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论文类型：期刊论文

发表时间：2018-07-01

发表刊物：INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER

收录刊物：SCIE、EI

卷号：122

页面范围：1353-1365

ISSN号：0017-9310

关键字：Freeze-drying; Prebuilt porosity; Local mass non-equilibrium; Adsorption-desorption; Mass and heat transfer

摘要：A multiphase transport model based on the local mass non-equilibrium assumption was formulated to verify the effect of frozen material with prebuilt porosity on freeze-drying of liquids. An error function form of adsorption-desorption equilibrium relationship was proposed to describe the hygroscopic effect of moist porous media. Simulation results showed excellent agreements with the experimentally measured drying curves for initially saturated (S-0 = 1.00 or zero porosity) and unsaturated (S-0 = 0.28 or 0.69 of porosity) frozen materials. The unified equilibrium relation can be expressed as a polynomial form with a fixed parameter. Almost the same total radiation heat consumptions were attained for the initially saturated and unsaturated frozen samples. The initially prebuilt porosity with larger internal surface area of the unsaturated material can indeed decrease mass transfer resistance and increase energy efficiency of freeze-drying. Volumetric sublimation/desorption was achieved numerically in consistence with experimental findings through the analyses of saturation, temperature and mass source profiles. The mathematical model also provided satisfactory prediction capabilities of the ambient temperature effects on freeze-drying. (C) 2018 Elsevier Ltd. All rights reserved.