Numerical Modeling of the Process of Drying Biomaterials After Pulsed Electric Field Treatment Using a System of Tempera
- PDF / 1,209,248 Bytes
- 11 Pages / 594 x 792 pts Page_size
- 91 Downloads / 174 Views
Journal of Engineering Physics and Thermophysics, Vol. 93, No. 5, September, 2020
NUMERICAL MODELING OF THE PROCESS OF DRYING BIOMATERIALS AFTER PULSED ELECTRIC FIELD TREATMENT USING A SYSTEM OF TEMPERATURE, MOISTURE, AND PRESSURE EQUATIONS I. A. Shorstkii, V. S. Kosachev, and E. P. Koshevoi
UDC 66.086.2:519.61
A new method is described to determine the kinetic coefficients for temperature, moisture, and pressure potentials based on experimental data of a curve for drying capillary-porous bodies. This method includes numerical modeling of the problem of calculating the potential of transfer of temperature, moisture, and pressure in the process of drying based on the procedure of using the finite element method in combination with the stepwise method of finite differences for a partial differential system, and an inverse problem formulation in the form of minimizing the residual function square from the obtained experimental curve of the moisture potential. Based on this method, the updated coefficients of kinetic potentials were found for many materials after pulsed electric field treatment and dependence curves were restored for temperature and pressure potentials that were not observed in the experiment. The presented approach is quite useful for the study of the mechanism of a drying process with pulsed electric field pretreatment, and for the explanation of the occurring effects, and the updated kinetic coefficients based on experimental data contribute to the substantiation of the processes occurring in the object of drying. Keywords: kinetic coefficient, inverse problem, heat and mass transfer, drying, potential, numerical modeling, pulsed electric field. Introduction. In terms of the thermodynamics of the process, the occurring intense mass transfer in materials pretreated with a pulsed electric field (PEF) is caused by the formation of a great number of micropores located in a spontaneous and random pattern on the surface of the biomaterial along the electric-field lines of force [1]. Pulsed electric field pretreatment can have a positive effect on the dynamics of mass transfer in biomaterials due to a change in volume porosity [2, 3], the presence of a released liquid phase on the surface of the material at the initial instant of time [4], the increase in total diffusion, and, as a consequence, the change of certain thermodynamic parameters of the drying object itself (heat capacity, thermal conductivity, etc.). Knowledge of the mechanism of heat and mass transfer in the process of drying for a biomaterial pretreated with an electrophysical field is necessary in constructing the fundamentals for the development of advanced technologies in food, chemical, and other industries. In recent years, the scientific community has reached a consensus regarding the fact that the process of drying is simultaneously the process of transfer of heat, free moisture, bound moisture, moisture in the vapor state, and air, and that a full description of the process of drying requires the use of nonlinear partial differenti
Data Loading...
