The access to ideal heating and power techniques has always been highly thought after.This is mainly due to the development in housing architecture and the cold nature of certain regions which has led to an increase in popularity of the heating market and modernised heating technologies. The current DH systems make use of CHP plants for thegeneration of power and electricity. These CHP plants for the most part, are powered through biomass and during winter periods the demand for heating is highly increased.The biggest issue with relying on biomass solely is the constant need to burn wasteproducts which not only results in increasing the demand for consuming in more waste,but also results in producing remains (by-products) that cannot be broken down further and hence might require the utilization of land-space (landfills) for their disposal. Solar modules on the other hand, have gained increased popularity in the recent age. This is mainly due their extremely high flexible ability in converting solar irradiance intoelectrical and thermal energies. This study will try to provide a comprehensive study intothe utilization of a hybrid solar system that combines a standard PV module with a flat-plate collector through estimating the energy demands for a simple housing within Sweden and China. This will be the main aim of the study, however the possibilities of integrating this hybrid solar system alongside current DH systems will mostly be discussed in the first sections to proof the possibility of executing such a system. The theoretical work carried out will only include simulations of having just separate,standalone PV and flat-plate collector modules. However, designing a hybrid solar and DH system will not be the major focus of this study. The results at the end of the report,concluded that the electrical production for the Swedish case were noticeably higher thanthat of the Chinese case in spite of maintaining the same load values through both cases and higher solar irradiation for the Chinese case. Due to PVsyst simulation constraints,the results show that the investment cost of the Swedish PV (electrical component) module was about 3.6 times greater than that of the Chinese which could possibly mean that the Swedish case has a bigger PV module area than the Chinese case in order to meetel ectricity demand monthly. However, when it came to the thermal energy production, it was possible to assume different collectors cases and hence an area of 7m2 was chosen for the Swedish perspective while an area of 4m2 has been considered for the Chinese case. The thermal useful energy values where then compared with heating demands for both of the cases. Finally, the thesis concluded that there was no requirement for having an integrated DH network within the standalone houses, having small electricity and heat demand and hence, it might be more beneficial to have an integrated DH and solar system within more densely populated housing areas. / Efterfrågan på tillgången till idealisk uppvärmning och effektiva tekniker har alltid varithög. Detta beror främst på utvecklingen inom arkitektur och den kalla naturen i vissaregioner som har lett till en ökad popularitet av värmemarknaden och moderniseradevärmeteknologiert. De nuvarande fjärrvärme-systemen använder kraftvärmeverk förproduktion av kraft och elektricitet. Dessa kraftvärmeanläggningar drivs till stor delgenom biomassa och under vinterperioderna ökar efterfrågan på uppvärmning mycket.Det största problemet med att förlita sig på biomassa enbart är det ständiga behovet avatt bränna avfallsprodukter som inte bara resulterar i att öka efterfrågan på konsumtionav fler avfallsprodukter utan också resulterar i att producera rester (biprodukter) sominte kan brytas ned ytterligare och därmed kan kräva användning av markutrymme fördeponering. solar-moduler å andra sidan har ökat popularitet under de senaste åren.Detta beror främst på deras extremt höga flexibla förmåga att konvertera solbestrålningtill elektrisk och termisk energi. Denna studie kommer att försöka tillhandahålla enomfattande studie av användningen av ett hybridsolsystem som kombinerar en standardPV-modul med en flatplate collector för att simulera en solar-modul samt caselera enfristående version genom att uppskatta energikraven för en enkel bostad i Sverige ochKina. Detta kommer att vara huvudmålet med studien, men möjligheterna att integreradetta hybrida solsystem tillsammans med nuvarande DH-system kommer mestadels attdiskuteras i de första avsnitten för att bevisa möjligheten att utföra ett sådant system. Detteoretiska arbetet som utförs kommer endast att innehålla simuleringar av att bara ha enfristående PV- och flatplate collector module, men att utforma ett hybrid sol- och DHsystemkommer inte att vara huvudfokus för denna studie. Resultaten i slutet avrapporten drog överraskande slutsatsen att den elektriska produktionen för den svenskacaselen var märkbart högre än den för den kinesiska caselen trots att de båda caselernabibehöll samma belastningsvärden och högre solbestrålning för den kinesiska caselen.Detta kan förklaras av skillnaden i modulpriser vid simulering genom PVsyst därinvesteringskostnaden för den svenska PV-modulen (elektrisk komponent) var ungefär3,6 gånger större än den för kinesiska, vilket innebär att PVsyst antar ett störremodulområde för svensk modul och därmed mer energiproduktion. Men när det kom tillvärmeenergiproduktionen, var det möjligt att anta olika samlarfall och följaktligen valdesett område på 7m2 för det svenska perspektivet medan ett område på 4m2 har beaktatsför den kinesiska och värmevärden för användbar energi där jämfördes sedan med dekrav som krävs för uppvärmning i båda fallen. Slutligen drog avhandlingen slutsatsen attdet inte fanns något krav på att ha ett integrerat DH-nätverk i de fristående husen ochdärför kan det vara mer fördelaktigt att ha ett integrerat DH och solsystem i tätarebebyggda bostadsområden.

In this thesis, experimental and numerical studies have been carried out to investigate the performance of a solar desalination system working on humidification-dehumidification principle under the climatological conditions of Ankara, Turkey. The desalination unit was configured mainly by a double-pass flat plate solar air heater with two glass covers, pad humidifier, storage tank and dehumidifying exchanger. The system used in this work is based on the idea of closed water and open air cycles. A computer simulation program based on the mathematical model was developed by means of MATLAB software to study the effect of different environmental, design, and operational parameters on the desalination system productivity. In this simulation program, the fourth order Runge-Kutta method was used to solve the energy balance equations simultaneously and numerically. In order to compare the obtained theoretical results with experimental ones and validate of the developed mathematical model of the system, an experimental study has been carried out. For that, an experimental set-up was designed, constructed and tested at the solar house of the Mechanical Engineering Department of METU. In addition, the existing solar desalination system was integrated with an evacuated tubular solar water heater unit (closed water circulation) and performance of the system has been studied experimentally.

Traditionally, energy capture by non-concentrating solar collectors is calculated using the Hottel-Whillier Equation (HW): Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*(T(fi)-Tₐ), or its derivative: Q(u)=A(c)*F(r)*S-A(c)*F(r)*U(l)*((T(fi)-T(fo))/2-Tₐ). In these models, the rate of energy capture is based on the collector's aperture area (A(c)), collector heat removal factor (F(r)), absorbed solar radiation (S), collector overall heat loss coefficient (U(l)), inlet fluid temperature (T(fi)) and ambient air temperature (Tₐ). However real-world testing showed that these equations could potentially show significant errors during non-ideal solar and environmental conditions. It also predicts that when T(fi)-Tₐ equals zero, the energy lost convectively is zero. An improved model was tested: Q(u)=A(c)F(r)S-A(c)U(l)((T(fo)-T(fi))/(ln(T(fo)/T(fi)))-Tₐ) where T(fo) is the exit fluid temperature. Individual variables and coefficients were analyzed for all versions of the equation using linear analysis methods, statistical stepwise linear regression, F-Test, and Variance analysis, to determine their importance in the equation, as well as identify alternate methods of calculated collector coefficient modeling.

Natural convective heat transfer from flat plates and short cylinders inclined at an angle to the vertical in laminar and transition flow regions with isothermal or constant heat flux conditions have been numerically and experimentally studied. When the width of the plate is relatively small compared to its height, i.e., the plate is narrow, the heat transfer rate can be considerably greater than that predicted by these two-dimensional flow results. When the narrow plate is inclined to the vertical, pressure changes normal to the plate surface arise and these pressure changes can alter the nature and the magnitude of the edge effects. When two narrow inclined rectangular flat plates of the same size separated vertically or horizontally, the flow interaction between these heated plates can have a significant effect on the heat transfer. When relatively small square and circular cylinders with exposed top surfaces inclined to the vertical are used, the interaction of the flow over the surfaces that make up the cylinder and inclination angle have, in general, a considerable effect on the magnitude of the mean heat transfer rate and on the nature of the flow over the cylinder surfaces. In the present numerical studies it has been assumed that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated using the Boussinesq approach. The numerical solution was obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in dimensionless form. The solution was obtained using a commercial CFD code, FLUENT. Results were only obtained for a Prandtl number of 0.7; this being approximately the value of air. In the experimental studies, the average heat transfer rates from cylinders were determined by the transient method, which involves heating the model and then measuring its temperature-time variation while it cools. The average heat transfer rates from the flat plates were determined using a steady state method, which basically involved electrically heating the plate. The tests were carried out inside a large enclosure. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2011-06-27 19:27:45.724

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.

In this thesis report for Dalarna University in Borlange and Absolicon company the study of a possibility to add an array of concentrating solar collectors to a Torsång district heating system was done. The whole idea of this work was to make a simulation of this kind of system, trying to get 15-20% of solar fraction, and make an economical evaluation. At the same time, another goal was to make two comparisons: between concentrating and flat-plate collector in the same system, and between two tools for collector analysis – Polysun and Absolicon tool, based on TRNSYS, which was designed to estimate the output of the collector for a certain temperature, without any load. During the study, the analysis of the simulating tools was made and the combination of those two tools was used. Using long iteration cycles, involving changing the field layout, number of collectors and distance between collector rows in flat-plate collector case, both types of collectors were analyzed. The method of the analysis was to get an equal output of the field and see the differences, which appear while using different collector types.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / The using of alternatives materials to replace selective surfaces is a natural trend, because it usually looks for improvements on efficiency of surfaces at the same time that it tries to reduce costs. Composites are already used on obtainment of some selective surfaces, however, if the possibility to use residue that would be discarded was associated to these characteristics, providing an added-value, it would brings some benefits like a possible reduction of manufacturing costs. Thus, this thesis proposes the obtainment and study of selective surfaces for flat plate solar collectors for low cost by using residue from granite industry. Three different surfaces was studied, two of them of obtained on the laboratory, one is granite powder made and the other is a surface composed by a mixture of granite powder and CRFO (Cr0,75Fe1,25O3); the third surface is a commercial one, known as TiNOX. To perform the tests of the surfaces it was built an experimental stand, it allows simulating a solar collector conditions. The tests was performed in a stagnation condition, in other words, there wasnât any water flow inside tubes. Through this experimental apparatus it was possible to test the three surfaces simultaneously. The field tests showed that the highest temperatures were reached by granite powder surface, which reached an average temperature of 119 ÂC, while the granite powder and CRFO mixture surface reached an average of 96 ÂC. The TiNOX achieve an average temperature of 101 ÂC. The three surfaces was compared each other through an equation that gives a global heat loss coefficient. The granite powder surface was the one which achieved the lowest global heat loss coefficient. / O uso de materiais alternativos com objetivo de substituir superfÃcies seletivas à uma tendÃncia natural, pois geralmente se busca melhorias na eficiÃncia das superfÃcies ao mesmo tempo em que se tenta diminuir os custos. SubstÃncias compÃsitas jà sÃo utilizadas na obtenÃÃo de algumas superfÃcies seletivas, no entanto, se for associado a estas caracterÃsticas a possibilidade de utilizar resÃduos que iriam ser descartados, conferindo aos mesmos um valor agregado, isso traria alguns benefÃcios, como uma possÃvel reduÃÃo de custos de fabricaÃÃo. Desta forma, o presente trabalho propÃe a obtenÃÃo e o estudo de superfÃcies seletivas para aplicaÃÃes em coletores solares de placa plana de baixo custo originÃrio do resÃduo da indÃstria de granito. Foram estudadas trÃs diferentes superfÃcies, duas delas foram obtidas no laboratÃrio, a superfÃcie a base de pà de granito e a superfÃcie composta pela mistura de pà de granito e CRFO (Cr0,75Fe1,25O3); e a terceira superfÃcie foi uma superfÃcie comercial, conhecida como TiNOX. Para a realizaÃÃo dos testes foi construÃda uma bancada experimental de madeira, de forma que fosse possÃvel simular as condiÃÃes de um coletor solar de placa plana. Os testes foram feitos em condiÃÃo de estagnaÃÃo, ou seja, nÃo havia fluxo de Ãgua atravÃs de tubos no coletor. AtravÃs desse aparato experimental foi possÃvel testar as trÃs superfÃcies seletivas simultaneamente. Os testes de campo mostraram que a superfÃcie composta por pà de granito foi a que atingiu as maiores temperaturas, com uma mÃdia de atà 119 ÂC, enquanto a superfÃcie obtida com uma mistura de pà de granito e CRFO chegou a temperatura mÃdia de 96 ÂC, jà a superfÃcie comercial atingiu uma mÃdia de 101 ÂC. As superfÃcies foram comparadas atravÃs de uma equaÃÃo que fornece o coeficiente global de perda de energia tÃrmica. Os menores coeficientes foram obtidos pela superfÃcie de pà de granito

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / O estudo de superfÃcies seletivas para coletores solares tÃrmicos, hà alguns anos, enfoca o uso de pastas e tintas para recobrir chapas de cobre ou alumÃnio, formando a placa absorvedora do coletor. Essas tintas ou pastas sÃo eletrodepositadas em placas metÃlicas, sendo este processo muitas vezes responsÃvel pelo levado custo de superfÃcies seletivas. O uso de compÃsitos obtidos a partir do Ãxido de cromo, Ãxido de ferro e Ãxido de titÃnio em um processo cerÃmico, utilizando a tÃcnica de deposiÃÃo por screen-printing pode ser uma alternativa para a obtenÃÃo de novas superfÃcies seletivas que tenham eficiÃncia prÃxima Ãs tintas e pastas jà comercializadas e com baixo custo de fabricaÃÃo. O objetivo deste trabalho à obter e caracterizar superfÃcies seletivas à base de cromo, ferro e titÃnio e comparÃ-las com outras superfÃcies jà comercializadas (Ãxidos metÃlicos), encontrar os valores da absortividade e caracterizar as mesmas por espectroscopÃa raman e infavermelho. / The study of selective coating for thermal solar collectors has been carried out with focus on the use of selective paints and coatings for copper and aluminum plates, which are used to manufacture the absorber plate. The processes, such as electrodeposition, used in these paints and coatings are expensive and they increasing the price of the final product. The use of composite obtained from chromium oxide, iron oxide, and titanium oxide in a ceramic process using the screen-printing deposition technique is an alternative to develop new selective coating with approximately the same thermal efficiency, but at a lower cost than the commercial ones. The results show that the absorptivity values measured with the new coatings are close to those presented by the manufacturers in the commercial sufaces. The objective is to obtain and characterize selective surfaces based on chromium, iron and titanium and compares them to other areas already marketed (metal oxides), find the values of absorptivity and characterize them by raman and infrared spectroscopy.

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.