食品冻干中的热质传递特性与最佳升华压力

The Transport Properties and the Optimal Chamber Pressure in Food Freeze Drying

通常情况下,食品冷冻干燥中的升华速率受物料已干层内的热量传递过程控制,冻干室压力可较大程度地影响通过物料已干层的传热速率。本文建立了辐射给热条件下食品冷冻干燥过程的数学模型,并在物料热质传递特性随压力变化关系的基础上,用数值法计算出了物料的最佳升华压力,实验证明、计算值与实验值相吻合。

Freeze drying of foodstuffs is ordinarily controlled by the heat conduction through the dried layer which is affected by the chamber pressure. A mathematical model of freeze drying with radiation condition was proposed in this paper and the optimal chamber pressure was calculated based on the relationship between transport properties and pressure. The predicted results were in good agreement with experimental values.