摘要
对振动流化床干燥过程中含有白蛋白的多孔混合颗粒的有效水分扩散系数进行了实验观察,建立了基于费克第二定律的数值模型。此模型可通过颗粒水分含量、体积孔隙率和温度预测有效水分扩散系数。结果表明,颗粒水分含量和孔隙结构特性对水分扩散系数有显著影响。在热力干燥过程中,特别是在干燥气流速度较高的情况下,一些生物材料的外部传质阻力很小以致水分传递只受物料内部的水分扩散控制,此时不应该忽略颗粒水分含量和孔隙结构对有效水分扩散系数的影响。
An investigation was undertaken of the moisture effective diffusivity from porous albumin containing paste particles in a vibrofluidized bed dryer and a mathematical model based on Fick＇s second diffusion equation was established to evaluate the effective diffusivity as a function of moisture content,bulk porosity and temperature.The results indicated that the influences of the particle moisture concentration and pore structure on the diffusivity are significant and they shouldn＇t been neglected during thermal drying of some biomaterials whose external resistance to mass transfer in general is small enough,especially when drying with high air velocity,to consider their moisture transport is governed by diffusion only.
基金
国家自然科学基金(51076163)
