粒状物料常压吸附流化床冷冻干燥的传热研究

STUDY ON HEAT TRANSFER OF ADSORPTION FLUIDIZED BED FREEZE-DRYING OF GRANULAR MATERIAL AT ATMOSPHERIC PRESSURE

以粒状马铃薯为研究对象，在常压吸附流化床冷冻干燥的实验基础上，建立了吸附流化床内对流边界条件下的球坐标冻干模型，并采用变时间步长的有限差分法，求解了物料内部温度分布及升华界面的移动速率，与实验结果吻合较好，分析了有关因素对于冻干过程中传热及干燥过程的影响。

Granular potato is selected as experimental material in this paper. On the basis of atmospheric pressure adsorption fluidized bed freeze drying experimental research, an unsteady math- ematical model of this kind of freeze-drying process at atmospheric pressure is established in spherical geometry with convection boundary condition. Variable time step finite-difference method is introduced in order to gain the changing curves of the temperature distribution and sublimating ice interface. The changing of temperature and drying rate are measured in the experiments. The calculated results are proved in comparison with experimental data. Influences of related factors on the heat transfer and freeze-drying process are analyzed.