EFFECTS OF HIGH-FREQUENCY ELECTROMAGNETIC-FIELD ON HEAT-SENSITIVE MEDIA .2. DRYING KINETICS AND SIMULATION

Drying of heat sensitive materials may be performed with the use of coupled microwave and convective energy input. Drying kinetics have been studied in a closed cycle drying tunnel at different ratios of microwave and convective energies for gelatin film and polyacrylamide sphere. Four zones of drying curves can be distinguished. Continuous microwave energy input results in overpressure period, a '' hump'' in the drying curve. Overheating may be avoided by automatic control of the drying process. A uniform temperature distribution has been considered within the material for simulation of drying process. Simulation was performed with the enthalpy balance, the isothermal and non-isothermal models, respectively.