Description of Whole Banana Drying through a Diffusion Model Using Numerical Solution via Generalized Coordinates

Abstract:

Drying is a method of preservation widely used to prolong the post-harvest life of several agricultural products. In this work, experiments were accomplished involving drying of whole bananas, using hot air at temperature of 40.0 ^ºC and constant velocity of 1.5 m s^-1. The mass loss in regular time intervals was measured using the gravimetric method. In order to describe the process, the liquid diffusion model was used, assuming variable volume and effective mass diffusivity [. Thus, the diffusion equation was numerically solved through the finite volume method, with a fully implicit formulation. Due to the geometry of the product, the diffusion equation was written in generalized coordinates, and then discretized, assuming boundary condition of the third kind [. To take advantage of the symmetry, bananas were considered as revolution solids, obtained by the rotation of an area in the plane (x,y) about the axis y. The area was obtained directly of the photography of a banana, which served to create a non-orthogonal structured grid with 32 x 40 control volumes. The thermo-physical parameters were obtained through an optimization algorithm, based on the inverse method. Once the thermo-physical parameters were known, the drying kinetics as well as the water distribution within the bananas in stipulated times were presented and analyzed. The statistical indicators enable to conclude the methodology proposed to describe whole banana drying presents good results.

• Periodical: Defect and Diffusion Forum (Volumes 334-335)
• Pages: 143-148
• DOI: https://doi.org/10.4028/www.scientific.net/DDF.334-335.143
• Online since: February 2013
• Authors: C.M.D.P. Silva e Silva, Wilton Pereira Silva, J.P. Gomes, V.S.O. Farias, L.D. Silva, F.J.A. Gama
• Keywords: Banana, Diffusion, Drying Kinetics, Generalized Coordinates

References

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DOI: 10.21475/ajcs.18.12.05.pne925

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DOI: 10.21475/ajcs.2016.10.10.p7455

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[9] W.P. Silva: PhD Thesis. Process Engineering, Center of Science and Technology, Federal University of Campina Grande, Campina Grande-PB, Brazil (2007).

DOI: 10.21475/ajcs.18.12.05.pne925

[10] V.S.O. Farias: PhD Thesis. Process Engineering, Center of Science and Technology, Federal University of Campina Grande, Campina Grande-PB, Brazil (2011).

DOI: 10.21475/ajcs.2016.10.10.p7455

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