Aplicação de modelo matemático fenomenológico para análise e simulação do congelamento de fishburguer

Abstract

The objective of this work was to carry out a theoretical study and to evaluate mathematical models, using computer codes in Maple®16 language that simulate the freezing process of tilapia’s fishburger. Experimentals were conducted in a conventional freezer with fast freezing function (H500, Eletrolux). Parameters were obtained from the freezing curves such as freezing speed (8.33 10-7 m s-1), freezing air temperature inside the freezer (-30 °C) and temperature in the center of the fishburger measured by T-type thermocouples (Novus). The mathematical model evaluated was of distributed parameters, considering the fishburger as a physical system that exchanges heat by conduction and natural convection with its surroundings, uniform cooling and one-dimensional heat transfer. The thermophysical properties were estimated from empirical equations that consider the product composition. The numerical method selected for solving the mathematical model was the method of lines. After determining the thermophysical properties and solving the equations, it was possible to simulate the temperature behavior as a function of time in the freezing process of tilapia’s fishburger. The simulation that presented the highest correlation coefficient (0.92) between the experimental and the simulated curve was obtained using the thermal conductivity as a function of temperature and a convective coefficient of 12.6 W m-2 K-1. These results showed that the proposed mathematical model fitted the experimental data, therefore, the proposed model simulated the freezing profile of the tilapia’s fishburger.