Abstract
The effects of microwave heating patterns were investigated for the case of batch fluidized bed drying by solving numerically a coupled heat and mass transfer model. Three patterns, uniform, sinusoidal and rectangular waves, were examined with the average electric field strength kept constant at 1000 V/m. Properties of apple were used to represent porous materials. The results show that the magnitude and distribution of the moisture, temperature and pressure within a particle can be significantly affected. More importantly, the drying time and microwave energy consumption change with the pattern of how microwave heating is applied. Particularly, intermittent heating with a rectangular wave pattern has the most microwave energy consumption but the shortest drying time. For a particle size of 5 mm, airflow rate of 2 m/s and temperature of 60°C, the bed area factor fAof 100, the drying time is, respectively, 1600, 2000, 2400 s for rectangular, sinusoidal, and constant microwave heating. The values of microwave energy consumed for the three cases are, respectively, 2145, 1980, and 1560 kJ/kg water evaporated.
Original language | English |
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Pages (from-to) | 6823-6835 |
Number of pages | 13 |
Journal | Chemical Engineering Science |
Volume | 56 |
Issue number | 24 |
DOIs | |
Publication status | Published - 14 Dec 2001 |
Externally published | Yes |
Keywords
- Apple
- Bed area factor
- Drying rate
- Energy consumption
- Moisture
ASJC Scopus subject areas
- General Chemistry
- General Chemical Engineering
- Industrial and Manufacturing Engineering