Semi-Empirical Model of Convective Drying with Wide Range Layer Depth Validity

Abstract

While the theoretical models with distributing parameters serve a lot of professional-scientific information about various process details but the empirical simulations use black-box models, in general, in several cases on the basis of classical heat- and mass transfer equations. All the parameters of a real simulation can not be given, e.g., in cases of biological materials in batches have no homogeneous inner structures and diffusion factors, thus they can be approximated only by using functions with many vaiables. Using empirical data as in the case of Newton's Cooling law a half-empirical approach can be applied to the dewatering process, which comes close to the aims of practical drying. An experimental data based description of the drying process postulates the circumstances of practical drying. The global (or unified parameter) method ignores the detailed analysis of the drying zones and gives no information regarding the inner heat and moisture distribution. To obtain practical results, this method, however, is suitable for determining the technical parameters. As a result of our research on corn kernels, a half-empirical modeling method has been developed within the MATLAB environment.

Keywords:

• Activation time
• Mathematical modeling
• SIMULINK toolbox
• Variable bed height

ACKNOWLEDGEMENT

The authors are grateful to the OTKA foundation (T037420) for the financial support.

Notes

¹During half time, half of its removable moisture content evaporates from the dried materials.

²Δ is the number of layers for which the whole dried batch can be divided in order to carry out the simulation.