茶叶烘干机干燥数学模型的建立 Ⅱ.茶叶烘干机多薄层干燥模型

Mathematical Model of Drying for Tea Dryer Ⅱ.A Multi-layer Drying Model for Tea Dryer

把绿茶揉捻叶在链板式茶叶烘干机内的干燥过程视作一个多薄层的干燥过程,并依据薄层叠代计算的原理,建立了茶叶烘干机多薄层干燥数学模型,在进叶叶层厚度为3—4厘米、进风温度为85—120℃和链轮转速为3—7转/分钟的干燥条件下,出叶含水率的模型预测值与实测值之间的绝对差均值为1.49(%,湿基),烘干机干燥过程含水率变化的模型预测值与实测值之间的均方差小于0.03145。

Based on the experimental data of thin layer drying model obtained fromthe oven of tea dryer and after treating the data with the continuous iterat-ive computation method,the authors built up a multi-layer drying model tosimulate the moisture content histories of rolled tea leaves in a tea dryer(6CH-20A)with a large amount of hot air.The predicted value of moisturecontent fitted in well with that of experiment.The drying rates for rolledleaves in primary drying process in a dryer depended on drying air tempera-ture,initial moisture content and the thickness of the leaf layer.The dryingrate increased with the decreasing of the leaf layer thickness,and with theincreasings of initial moisture content and drying air temperature.Both thepredicted and experimental moisture content histories were presented in theform of same chart for comparing,and the mean square deviation was0.03145.The absolute error between the predicted and experimental valuesof the out leaves was smaller than 1.5%(w.b.).