Influence of the geometry on the numerical simulation of the cooling kinetics of cucumbers

W. P. Silva, C. M. D. P. S. Silva, P. L. Nascimento, J. E. F. Carmo, D. D. P. S. Silva

Abstract


In this paper, the effect of the geometric representation of cucumbers on the numerical simulation of its cooling kinetics is studied. It is supposed that the diffusion model with boundary condition of the third kind satisfactorily describes the cooling, and that the thermo-physical parameters are constant during the process. The geometries used to represent the cucumber are: infinite cylinder, finite cylinder, and ellipsoid. The diffusion equation was solved through the finite volume method, with a fully implicit formulation, using cylindrical and generalized coordinates. The convective heat transfer coefficient and the thermal diffusivity were determined through optimization, using the inverse method. The best model in the representation of the cucumber’s shape was the ellipsoid, but the time demanded in its optimization was about 66 times greater than the time for the infinite cylinder.


Keywords


convective heat transfer coefficient; Cucumis sativus; cylindrical coordinates; diffusion; finite volume method; generalized coordinates; thermal diffusivity

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References


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DOI: 10.5424/sjar/20110901-055-10