Air impingement drying characteristics and model of Chinese jujube

Abstract

Abstract. In this paper air impingement drying technology was applied to drying Chinese jujube. The drying characteristics, moisture effective diffusivity and the activation energy of Chinese jujube drying were investigated under different air temperatures (55, 60, 65 and 70 °) and air velocities (6, 9, 12 and 15 m/s). The mathematical model of air impingement drying Chinese jujube was obtained. The Fick’s second law of diffusion was used to calculate the moisture effective diffusivity, which increased from 5.38958A—10 -10 to 12.34222A—10 -10 m 2 /s with the increasing the air temperature and air velocity. The activation energy was 51.8 kJ/mol, which was determined from Arrhenius equation. According to the statistical parameters as the correlation coefficient(R 2 ), root mean square error(RMSE) and I‡ 2 , the Logarithmic model was the best suitable to descript the relationship of Chinese jujube moisture and drying time by air impingement drying. This research provides technical basis for industrial drying of Chinese jujube using the air impingement drying technology.