Resumo

GASTON, A. L.; ABALONE, R. M.; GINER, S. A.  e  BRUCE, D. M.. Geometry effect on water diffusivity estimation in PROINTA-Isla Verde and broom wheat cultivars. Lat. Am. appl. res. [online]. 2003, vol.33, n.3, pp.327-331. ISSN 0327-0793.

The effect of geometry representation of the grain kernel in the estimation of the effective diffusion coefficient of water in wheat, cv. Broom, is studied. Isothermal thin layer drying is assumed. The two-dimensional diffusive mass transport equation is solved for spherical and ellipsoidal geometries. The effective diffusion coefficient was estimated for drying air temperatures of 64, 70 and 75^oC and initial grain moistures of 0.22, 0.25 and 0.28 db. Results were correlated by means of Arrhenius-type functions, varying from 2.953x10^-11 to 6.687x10^-11 m²/s for ellipsoidal geometry and from 3.336x10^-11 to 7.772x10^-11 m²/s for spheres. An average ratio of diffusion coefficients for ellipsoid to those for spheres was calculated to be about 0.85, very close to the value of 0.86 obtained in a previous work for the "PROINTA-Isla Verde" wheat cultivar. This ratio can be considered to be equal to the wheat sphericity squared.

Palavras-chave : Wheat; Thin Layer Drying; Diffusivity Estimation.

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