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This research was conducted in the urban area of the municipality of Crato-CE in the Cariri. The study anger dealing with the application of a hydraulic model for runoff and free channels in a channel that winds masonry part of the urbanized area of the city center and over the years has been occurring flood events due to variable rainfall in the city. The work done included field visits possession of equipment for conducting surveys, measurements of flow, collecting images and measurement field. The information obtained from this study will be a bibliographic database to contribute to the advancement of research and provision of data for better planning and management of water resources site. / Esta pesquisa foi desenvolvida na zona urbana do municÃpio de Crato-CE na regiÃo do Cariri. O estudo tratou da aplicaÃÃo de um modelo hidrÃulico para escoamento em canais livres em um canal de concreto que percorre parte da Ãrea urbanizada do centro da cidade e que ao longo dos anos vem ocorrendo eventos de inundaÃÃo por conta das variÃveis precipitaÃÃes no municÃpio. O trabalho elaborado contou com visitas em campo de posse de equipamentos para realizaÃÃo de levantamentos topogrÃficos, aferiÃÃes de vazÃes, coleta de imagens e mensuraÃÃo de campo. As informaÃÃes obtidas nessa pesquisa servirÃo de base bibliogrÃfica para contribuir no avanÃo de pesquisas e fornecimento de dados para um melhor planejamento e gerenciamento dos recursos hÃdricos local.

In this study a three-dimensional mathematical model is developed to simulate the flow field and mass transfer in a PEM fuel cell. In the model, the effects of the different flow channel structures in heterogeneous composite carbon fiber bipolar plates and traditional hard surface bipolar plates on the performance are studied. The results show that, the cell performance with the heterogeneous composite carbon fiber bipolar plates have better performance than that with the traditional hard surface bipolar plates, whether in the parallel flow channel structures or the serpentine flow channel structures. The reason is that, the heterogeneous composite carbon fiber ribs are porous material, so it allows the reactants and products transport uniformly even in the rib zone. This greatly improved the mass transfer and the gases distribution in the fuel cell. With the traditional bipolar plates, the reactants can only enter the reaction zone from the side of carbon cloth under ribs, so that the performance in this area under rib is relatively poor. In the simulation of the flow channel structures, we detect that, due to the single inlet serpentine flow channel have stronger convective effects that forced reactants to flow through the whole reaction zones, so it has better performance at high current density than in the singles inlet parallel flow channel. In addition, the results also show that, higher fuel stoichiometric number and operated pressure and properly humidified at anode will all improve the performance of the fuel cell.

In general, a PEMFC was assembled by using a number of locked bolts. But this assembly will cause concentrated loads existed on the upper and lower portions of the end plates, so that the pressure distributed non-uniformly at the internal structures in the PEMFC and thus causing uneven distributed deformations of flow-channel plates. This phenomenon may lead to the leak of reaction gas, and causing not only the decrease of the efficiency of PEMFC, but also the increase of the dangerous. If the fuel cell size getting smaller, the influence may be more severely. The main aim of this study is to simulate the response of a micro-PEMFC numerically by utilizing a 3-D FEM model while the micro-PEMFC was assembled by three pairs of bolts along the upper and lower portions, respectively, of the end plates. The effects of different bolts locking sequences on the deformation and pressure distributions at flow-channel plates and on the porosity of gas diffusion layers in the micro-PEMFC were investigated. The simulated results showed that if one locked the middle bolt either on the upper or lower portion first, then the obtained uniformities of warpage, deformation, von Mises stress and porosity were superior than the corresponding obtained results if one locked either one of the four corner bolts first. Also, among the three pairs of bolts used for assembling the cell, the first locking bolt of the first pair of locking bolts and the first locking bolt of the rest of two pairs of locking bolts were suggested on the reverse portions of the end plates.

The design and method of cell assembly plays an important role in the performance of PEM fuel cell. The cell assembly will affect the contact behavior between the bipolar plates, flow-channel plates, gas diffusion layers (GDLs) and membrane electrode assembly (MEA). From the past studies, it was noted that the flow-channel plates in the cell will be deformed while the cell was assembled by locking with bolts. This phenomenon may lead to leakage of fuels, high contact resistance and malfunctioning of the cells. The main aim of this research is to study the variation of the deformation mode of the flow-channel plat in a micro-PEM fuel cell assembly subjected to different bolts locking sequences. The commercial FEM package, ANSYS, was adopted to model the three-dimensional single micro-PEMFC FEM model and the numerical simulation analyses were performed. The effect of the bolts locking sequence on the deformations of flow-channel plate in the micro-PEMFC was presented. A most properly bolts locking sequence was proposed also.

The current stimuli of climate change and rising oil prices have spurred the development of hybrid electric (HEV), and battery electric vehicles (BEV): collectively termed EVs. However, the battery technology needs much development: at the time of writing, the range of a BEV is too low to be practical in many situations. A critical limitation is the sensitivity of batteries to temperature: the heat generated during operation affects their performance and reduces the lifetime. This study investigates battery cooling using cooling plates: thin rectangular fabrications inserted between battery cells. A coolant pumped through internal channels absorbs heat and transports it away from the battery. Previous studies of liquid heat exchangers have indicated that the geometry of the channels plays a significant role in the performance; however, there is a lack of rigorous numerical optimization applied to EV cooling plates. By developing a numerical optimization framework utilizing parametric geometry generation and computational fluid dynamics, this research has investigated the characteristics of optimum cooling plate geometry with respect to three objectives: average temperature, temperature uniformity, and coolant pressure drop. By applying each objective separately, improvements of up to 70% have been made compared to a reference design. The influence of boundary conditions on performance and optimum design has been assessed, and multi-objective optimization has investigated the trade-off between competing objective functions. Although care should be taken when extrapolating the results beyond the geometry and conditions in the study, some general design principles can be proposed. Objectives of average temperature and pressure drop can both be satisfied by a common design with wide cooling channels, but different characteristics are needed for temperature uniformity. Additional assessments have revealed that optimizations of temperature uniformity are especially sensitive to the boundary conditions, whereas the other objective functions are largely insensitive. The optimization process developed in this work can be applied to any potential cooling plate design and will lead to gains in the targeted performance measure. In doing so, the performance of the EV will be incrementally improved, thereby advancing the day when an EV is not only an environmental choice, but also a practical choice. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2011-09-07 16:24:14.6

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19681号 / 工博第4136号 / 新制||工||1638(附属図書館) / 32717 / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 西脇 眞二, 教授 稲室 隆二, 教授 松原 厚 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

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京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21753号 / 工博第4570号 / 新制||工||1712(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 西脇 眞二, 教授 松原 厚, 教授 黒瀬 良一 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23506号 / 工博第4918号 / 新制||工||1768(附属図書館) / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 中島 健, 教授 横峯 健彦, 准教授 山本 俊弘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM