Transmission line modelling (TLM) of water diffusion in white rice

doi:10.1016/0260-8774(86)90003-8

Journal of Food Engineering

Volume 5, Issue 4, 1986, Pages 269-285

https://doi.org/10.1016/0260-8774(86)90003-8 Get rights and content

Abstract

The use of TLM to describe the soaking behaviour of white rice is demonstrated. A TLM grid with constant mesh size was built up for white rice, and results of calculations (for a known diffusion coefficient) were compared with the finite element technique. In a further step the diffusion coefficient for white rice soaking was calculated by means of the TLM model as a function of temperature. The average mass diffusivities were calculated to be 1·69, 1·97 and 2·28 × 10⁻¹⁰m²s⁻¹ at temperatures of 30, 40 and 50°C. The model adequately described the experimental data. On the basis of an Arrhenius-type equation the activation energy for water diffusion in white rice was calculated as 11·3 kJ mol⁻¹ (for the same temperature range).

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Axisymmetric TLM model for water vapor soaking of white rice
1987, Journal of Food Engineering
An earlier-developed, two-dimensional, orthogonal TLM grid, using axisymmetric elements, has been used to model moisture diffusion during long-grain white rice soaking in moist still air. Previously, soaking of rice in water was shown to depend largely on the diffusion properties of moisture inside the kernel. However, in the case of water vapor soaking, the experimental soaking curves can only be approximated very closely by assuming a surface resistance. Further, this analysis shows that the resistance to moisture transfer to the surface, which is represented by a mass-transfer coefficient, is the controlling factor. As a consequence of this resistance at the surface, which dominates the internal resistance to moisture diffusion, almost no concentration gradients occur inside the kernel. Finally, using an Arrhenius-type equation, an exponential relationship between the mass-transfer coefficient and the inverse of the absolute temperature was found.
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View full text

Transmission line modelling (TLM) of water diffusion in white rice

Abstract

J. Food Technol.

Drying kinetics of rough rice grain

J. Food Technol.

Cereal foods

Kinetics of water diffusion and starch gelatinisation during rice parboiling

J. Food Sci.

A semi-empirical correlation for prediction of hydration characteristics of paddy during parboiling

J. Food Technol.

Desorption characteristics of hot soaked parboiled paddy

J. Food Technol.

A study of internal moisture movement in the drying of the wheat kernel

Cereal Chemistry

On the application of transmission line modelling to diffusion

The solution of moving boundary heat problems using the TLM method of numerical analysis

A study of diffusion equation describing moisture movement in peanut pods — I: comparison of vapor and liquid diffusion equations

Trans. ASAE

A study of diffusion equations describing moisture movement in peanut pods — II: simultaneous vapor and liquid diffusion of moisture

Trans. ASAE

A study of diffusion equations describing moisture movement in peanut pods — II: simultaneous vapor and liquid diffusion of moisture

Trans. ASAE

Diffusional processes in the drying of tapioca root

J. Food Sci.