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Mathematical Problems in Engineering
Volume 2015, Article ID 480752, 15 pages
Research Article

Drying Characteristics and Model of Chinese Hawthorn Using Microwave Coupled with Hot Air

1College of Mechanical Science and Engineering, Jilin University, Changchun 130022, China
2College of Engineering, Heilongjiang Bayi Agricultural University, Daqing 163319, China
3College of Information Technology, Heilongjiang Bayi Agricultural University, Daqing 163319, China

Received 14 August 2014; Accepted 16 January 2015

Academic Editor: Oluwole Daniel Makinde

Copyright © 2015 Hai-Ming Yu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Microwave coupled with hot air drying kinetics and characteristics of hawthorn slices at different drying hot air temperatures, hot air velocities, and microwave power densities was investigated. The research results showed that drying occurred mainly in the falling rate period and in the accelerating period. Twelve mathematical models were selected to describe and compare the drying kinetics of hawthorn slices. By comparing three criterions including correlation coefficient, chi-square, and root mean square error, we determined that Weibull distribution model obtained the best fit and could best predict the experimental values. Consequently, Weibull distribution model could be used to aid dryer design and promote the efficiency of dryer operation by simulation and optimization of the drying processes. Moisture transfer from hawthorn slice was described by applying Fick’s second law and the effective diffusivity values were calculated by simplified Fick’s second law. The variable law of effective diffusivity values was consistent with the variable law of moisture ratio.