical VG model approach removes the need to build fully resolvedthree-dimensional geometries of VGs in a computational fluid dynamics mesh.Usually, the generation of these fully resolved geometries is rather costly interms of preprocessing and computations. By applying this VG model, thecosts reduce to computations without VG effects included. Nevertheless, theVG model needs to be set up in order to define the modelled VG geometry inan easy and fast preprocessing step. The presented model has shown sensitivityfor parameter variations such as the modelled VG geometry and the VG modellocation in wall-bounded zero pressure gradient and adverse pressure gradientflows on a flat plate, in a diffuser, and on an airfoil with its high-lift systemextracted. It could be proven that the VG model qualitatively describes correcttrends and tendencies for these different applications.</p>

This thesis investigates the mechanisms behind the control of a typical two line kite, where the lines are attached to the kite side by side. This arrangement gives the kite flyer the ability to apply a roll angle to the kite, which then results in a yawing motion. The reason for this yaw rotation has not been adequately described previously. The definitions of roll and yaw for a kite have been re-defined to match the real world behaviour of the kite-bridle-line system. Specifically, these are defined as rotations relative to the lines rather than the kite itself. This detail has been neglected in previous research, and has a significant effect on the turning behaviour of a kite. A static model of a kite represented by flat disks was created. This model allows the out of balance forces and moments to be found for a kite when it is held at any position. When the kite is held with a roll angle applied, the disk angles of attack become unequal. This causes a change in the magnitude, direction, and point of action of the aerodynamic forces on each disk, which can lead to a yaw moment. While this does not give a complete picture of how a kite turns, it does explain one of the two mechanisms that cause a kite to begin to yaw when a roll angle is applied. The other mechanism is due to the velocity of the roll rotation, and is out of the scope of this thesis since a dynamic analysis would be required. The static model showed that any variation to kite geometry or any parameter that affects the equilibrium position of the kite will affect turning response. The most important of these parameters for a simple kite represented by two disks is the dihedral angle. A minimum negative dihedral angle (or anhedral) is required for a kite to turn in the expected direction when a roll angle is applied. The value of the minimum anhedral angle required for this behaviour varies with other parameters, but is generally between 8° and 20°. Other parameters such as bridle geometry also affect the turning response of a kite, primarily because they alter the equilibrium positions of the kite and line. Altering these equilibrium positions has a strong effect on turning response, since it changes the initial disk angles of attack. Additionally, if the kite and line are not aligned perpendicular to each other (which is a rare condition for a kite) a roll angle further changes the disk angles of attack, since the roll angle is applied about an axis relative to the line rather than the kite. An investigation into the effect of varying wind velocity on turning response showed that it has an important effect. Some kites will reverse their response to a given roll angle at some wind velocities, which could make the kite very difficult to control. Additionally, some kites can alter their equilibrium positions sharply with wind velocity, again causing varying turning behaviour as the wind conditions change. Future work should examine the dynamic turning response of kites. A dynamic simulation could be used to examine how the turning response of a kite is influenced by the rate at which a control input is applied. Additionally, the behaviour of the kite once the initial turning movement has begun could be assessed.

Este trabalho apresenta um modelo inovador de coletor solar plano, com placa absorvedora fabricada por Estampagem Incremental e Soldagem FSW (Friction Stir Welding). Esta placa absorvedora é constituída de duas chapas de alumínio AA1200-H14 com espessura de 1 mm, estampadas e soldadas em simetria, a fim de que na união das chapas sejam deixados canais para passagem de água. Neste estudo foi realizada a caracterização do material por Ensaio de Tração e Ensaio Nakajima. Para determinação dos parâmetros de Estampagem Incremental foram realizados 16 experimentos com ferramenta de diâmetro df = 9,5 mm, variando a rotação de N = 50 rpm a 800 rpm e o incremento vertical de Δz = 2 mm a 0,2 mm, mantendo o avanço em = 250 mm/min. E também foram realizados 3 experimentos com ferramenta df = 22 mm, variando o incremento vertical de Δz = 2 mm a 0,5 mm, mantendo a rotação em N = 50 rpm e o avanço em = 250 mm/min. Para determinação dos parâmetros de Soldagem FSW foram realizados 4 experimentos com ferramenta de ombro de diâmetro 8 mm e pino roscado M3x0,5, mantendo a rotação em N = 1500 rpm e variando o avanço entre = 100 mm/min a 400 mm/min. Em seguida foi fabricado um protótipo de placa absorvedora de coletor solar com área de 0,12 m². Nos experimentos realizados foi constatado que é possível obter maiores deformações na Estampagem Incremental do que na Estampagem Convencional e que as deformações são mais elevadas quando se utiliza menores diâmetros, maiores rotações e menores incrementos verticais da ferramenta. Na Soldagem FSW não foi constatada influência na qualidade do cordão de solda em relação à variação do avanço da ferramenta. Neste estudo também se verificou que é possível fabricar protótipos de placas absorvedoras de coletores solares pelos processos de Estampagem Incremental e Soldagem FSW. No entanto, para coletores em tamanho comercial, novos estudos são necessários para melhorar a forma de fixação das chapas durante a Soldagem FSW. / This work presents an innovative model of flat plate solar collector, with absorber plate manufactured using Incremental Sheet Forming (ISF) and Friction Stir Welding (FSW). This absorber plate consists of two AA1200-H14 aluminum sheets with a thickness of 1 mm, stamped and welded in symmetry, in order to leave channels for the passage of water. In this study the characterization of the material by Nakajima Test and Traction Test was performed. In order to determine the parameters of ISF, 16 experiments were performed with a tool of diameter df = 9.5 mm, varying the rotation speed of N = 50 rpm at 800 rpm and the step down of Δz = 2 mm to 0.2 mm, maintaining the feed rate at = 250 mm/min. Also, 3 experiments with tool df = 22 mm were performed, varying the step down of Δz = 2 mm to 0.5 mm, maintaining the rotation speed at N = 50 rpm and the feed rate at = 250 mm/min. For determination of FSW parameters, 4 experiments with 8 mm diameter shoulder tool and M3x0.5 pin were performed, maintaining the rotation speed at N = 1500 rpm and varying the feed rate from = 100 mm/min to 400 mm/min. A prototype solar collector absorber plate with a 0.12 m² area was then manufactured. In the experiments carried out, it was found that it is possible to obtain greater deformations in the ISF than in the Conventional Stamping and that the deformations are higher when using smaller diameters, higher rotations and smaller step downs of the tool. In FSW, no influence was observed in the quality of the weld bead in relation to the variation of the tool feed rate. In this study it was also verified that it is possible to manufacture prototypes of solar collector absorber plates by the processes of ISF and FSW. However, for commercial size collectors, further studies are needed to improve the way the plates are fixed during FSW.

Submitted by Maicon Juliano Schmidt (maicons) on 2015-07-08T14:09:52Z No. of bitstreams: 1 Daniel dos Santos Silva.pdf: 1207479 bytes, checksum: a37801e7a4a9fabd110fb80d5c179a85 (MD5) / Made available in DSpace on 2015-07-08T14:09:52Z (GMT). No. of bitstreams: 1 Daniel dos Santos Silva.pdf: 1207479 bytes, checksum: a37801e7a4a9fabd110fb80d5c179a85 (MD5) Previous issue date: 2012-01-31 / Nenhuma / O uso da energia solar, como alternativa energética renovável, tem tomado um destaque fundamental no cenário mundial. Em especial, esse tipo de energia utilizado para aquecimento de água, tanto para uso doméstico como industrial representa um mercado mundial com crescimento em torno de 15% ao ano. No Brasil, esse crescimento deve-se, principalmente, aos programas habitacionais patrocinados pelo governo federal, além dos apelos cada vez mais fortes no sentido de buscar-se uma sustentabilidade energética e de economia através da diminuição do consumo de eletricidade e gás. Um sistema de aquecimento de água com energia solar é composto basicamente por coletor e reservatório térmico. Esses dois componentes representam quase a totalidade dos custos de instalação e isso ocorre principalmente em função dos materiais utilizados (cobre, alumínio e aço inoxidável) e dos processos de fabricação utilizados. Uma das formas para reduzir esses custos é a utilização de outros materiais mais baratos para a confecção de coletores e reservatórios e também de novos processos, mais ágeis e autômatos.Para contribuir com a solução desse problema, esse trabalho apresentará o desenvolvimento de uma ferramenta computacional que facilite a avaliação do rendimento térmico de diferentes composições de coletores solares de placa plana. Essa ferramenta foi desenvolvida sobre a plataforma EES (Engineering Equation Solver), pela sua facilidade de implementação, disponibilidade de funções de propriedades térmicas de fluidos, materiais e de escoamento. O programa segue um modelamento matemático baseado na teoria de Hottel-Bliss_Whillier e permite a entrada de dados relacionados aos parâmetros construtivos do coletor, como diâmetro dos tubos e espaçamento, espaçamento absorvedor-cobertura, material dos tubos, material da placa coletora e espessuras, material da cobertura e espessuras de isolamento, além de variáveis ambientais. Como dados de saída o programa fornece o desempenho térmico do coletor, calor útil, perdas térmicas, temperatura de estagnação, entre outros dados fundamentais de projeto. Os modelos matemáticos adotados na construção do programa foram validados através do confronto dos resultados calculados com dados obtidos experimentalmente em testes realizados pelo Test Center for Thermal Solar Systems do Fraunhofer Institut Solare Energie Systeme e pelo Institut für Thermodynamik und Wärmetechnik. Após a validação, a ferramenta é utilizada para avaliar o rendimento térmico de coletores com outros materiais construtivos, características óticas e termodinâmicas e também aspectos construtivos como a otimização do espaçamento de tubos, distanciamento entre cobertura e placa coletora, entre outros apresentados no capítulo quatro. / The use of solar energy as an alternative renewable energy, has taken a key highlight in the scene in different parts of the world. In particular, this type of energy used for heating water for domestic use becomes for a growing world market, mainly due to housing programs sponsored by the federal appeals beyond the increasingly strong in the sense of trying to achieve a sustainable energy and economy by reducing the consumption of electricity and gas. A system for heating water with solar energy is basically composed of collector and storage tank. These two components account for almost the entire cost of installation and this is mainly due to the materials (copper, aluminum and stainless steel) and the manufacturing processes used. One way to reduce these costs is the use of other cheaper materials for the manufacture of collectors. and reservoirs as well as new processes, more agile. To contribute to solving this problem, the present study the development of a software tool that facilitates the evaluation of the thermal efficiency of different compositions of flat plate solar collectors. This tool was developed on the platform EES (Engineering Equation Solver) for its ease of implementation, availability of functions of the thermal properties of fluids, materials and marketing.the program follows a mathematical model based on the theory of Hottel-Bliss_Whillier and allows entry of data related to the construction parameters of the collector, such as pipe diameter and spacing, spacing absorber-cover, the pipe material, the absorber material and thickness of material coverage and thickness of isolation and environmental variables. As output data the program provides the thermal performance of the collector, useful heat, thermal losses, stagnation temperature, and other fundamental data design.the mathematical models adopted in the construction of the program were validated by comparing the calculated results with data obtained experimentally by renowned research centers in Germany, as test center for thermal solar systems of Fraunhofer Institut Solare Systeme and Institut für Energie und Wärmetechnik Thermodynamik. After validation, the tool is used to evaluate the thermal performance of collectors with other building materials, optical characteristics and thermodynamic aspects of construction as well as the optimization of the spacing tubes, distance between absorber plate and cover, among others presented in chapter four.

Um modelo experimental de arco dentário, moldado em epóxi, foi utilizado para estudar o comportamento mecânico do copolímero de etileno e acetato de vinila (EVA), na forma de placa plana e protetor bucal. O modelo experimental foi investigado, usando-se um sistema configurado em duas formas diferentes: suporte + arco + placa plana e suporte + arco + protetor bucal. O comportamento mecânico do copolímero de etileno e acetato de vinila foi estudado em função de três variáveis: espessura, temperatura e na ausência e presença de saliva artificial. A avaliação do comportamento mecânico do EVA, na forma de placa e protetor, foi feita usando-se dois planejamentos estatísticos fatoriais, 3x2x2 e 23, respectivamente, numa máquina universal de tração. As propriedades mecânicas do EVA, ao esforço compressivo, avaliadas nas duas configurações (suporte + arco + placa e suporte + arco + protetor) foram: energia aparente absorvida (J.mm-1), tensão máxima (N.mm-1), deslocamento máximo (mm) e força máxima (N). Os efeitos das variáveis, espessura, temperatura e presença ou ausência da saliva artificial foram modelados, matematicamente, usando-se as propriedades mecânicas do EVA ao esforço compressivo, como parâmetros de resposta. Os polinômios ortogonais foram ajustados em função das variáveis e de suas interações significantes, fixando-se o nível de significância igual ou menor de 0,05 ou 5%. Um mecanismo de oclusão do modelo experimental, para explicar a resposta mecânica do EVA, no sistema suporte + arco + placa e suporte + arco + protetor, consistiu em três eventos acoplados: 1) deformação compressiva longitudinal; 2) escorregamento entre os arcos e 3) travamento mecânico ao atingir a máxima oclusão. As variáveis, espessura da placa ou do protetor, temperatura (ambiente e bucal) e saliva (ausência ou presença), bem como algumas interações significantes entre elas, modificaram as propriedades mecânicas do EVA, no sentido de aumentar ou reduzir a resistência oferecida, por este material, ao esforço compressivo, dependendo de como os níveis das respectivas variáveis eram combinados. A resposta mecânica do EVA no sistema suporte + arco + protetor diferiu do sistema suporte + arco + placa, pois os intervalos de espessuras médias dos protetores e das placas foram significativamente diferentes. O mecanismo de oclusão do modelo experimental proposto justifica as diferenças de comportamento mecânico observadas para as duas configurações estudadas. Para placas ou protetores mais finos, da ordem de 2mm, o escorregamento acoplado ao travamento mecânico foram dois eventos determinantes. Para as placas mais espessas, da ordem de 4 mm, o comportamento mecânico pode ser explicado por três eventos acoplados: deformação compressiva longitudinal, escorregamento entre os arcos e travamento mecânico, ao atingir a máxima oclusão. / An experimental model of dental arch, moulded in epoxy, was used to study the mechanic behaviour of a copolymer of ethylene and vinyl acetate (EVA), in the form of a flat plaque or mouth protector in function of three variables: thickness, temperature and the absence or presence of artificial saliva. The evaluation of the mechanical behaviour of EVA, as a plaque or as a mouth protector, was made with the use of two factorial statistical projection, 3x2x2 and 23, respectively, in a universal test machine. The mechanic properties of EVA, at compressive effort, evaluated in two configurations (support + arch + plaque and support + arch + mouth protector) were: maximum absorbed energy (J.mm-1), maximum strain (N.mm-1), maximum displacement (mm) and maximum force (N). The effect of the variables (thickness, temperature and absence or presence of artficial saliva) were shaped, mathematically, by using the mechanical properties of EVA to compressive effort as a reply parameter. The orthogonal polynomials were adjusted in function of the variables and their significant interactions, fixing the level of significancy as 0,05 (5%) or less. A mechanism of occlusion of the experimental model, to explain the mechanic answer of EVA in the system support + arch + plaque and support + arch + protector, consisted of three connected events: 1) longitudinal compressive deformation; 2) sliding between the arches and 3) mechanic lockage on maximum occlusion. The variables, thickness of the plaque or mouth protector, temperature (local or mouth) e saliva (presence or absence), as well as some significant interactions between them, modified the mechanic properties of EVA, in the sense of increasing or reducing the resistence of this material to the compressive effort, depending on the way these variables were combined. The mechanic answer of EVA in the system support + arch + mouth protector differed from the system support + arch + plaque, as the intervals of average thickness of the mouth protectors and of the plaque were significantly distinct. The mechanism of occlusion of the experimental model proposed justifies the differences of mechanical behaviour observed in both configurations studied. In thinner plaques or mouth protectors, approximately of 2 mm, the sliding connected to the mechanic lockage were two determinant events. For thicker plaques, approximately of 4 mm, the mechanical behaviour can be explained by three linked events: longitudinal compressive deformation, sliding between the arches and mechanic locakge, on the maximum occlusion.

Os elementos de combustível de um reator nuclear de pesquisa tipo MTR (\"Material Testing Reactor\") são, em sua grande maioria, formados por placas de combustível revestidas com alumínio contendo no cerne silicileto de urânio (U3Si2) disperso em matriz de alumínio. Essas placas possuem espessura da ordem de milímetros e comprimentos muito maiores em relação à sua espessura. Elas são dispostas paralelamente no conjunto que forma o elemento combustível, de maneira a formar canais entre elas com poucos milímetros de espessura, por onde escoa o fluido de refrigeração (água leve ou água pesada). Essa configuração, associada à necessidade de um escoamento com altas vazões para garantir o resfriamento das placas em operação, pode gerar problemas de falhas mecânicas das placas de combustível devido às vibrações induzidas pelo escoamento nos canais e, consequentemente, acidentes de proporções graves no caso de velocidade crítica que possa gerar o colapso das placas. Embora não haja ruptura das placas de combustível durante o colapso, as deflexões permanentes excessivas das placas podem causar bloqueio do canal de escoamento no núcleo do reator e levar ao superaquecimento nas placas. Para este trabalho, foram desenvolvidas uma bancada experimental com capacidade para altas vazões volumétricas (Q=100 m3/h) e uma seção de testes que simula um elemento combustível do tipo placa com três canais de resfriamento. A seção de testes foi construída com placas de alumínio e acrílico e foi instrumentada com sensores de deformação, sensores de pressão, um acelerômetro e um tubo de pitot. As dimensões da seção de testes foram baseadas nas dimensões do Elemento Combustível do Reator Multipropósito Brasileiro (RMB), cujo projeto está sendo coordenado pela Comissão Nacional de Energia Nuclear - CNEN. Os experimentos realizados alcançaram o objetivo de chegar à condição de velocidade crítica de Miller com o colapso das placas. A velocidade crítica foi atingida com 14,5 m/s levando a consequente deformação plástica das placas que formam o canal do escoamento. O canal central na entrada da seção de testes apresentou uma abertura de 3 mm em seu centro, causando um grande bloqueio do escoamento nos canais laterais. Este comportamento foi v constatado visualmente durante a desmontagem da seção de testes, ilustrado e discutido na análise de resultados apresentado neste trabalho. O bloqueio dos canais também foi observado por meio de gráficos de queda de pressão e por gráficos das deformações da entrada, centro e saída das placas contra a velocidade média da seção de testes. Observou-se uma queda da resistência hidráulica da seção de testes devido ao aumento da seção transversal de escoamento no canal central e um aumento exponencial das deformações quando da ocorrência da velocidade crítica. Comparativamente, o valor experimental obtido para velocidade crítica na seção de testes foi da ordem de 85% do valor obtido por cálculo com a expressão teórica de Miller. Os experimentos realizados permitiram um melhor entendimento da interação fluido estrutura em elementos de combustível tipo placa como: valores de frequências de vibrações naturais, instabilidade fluido elástica e desenvolvimento de técnicas para a detecção de valores de velocidade crítica. / The fuel elements of a MTR (Material Testing Reactor) type nuclear reactor are mostly composed of aluminum-coated fuel plates containing the core of uranium silica (U3Si2) dispersed in an aluminum matrix. These plates have a thickness of the order of millimeters and are much longer in relation to their thickness. They are arranged in parallel in the assembly forming the fuel element to form channels between them a few millimeters in thickness, through which there is a flow of the coolant (light water or heavy water). This configuration, combined with the need for a flow at high flow rates to ensure the cooling of the fuel element in operation, may create problems of mechanical failure of fuel plate due to the vibration induced by the flow in the channels. In the case of critical velocity may cause collapse of the plates. Although there is no rupture of the fuel plates during collapse, excessive permanent deflections of the plates can cause blockage of the flow channel in the reactor core and lead to overheating in the plates. For this study were developed an experimental bench capable of high volume flows (Q = 100 m3/h) and a test section that simulates a plate-like fuel element with three cooling channels. The test section was constructed with aluminum and acrylic plates and was instrumented with straingauge sensors, pressure sensors, accelerometer and a tube of pitot. The dimensions of the test section were based on the dimensions of the Fuel Element of the Brazilian Multipurpose Reactor (RMB), whose project is being coordinated by the National Commission of Nuclear Energy (CNEN). The experiments performed attained the objective of reaching Miller\'s critical velocity condition with the collapse of the plates. The critical velocity was reached with 14.5 m/s leading to the consequent plastic deformation of the plates forming the flow channel. The central channel had a 3mm aperture in its center, causing a large blockage of the flow in the lateral channels. This behavior was observed visually during the disassembly of the test section, illustrated and discussed in the results analysis presented in this work. Blocking of the channels was also observed by means of graphs of pressure drop and graphs of the deformations of the entrance, center and exit of the plates against the average speed vii of the section of tests. It was observed a decrease of the hydraulic resistance of the section of tests due to the increase of the transversal section of flow in the central channel and an exponential increase of the deformations when the critical speed occurrence. Comparatively, the value obtained for critical velocity in the test section through the experiments was of the order of 85% of the value obtained by calculation with Miller\'s theoretical expression. The experiments allowed a better understanding of the structure fluid interaction in plate type fuel elements such as: natural vibration frequency values, elastic fluid instability and development of techniques for the detection of critical velocity values.