| 1st Nordic Drying Conference - NDC'01, Trondheim, Norway, June 27-29, 2001 | |
DRYING OF MANGO IN A HEAT PUMP DRYER: DRYING KINETICS AND SHRINKAGEXiang Hui1, M.S. Uddin2 and M.N.A. Hawlader31,2 Chemical and Environmental Engineering Department 3 Mechanical Engineering Department, National University of Singapore 10 Kent Ridge Crescent, Singapore 119260 1 E-mail: engp9325@nus.edu.sg 2 E-mail: cheshahb@nus.edu.sg 3 E-mail: mpehawla@nus.edu.sg Keywords: mango, heat pump, drying kinetics, shrinkage, effective diffusivity ABSTRACT A heat pump dryer, which enables drying under low temperature conditions, has been used to dry mango to achieve a better understanding of the drying kinetics and shrinkage of the materials, when subjected to different operating conditions. The results show that there is no constant drying rate period and drying rate depends on parameters such as air temperature, air velocity and sample thickness. Sample shrinkage, both volumetric and thickness, has been measured and correlated to moisture content. Volumetric shrinkage is correlated to moisture content as a linear function, whereas, shrinkage based on thickness follows an exponential function. Fick's second law of diffusion is used to calculate the effective diffusivity.
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