Avaliação da sudação externa em um refrigerador
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Data
2022-07-29
Autores
Muniz, Pedro Afonso Mastrogiacomo
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
No passado, devido à inadequada forma de conservação dos alimentos, o estudo na área de refrigeração tem sido cada vez mais crescente no mundo. Assim, abordagens empíricas, teóricas e até a utilização de recursos computacionais, têm sido utilizadas para o desenvolvimento de refrigeradores, devido à grande importância para a conservação de alimentos e bebidas. Porém, como qualquer tecnologia existente,
refrigeradores podem apresentar defeitos e problemas que acabam sendo inconvenientes para o consumidor. Entre os principais problemas, a sudação se destaca. Refrigeradores comerciais acabam “suando”, ou seja, ocorre o processo de condensação de água sobre as paredes externas, provocando o acúmulo de condensado próximo aos equipamentos. Desta forma, a partir da modelagem computacional no software ANSYS, foi modelado uma geometria representativa e simplificada de um refrigerador comercial para o estudo da sudação externa. Foram utilizadas condições de contorno específicas de operação, como a temperatura ambiente de 20 °𝐶������� e parede fria interna do refrigerador em −10 °𝐶������� e −20°𝐶�������, considerando a transferência de calor interna por convecção natural em regime transitório. Dados
psicrométricos também foram aplicados a partir dos resultados das simulações numéricas para o cálculo do ponto de orvalho nas superfícies das paredes externas do refrigerador. Por fim, com base nos resultados das velocidades da cavidade interna e da temperatura das paredes externas, verificou-se a presença do fenômeno de condensação do ar na superfície das paredes externas.
In the past, due to the inadequate way of preserving food, the study in the area of refrigeration has been increasing in the world. Thus, empirical and theoretical approaches, and even the use of computational resources, have been used for the development of refrigerators, due to their great importance for the conservation of food and beverages. However, like any existing technology, refrigerators can have defects and problems that end up being inconvenient for the consumer. Among the main problems, sweating stands out. Commercial refrigerators end up “sweating”, that is, the process of water condensation occurs on the external walls, causing the accumulation of condensate near the equipment. Thus, from the computational modeling in the ANSYS software, a representative and simplified geometry of a commercial refrigerator was modeled for the study of external sweating. Specific operating boundary conditions were used, such as ambient temperature of 20 °C and internal cold wall of the refrigerator at -10 °C and -20 °C, considering the internal heat transfer by natural convection in a transient regime. Psychrometric data were also applied from the results of numerical simulations to calculate the dew point on the surfaces of the external walls of the refrigerator. Finally, based on the results of the velocities of the internal cavity and the temperature of the external walls of the two numerical analyses, the presence of the phenomenon of air condensation on the surface of the external walls was verified.
In the past, due to the inadequate way of preserving food, the study in the area of refrigeration has been increasing in the world. Thus, empirical and theoretical approaches, and even the use of computational resources, have been used for the development of refrigerators, due to their great importance for the conservation of food and beverages. However, like any existing technology, refrigerators can have defects and problems that end up being inconvenient for the consumer. Among the main problems, sweating stands out. Commercial refrigerators end up “sweating”, that is, the process of water condensation occurs on the external walls, causing the accumulation of condensate near the equipment. Thus, from the computational modeling in the ANSYS software, a representative and simplified geometry of a commercial refrigerator was modeled for the study of external sweating. Specific operating boundary conditions were used, such as ambient temperature of 20 °C and internal cold wall of the refrigerator at -10 °C and -20 °C, considering the internal heat transfer by natural convection in a transient regime. Psychrometric data were also applied from the results of numerical simulations to calculate the dew point on the surfaces of the external walls of the refrigerator. Finally, based on the results of the velocities of the internal cavity and the temperature of the external walls of the two numerical analyses, the presence of the phenomenon of air condensation on the surface of the external walls was verified.
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Palavras-chave
Psicrometria, Sudação, Simulação numérica, Psychrometry, Sweating, Computer simulation