Estudo analítico e numérico das propriedades termo-físicas durante o processo de transferência de calor em produtos de forma cilíndrica.

Abstract

For many foodstuffs, the process of heat transfer is essential to reach the condition human consumption. The present work aims to study the phenomenon of transient diffusion of heat in pasty foodstuffs contained in cylindrical containers. The study presents solutions for the diffusion equation with boundary condition of the first kind. Analytical tools were developed - optimizer coupled to the analytical solution - to describe the diffusion of heat into products with the forms mentioned. Analytical tools were validated using data obtained by numerical simulation for both the cylinder the infinite and finite. The tools developed minimize errors in calculating the thermal diffusivity for the simulated data are acceptable when the temperature sensor is placed in the innermost region of the cylinder. The results obtained for the thermal diffusivity of agar gel, tomato puree and cream custard are consistents with the results found in the literature for these products. The software finite cylinder first kind was developed, validated and applied to data of tomato puree, cream custard and agar gel for various positions within the finite and infinite cylinder filled with these foodstuffs. All results obtained by simulation and optimization had an excellent agreement with the experimental results. The numerical method is more efficient than the analytical description of the heat diffusion process in the products, due to their versatility that allows obtaining the solution of the diffusion equation considering the thermal diffusivity varies with local temperature.