番木瓜片的热风干燥特性与动力学模型

Hot-air Drying Characteristics and Kinetics Model of Papaya Slices

以热风温度、风速、装载量和切片厚度为试验因素,研究不同条件下番木瓜片热风干燥的干燥时间曲线和干燥速率曲线,确定干燥最佳工艺参数组合,并建立热风干燥动力学模型。结果表明:番木瓜热风干燥过程同时受到热风温度、热风风速和切片厚度等条件的影响,装载量的大小对番木瓜片失水和干燥速率的影响并不显著。整个热风干燥过程只有降速干燥阶段,无明显的加速和恒速干燥阶段,干燥速率呈下降趋势。切片厚度对干燥速率影响极大,番木瓜片切片厚度4 mm的干燥时间比厚度8 mm的干燥时间缩短了近50%。番木瓜片热风干燥的动力学模型满足Page方程MR=exp(-rt^n),能较好地描述和预测番木瓜片热风干燥过程水分的变化。

The drying time curve and drying rate curve of hot-air drying of papaya slices under different conditions were studied by using hot-air temperature, air velocity, thickness and loading capacity as the experimental factors.The optimum drying process parameters were determined and the hot-air drying kinetics model was established.The results showed that the hot air drying process was affected by hot air temperature, air velocity and thickness,and the affect of loading capacity was not obvious. It had only falling rate stage and drying rate of decline, without increasing rate and constant rate stages, the thickness had a great influence on the drying rate. The drying time for papaya slices 4 mm thick was shortened by nearly 50% over that of the slices 8 mm thick. The Page equation MR=exp（-rtn） could accurately describe the hot air drying process of papaya slices, and it could describe and predict the change of moisture in the hot air drying process of papaya slices.