Título: | INFLUENCE OF TEMPERATURE AND CHROME DOPANTS IN CONFIGURATIONAL TRANSIENT DIFFUSION OF IRON OXIDE IN HIGH ALUMINA POROUS REFRACTORY MATRIX | ||||||||||||
Autor: |
CARLOS EDUARDO GUEDES CATUNDA |
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Colaborador(es): |
ROBERTO RIBEIRO DE AVILLEZ - Orientador |
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Catalogação: | 11/MAI/2017 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | ||||||||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=29929&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=29929&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.29929 | ||||||||||||
Resumo: | |||||||||||||
Porous heterogeneous media subjected to chemical etching in high temperature conditions represent a segment of outstanding importance in the scientific and industrial field. The diffusants effective penetration profile in porous media is a topic of broad significance and complexity in transport phenomena of
momentum, heat and mass; once it describes the concept of transient configurational diffusion phenomena in unsaturated zones and therefore, a mathematical approach to its formulation. The purpose of this study is the development of a numerical mathematical model for predicting the transient diffusion process of oxides diffusants in porous heterogeneous media. Thus, experimental transient diffusion tests were performed with solids diffusants composed of iron oxides (II), (II,III) and (III) in porous silico-aluminous refractory media of high alumina (SiO2 Al2O3) with and without dopants of oxide chromium (III). A non-destructive computerized microtomography technique with digital 3D reconstruction and post-processing images was used for spatial monitoring each solid diffusant particle in the media. The influence of temperature was examined ranging from 1100 Celsius degrees to 1300 Celsius degrees, at exposure time of 100h, as well as the presence of dopants in the structure of porous media to mitigate penetration. Data of the normalized diffusants concentration field as function of the penetration depth were predicted by mass transfer transient models based on semi-infinite slabs formulation considering saturated boundary conditions. The
numerical results of mass transfer obtained by microtomography images processing were compared and correlated with the chemical surface mapping method with EDS scan for elementary microanalysis. From the experimental and simulated data was quantified the porous media diffusivity. It was observed a variation less than 3.52 percent between destructive and non-destructive methods analyzed to quantify the normalized diffusants concentration along the media depth, enhancing the proposed method to be extended to other porous media and solids diffusants.
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