Modelagem do processo da secagem de produtos agrícolas: formulacão de Luikov considerando parâmetros termofísicos variáveis e uso da GITT

• Ano de defesa: 2017
• Autor(a) principal: Lajaña, Mauricio Andres Gaggero
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Engenharia de Energias Renováveis; Programa de Pós-Graduação em Energias Renováveis; UFPB
• Palavras-chave em Português: Secagem Solar; Luikov; GITT; Solar drying; CNPQ::ENGENHARIAS
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/12770

Agricultural products drying is one of the ?rst techniques used by mankind in order to preserve food without compromising its nutritional value, taste, texture, etc. Along time, there have been some sophistications in the process, but itˆas essential principles remain the same. Drying consists in extracting the humidity of a certain product, which is done by a combination of ventilation and heat exposure. The physical phenomena involved in the drying process are heat and mass transfer, which manifest themselves through the mechanisms of conduction and convection, and di?ussion and evaporation, respectively. In this research, Luikov’s model was used because it considers heat and mass transfer as a coupled problem, in opposition to other models in which they are considered to be isolated problems. In Luikov’s model, thermophisical parameters are de?ned, related to the dimensionless numbers Lu, Biq and Bim, and they must be carefully chosen in order to obtain acceptable results (similar to experimental results). One option can be choosing these parameters as constants, obtaining Luikov’s linear system of equations. Nevertheless, in this research, the thermophysical parameters were chosen as fuctions of time. The result is a nor-linear system of equations, which is more di?cult to solve. For solving the equtions, the General Integral Transform Tecnique (GITT) was used. It is an hybrid analytical-numerical method, which de?nition depends strongly on the initial and border conditions. Six cases were analized, de?ning Lu, Biq and Bim as linear increasing and decreasing time functions. In general terms, the results were the expected ones: when Lu decreases, temperature increases with a higher rate and humidity decreases with a lower rate; when Biq increases, temperature increases with a lower rate and humidity decreases with the same rate; and when Bim increases, temperature increases with a lower rate and humidity decreases with a higher rate. It can be concluded that the model depends strongly on these parameters, making interesting further experimental research.