中文摘要：

为提高过程的经济性,提出了液体物料初始非饱和冷冻干燥的技术思想．推导了冷冻干燥质、热耦合传递模型,模型采用了新的吸附-解吸平衡关系,并考虑了吸湿效应．控制方程用有限容积法进行数值求解．待干水溶液中的溶质选用典型的药物赋形剂——甘露醇．结果表明,初始非饱和多孔物料能够显著减少干燥时间,达到强化冷冻干燥的目的．随初始孔隙率 ε_0（1-S_0） 的不断增大,干燥时间逐渐缩短；在物料初始饱和度 S_0为0.30~0.35时,干燥时间达到最短．依据干燥过程中饱和度和温度的分布,分析了物料内部质、热传递机理和干燥速率控制因素．对有效质量扩散系数 K_S 和有效导热系数 λ＋K_T ΔH 的分析显示,随着冷冻干燥的进行,物料瞬时孔隙率 ε_0（1-S） 不断增大,过程将由传质控制逐渐变为传热控制．

英文摘要：

To improve the process economy ,freeze-drying of initially unsaturated frozen material from aqueous solution is put forward in the present investigation .A novel heat and mass transfer model of freeze-drying with hygroscopic effect was derived on the basis of a new adsorption-desorption relationship .The finite-volume method was adopted in solving the governing equations .Mannitol ,a typical pharmaceutical excipient , was selected as the solute in aqueous solution to be dried . Experimental results show that the freeze-drying process can be enhanced indeed using the initially unsaturated frozen material ,and drying time decreases with increase in the initial porosity ,ε0 （1 -S0 ） .There is the shortest drying time in correspondence with about 0 .30-0 .35 of initial saturation , S0 .According to the profiles of temperature and saturation ,heat and mass transfer mechanism was discussed and the drying rate-controlling factor was analyzed . Inspection on the effective mass diffusivity ,KS and the effective heat conductivity ,λ＋ KTΔH displays that the rate-controlling factor would change from mass transfer to heat transfer with increase in instantaneous porosity ,ε0 （1-S） .