Yes / CO2 capture from natural gas was experimentally and theoretically studied using a dead-end polymeric permeation cell. A numerical model was proposed for the separation of CO2/CH4 using Polytetrafluoroethylene (PTFE) in a flat sheet membrane module and developed based upon the continuity, momentum and mass transfer equations. The slip velocity condition was considered to show the reflection of gas flow in contact with the membrane surface. The solution method was based on the well-known SIMPLE algorithm and implemented using MATLAB to determine the velocity and concentration profiles. Due to change in velocity direction in the membrane module, the hybrid differencing scheme was used to solve the diffusion-convection equation. The results of the model were compared with the experimental data obtained as part of this work and good agreement was observed. The distribution of CO2 concentration inside the feed and permeate chambers was shown and the velocity profile at the membrane surface was also determined using reflection factor for polymericmembrane. The modelling result revealed that increasing the amount of CO2 in gas feed resulted in an increase in the CO2 in the permeate stream while the gas feed pressure increased. By changing the permeability, the model developed by use of the solution-diffusion concept could be used for all polymeric membranes with flat sheet modules.

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No. of bitstreams: 1 coaguilanunez_dn_dr_ilha.pdf: 7476556 bytes, checksum: 22e091cc3eb8948aa1965629836090d4 (MD5) Previous issue date: 2017-01-27 / Outra / Em cenários de mudanças climáticas e de uso e ocupação do solo, a bacia do córrego Cabeceira Comprida, localizada em Santa Fé do Sul - SP, se apresenta degradada com talvegues assoreados, ausência de matas ciliares e nascentes desprotegidas levando à incapacidade de gerar e armazenar água para atender a demanda atual (população, agricultura e saneamento) e em períodos de seca, agravando-se em prolongadas estiagens, como em 2004, 2013 e 2014 agravando o problema do abastecimento de água à população. Sendo assim, torna-se importante avaliar os fluxos hídricos da água acima do solo na bacia com o uso combinado de imagens de satélites Landsat 5 (TM) e Landsat-8 (OLI e TIRS) no período de 2000 - 2011 e 2013 - 2015 e informações provenientes de estações agrometeorológicas. Para tanto, utilizou-se o modelo Simple Algorithm for Evapotranspiration Retrieving (SAFER) para estimativa da evapotranspiração atual (ETa), resultando em uma média da bacia no período avaliado de 0,70 mm dia-1, 0,85 mm dia-1 das espécies invasoras (EI), 1,20 mm dia-1 da mata remanescente (MR), 0,70 mm dia-1 da pastagem (Pa), 0,65 mm dia-1 das culturas anuais (CA) e 0,72 mm dia-1 das culturas perenes (CP). O ano de 2003 registrou a menor média de ETa da bacia com 0,42 mm dia-1, enquanto o ano de 2015 apresentou a maior média anual do período estudado, com 1,03 mm dia-1. Destaca-se que os valores da ETa das EI equivale ao consumo de 25% da população de Santa Fé do Sul, o que traz consequências na época seca quando o recurso hídrico é mais escasso. Estes cenários exigem ações imediatas para a produção e armazenamento de água na bacia, que tem morfometria alongada, evidenciando menor risco de cheias em condições normais de pluviosidade anual. A declividade média de 5,4% caracteriza o relevo como suave-ondulado, com drenagem deficiente (1,054 km km-2). Com essas características morfométricas associadas à precipitação anual média de 1.271 mm e padrão de drenagem caracterizado como do tipo dendrítico, com baixo grau de ramificação (Ordem 3), a disponibilidade de água não deveria ser um problema, mas o é, pelo fato de que a bacia se encontra degradada com apenas 4,5% de MR, os serviços ecossistêmicos fornecidos pela vegetação natural são mínimos e insuficientes para atender a demanda de água por parte dos usuários. São necessárias a adoção de medidas de mitigação, incluindo intervenção e implementação ações como por exemplo, o pagamento por serviços ambientais, sendo uma medida urgente a preservação ou recomposição da mata ciliar. / In a scenario of climate change and land use and occupation, the watershed of Cabeceira Comprida stream, located in Santa Fé do Sul - São Paulo State, presents as degraded with thalwegs sedimented, absence of riparian forests and unprotected springs leading to the inability to generate and store water to meet current demand (population, agriculture and sanitation) in periods of drought, aggravating in prolonged droughts, such as those of 2004, 2013 and 2014 exacerbating the problem of water supply to the population. Being necessary to evaluate the behavior of above-ground water in the watershed with combined use of Landsat 5 (TM) and Landsat - 8 images (OLI and TIRS) in the period of 2000 - 2011 and 2013 - 2015 and information from agrometeorological stations. Therefore, we used the Simple Algorithm for Retrieving Evapotranspiration (SAFER) to estimate actual evapotranspiration, resulting in average basin during the study period of 0.70 mm dia-1, 0.85 mm dia-1 of invasive species (EI), 1.20 mm dia-1 of the remaining forest (MR), 0.70 mm dia-1 of pasture (Pa), 0.65 mm dia-1 of annual crops (CA) e 0.72 mm dia-1 of perennial crop (CP). The year 2003 recorded the lowest average evapotranspiration of the basin with 0.42 mm dia-1, while the year 2015 had the highest annual average in the study period with 1.03 mm dia-1. It is worth noting that the evapotranspiration of the IE corresponds to the consumption of 25% of the population of Santa Fé do Sul, which has consequences in the dry season when the water resource is scarcer, requiring immediate actions for the production and storage of water in the watershed, which has an elongated morphometry, showing a lower risk of flooding under normal annual rainfall conditions. The mean slope of 5.4% is characterized by a smooth-wavy relief with poor drainage (1.054 km km-2). With these morphometric characteristics associated to the average annual precipitation of 1,271 mm and drainage pattern characterized as dendritic type, with low degree of branching (Order 3), the availability of water should not be a problem, but it is due to the fact that the watershed is degraded with only 4.5% of remaining forest, the ecosystem services provided by natural vegetation are minimal and insufficient to meet users' water demand. It is necessary to adopt mitigation actions, including intervention and implementation actions such as payment for environmental services, being an urgent measure the preservation or restoration of the riparian forest.

Orientador: Fernando Braz Tangerino Hernandez / Resumo: Em cenários de mudanças climáticas e de uso e ocupação do solo, a bacia do córrego Cabeceira Comprida, localizada em Santa Fé do Sul - SP, se apresenta degradada com talvegues assoreados, ausência de matas ciliares e nascentes desprotegidas levando à incapacidade de gerar e armazenar água para atender a demanda atual (população, agricultura e saneamento) e em períodos de seca, agravando-se em prolongadas estiagens, como em 2004, 2013 e 2014 agravando o problema do abastecimento de água à população. Sendo assim, torna-se importante avaliar os fluxos hídricos da água acima do solo na bacia com o uso combinado de imagens de satélites Landsat 5 (TM) e Landsat-8 (OLI e TIRS) no período de 2000 - 2011 e 2013 - 2015 e informações provenientes de estações agrometeorológicas. Para tanto, utilizou-se o modelo Simple Algorithm for Evapotranspiration Retrieving (SAFER) para estimativa da evapotranspiração atual (ETa), resultando em uma média da bacia no período avaliado de 0,70 mm dia-1, 0,85 mm dia-1 das espécies invasoras (EI), 1,20 mm dia-1 da mata remanescente (MR), 0,70 mm dia-1 da pastagem (Pa), 0,65 mm dia-1 das culturas anuais (CA) e 0,72 mm dia-1 das culturas perenes (CP). O ano de 2003 registrou a menor média de ETa da bacia com 0,42 mm dia-1, enquanto o ano de 2015 apresentou a maior média anual do período estudado, com 1,03 mm dia-1. Destaca-se que os valores da ETa das EI equivale ao consumo de 25% da população de Santa Fé do Sul, o que traz consequências na época seca quand... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In a scenario of climate change and land use and occupation, the watershed of Cabeceira Comprida stream, located in Santa Fé do Sul - São Paulo State, presents as degraded with thalwegs sedimented, absence of riparian forests and unprotected springs leading to the inability to generate and store water to meet current demand (population, agriculture and sanitation) in periods of drought, aggravating in prolonged droughts, such as those of 2004, 2013 and 2014 exacerbating the problem of water supply to the population. Being necessary to evaluate the behavior of above-ground water in the watershed with combined use of Landsat 5 (TM) and Landsat - 8 images (OLI and TIRS) in the period of 2000 - 2011 and 2013 - 2015 and information from agrometeorological stations. Therefore, we used the Simple Algorithm for Retrieving Evapotranspiration (SAFER) to estimate actual evapotranspiration, resulting in average basin during the study period of 0.70 mm dia-1, 0.85 mm dia-1 of invasive species (EI), 1.20 mm dia-1 of the remaining forest (MR), 0.70 mm dia-1 of pasture (Pa), 0.65 mm dia-1 of annual crops (CA) e 0.72 mm dia-1 of perennial crop (CP). The year 2003 recorded the lowest average evapotranspiration of the basin with 0.42 mm dia-1, while the year 2015 had the highest annual average in the study period with 1.03 mm dia-1. It is worth noting that the evapotranspiration of the IE corresponds to the consumption of 25% of the population of Santa Fé do Sul, which has consequences in the d... (Complete abstract click electronic access below) / Doutor

The main purpose of this research is to develop a Computational Fluid Dynamics (CFD) software to be used as an educational tool in teaching introductory level fluid mechanics and CFD courses. The software developed for this purpose is called Virtual Flow Lab. It has a graphical user interface (GUI) that enables basic pre-processing, solver parameter and boundary condition setting and post-processing steps of a typical CFD simulation. The pressure-based solver is capable of solving incompressible, laminar, steady or time-dependent problems on two-dimensional Cartesian grids using the SIMPLE algorithm and its variants. Blocked-cell technique is implemented to extend the types of the problems that can be studied on a Cartesian grid. A parametric study is conducted using a number of benchmark problems in order to test the accuracy and efficiency of the solver and successful results are achieved.

In this thesis, we have evaluated a stochastic Lagrangian model for computing particle deposition rates with prospects to use for atmospheric deposition applications.  The model is one-dimensional and models the particle dynamics in the boundary layers near walls and obstacles by simulating the coherent turbulent structures and Brownian motion governing the wall-normal transport. The deposition model is used with a hybrid deterministic/stochastic particle dispersion model governing the dynamics in the turbulent bulk flow. We used a steady-state RANS k-ϵ turbulence model to simulate the turbulent fluid flow in a neutral atmospheric boundary layer (ABL) using the with inflow boundary conditions by Richards & Hoxey (1993). The turbulence model is solved with the SIMPLE algorithm using the OpenFOAM software. The mean-field characteristic of the turbulent flow in the computational domain is exported and used for the particle model. The particle model is a Lagrangian Langevin-type model, consisting of a system of stochastic differential equations. The particle model was solved using a weakly first order a-stable scheme. We evaluated the deposition model by computing the deposition rate for a range of particle sizes and compared our results with collected experimental wind tunnel data. The numerical experiment was done in a computational domain based on the ABL model by Hargreaves & Wright (2007), a rectangular domain with a logarithmic wind profile. We used a particle source near the inflow boundary with an instantaneously release at the initial time. Results showed disagreement with the experimental data and was only valid for medium sized particles. However, time restrictions led to the analysis being cut short and only a single simulation was conducted. A definite conclusion on the suitability of the method could not be made based solely on this single results. Some uncertainties were identified and discussed for further potential work on the evaluation of the method. However, one conclusion was drawn on the performance of the method. The computational cost was concluded to be too high with the first order particle scheme used and higher order schemes is required for any practical use of the method for atmospheric deposition applications.