Dynamics of convective hot air drying of filiform Lagenaria siceraria

Abstract

In this study, a laboratory convective hot air dryer was used for the thin-layer drying of filiform Lagenaria siceraria and the influences of the drying temperature and air velocity on the drying process were investigated. The drying temperature and the air velocity were varied in the range of 60-80?C and 0.6-1.04 m?s-1, respectively. The experimental data of moisture ratio of filiform Lagenaria siceraria were used to fit the mathematical models, and the dynamics parameters such as convective heat transfer coefficient ? and mass transfer coefficient kH were calculated. The results showed that the drying temperature and air velocity influenced the drying process significantly. The Logarithmic model showed the best fit to experimental drying data. It was also found that, the air velocity and the drying temperature influence notable on both of the convective heat transfer coefficient ? and the mass transfer coefficient kH. With the increase of hot air velocity from 0.423 to 1.120 ms-1, the values of ? varied from 111.3 to 157.7 W?m-2?K-1, the values of kH varied from 13.12 to 18.58 g?m-2? s-1??H-1. With the increase of air temperature from 60 to 80?C, the values of ? varied between 150.2 and 156.9 W?m-2?K-1, the values of kH varied between 18.26 and 18.75 g?m-2?s-1??H-1.