Please use this identifier to cite or link to this item: http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/10549
Title: Estudo do processo de secagem de blocos cerâmicos estruturais: modelagem e simulação.
Other Titles: Study of the drying process of structural ceramic blocks: modeling and simulation.
???metadata.dc.creator???: SANTOS, Rosilda Sousa.
???metadata.dc.contributor.advisor1???: FARIAS NETO, Severino Rodrigues de.
???metadata.dc.contributor.advisor2???: LIMA, Antonio Gilson Barbosa de.
???metadata.dc.contributor.referee1???: FARIAS, Fabiana Pimentel Macêdo.
???metadata.dc.contributor.referee2???: GOMES, Josivanda Palmeira.
???metadata.dc.contributor.referee3???: VIEIRA, Fernando Fernandes.
???metadata.dc.contributor.referee4???: LEITE, Boniek Evangelista.
Keywords: Secagem em Estufa;Tijolo Estrutural;Transferência de Calor e Massa,;Modelo Difusão Líquida;CFD;Greenhouse Drying;Heat and Mass Transfer;Liquid Diffusion Model;Structural Brick
Issue Date: 25-Apr-2019
Publisher: Universidade Federal de Campina Grande
Citation: SANTOS, R. S. Estudo do processo de secagem de blocos cerâmicos estruturais: modelagem e simulação. 2019. 214 f. Tese (Doutorado em Engenharia de Processos) – Programa de Pós-Graduação em Engenharia de Processos, Centro de Ciência e Tecnologia, Universidade Federal de Campina Grande, Paraíba, Brasil, 2019.
???metadata.dc.description.resumo???: Diversos estudos sobre a secagem de materiais cerâmicos vêm sendo desenvolvidos nos diversos setores da engenharia e fabricação. Tendo em vista que, este processo de secagem, porém, demanda grandes investimentos e alto consumo de energia, elevando os custos deste setor. Em muitas situações, é comum o uso de soluções teóricas como simulações numéricas que permitem, com relativa facilidade e baixo custo, alterar as condições operacionais e geométricas do secador ou objeto de secagem. Neste sentido, este trabalho foi realizado com o objetivo de estudar o processo de secagem de tijolos cerâmicos estruturais compensadores industriais, considerando como um meio sólido, via Fluidodinâmica Computacional (CFD), nas seguintes condições experimentais: temperatura de secagem de 50 °C e 100°C, teor de umidade inicial de 0,1723191 e 0,169366 (kg/kg, b.s.) e umidade relativa do ar 18,39% e 2,34%, respectivamente. Foi realizado um estudo de malha utilizando o método do Índice de Convergência de Malha (ICM). Adotou-se um modelo matemático tridimensional transiente com base nas equações de conservação de massa, momento e energia, para descrever as trocas de calor e massa durante o processo de secagem. O fenômeno de secagem do tijolo estrutural foi estudado em duas situações: a primeira a secagem de tijolo compensador isoladamente considerando o modelo de secagem por difusão líquida. A segunda situação, onde o domínio de estudo considera o tijolo em uma estufa, neste caso realizando o acoplamento dos modelos de difusão líquida para o tijolo e de convecção forçada no lado da estufa. Foram analisados os resultados do campo de pressão, velocidade, temperatura e fração volumétrica da água no interior do tijolo obtido pelo pacote comercial Ansys CFX® 15.0. A comparação entre o teor de umidade e temperatura simulados com os dados experimentais permitiu validar os resultados numéricos e, assim, estimar os coeficientes de difusão de massa e transferência de calor na superfície do material. Os resultados das simulações indicam que há regiões com importantes gradientes de temperatura e umidade o que podem conduzir a ocorrência de trincas e deformações. Palavras – chave: Secagem em estufa, tijolo estrutural, transferência de calor e massa, modelo difusão líquida, CFD. viii ROSILDA, S. S., “Study of the drying process of structural ceramic blocks: modeling and simulation”. 2019. 216f. Tese (Doutorado em Engenharia de Processos), Universidade Federal de Campina Grande, Campina Grande, 2019. ABSTRACT Several studies on the drying of ceramic materials have been developed in various engineering and manufacturing sectors. Considering that, this drying process, however, requires large investments and high energy consumption, raising the costs of this sector. In many situations, it is common to use theoretical solutions such as numerical simulations that allow, with relative ease and low cost, to change the operational and geometric conditions of the dryer or object of drying. In this sense, this work was carried out with the objective of studying the drying process of industrial ceramic structural bricks, considering as a solid medium, via Computational Fluid Dynamics (CFD), under the following experimental conditions: drying temperature of 50 °C and 100 °C , initial moisture content of 0,11723191 and 0,169366 (kg/kg, b.s) and relative humidity 18,39% and 2,34%, respectively. A mesh study was performed using the Grid Convergence Index (GCI) method. A transient three-dimensional mathematical model was adopted based on the conservation equations of mass, moment and energy, to describe the heat and mass changes during the drying process. The drying phenomenon of the structural brick was studied in two situations: the first the drying of compensating brick alone considering the model of drying by liquid diffusion. The second situation, where the domain of study considers the brick in a greenhouse, in this case making the coupling of the models of liquid diffusion to the brick and forced convection on the side of the greenhouse. The results of the field of pressure, velocity, temperature and volume fraction of the water inside the brick obtained by the commercial package Ansys CFX® 15.0 were analyzed. Comparison between the simulated moisture and temperature content with the experimental data allowed us to validate the numerical results and, thus, to estimate the mass diffusion and heat transfer coefficients on the surface of the material. The results of the simulations indicate that there are regions with important temperature and humidity gradients which can lead to cracks and deformations.
Abstract: Several studies on the drying of ceramic materials have been developed in various engineering and manufacturing sectors. Considering that, this drying process, however, requires large investments and high energy consumption, raising the costs of this sector. In many situations, it is common to use theoretical solutions such as numerical simulations that allow, with relative ease and low cost, to change the operational and geometric conditions of the dryer or object of drying. In this sense, this work was carried out with the objective of studying the drying process of industrial ceramic structural bricks, considering as a solid medium, via Computational Fluid Dynamics (CFD), under the following experimental conditions: drying temperature of 50 °C and 100 °C , initial moisture content of 0,11723191 and 0,169366 (kg/kg, b.s) and relative humidity 18,39% and 2,34%, respectively. A mesh study was performed using the Grid Convergence Index (GCI) method. A transient three-dimensional mathematical model was adopted based on the conservation equations of mass, moment and energy, to describe the heat and mass changes during the drying process. The drying phenomenon of the structural brick was studied in two situations: the first the drying of compensating brick alone considering the model of drying by liquid diffusion. The second situation, where the domain of study considers the brick in a greenhouse, in this case making the coupling of the models of liquid diffusion to the brick and forced convection on the side of the greenhouse. The results of the field of pressure, velocity, temperature and volume fraction of the water inside the brick obtained by the commercial package Ansys CFX® 15.0 were analyzed. Comparison between the simulated moisture and temperature content with the experimental data allowed us to validate the numerical results and, thus, to estimate the mass diffusion and heat transfer coefficients on the surface of the material. The results of the simulations indicate that there are regions with important temperature and humidity gradients which can lead to cracks and deformations. ..
Keywords: Secagem em Estufa
Tijolo Estrutural
Transferência de Calor e Massa,
Modelo Difusão Líquida
CFD
Greenhouse Drying
Heat and Mass Transfer
Liquid Diffusion Model
Structural Brick
???metadata.dc.subject.cnpq???: Engenharias.
URI: http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/10549
Appears in Collections:Doutorado em Engenharia de Processos.

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