超临界CO2干燥罗非鱼片的传质模型和数值模拟

为了探讨超临界CO2干燥罗非鱼的机理,该文基于微分床的质量守恒定律建立了超临界CO2干燥罗非鱼片的传质数学模型,通过Matlab软件对其干燥过程进行了数值模拟,分析了干燥室内超临界CO2中的溶质质量分数和罗非鱼片中的溶质质量分数随干燥时间和干燥床高度变化的规律,揭示溶质在超临界CO2干燥过程中的传质模式。结果表明:在超临界CO2干燥罗非鱼片的过程中,溶质传质主要以对流扩散为主,而以轴向扩散为辅;数值模拟的结果与试验值拟合良好(R2=0.97),相对偏差的绝对值在10%以内,说明建立的传质数学模型能较好的模拟超临界CO2干燥罗非鱼片的过程。研究结果可为超临界CO2干制罗非鱼片的工业化生产的过程控制提供参考。

Mass-transfer modeling and simulation of tilapia fillet drying by supercritical carbon dioxide

Supercritical carbon dioxide drying has been previously explored as an alternative to other techniques (e.g. air drying), which can retain the products original (micro) structure. It has been widely used in the production of inorganic and organic aerogels, for which preservation of the porous network during drying is essential to protect function. Drying by supercritical carbon dioxide just begins in the utilization of food processing. In order to probe into the mechanism of tilapia fillet drying by supercritical carbon dioxide, the conservation law of mass based on differential drying beds was used to establish the mass-transfer mathematic model of tilapia fillet drying by supercritical carbon dioxide. The model was simulated by software. It was analyzed that the content (mass fraction) of solute in supercritical carbon dioxide and in tilapia fillet changed with drying time and height of drying chamber. The mass-transfer model of solute in the process of drying by supercritical carbon dioxide was revealed. The results show that convective diffusion of solute was primary and axial diffusion was minor during the drying process of tilapia fillet by supercritical carbon dioxide. The results of numerical simulation with the experiment values were in good agreement (R2=0.97) and the absolute value of the relative deviation was less than 10%, which showed that the mass-transfer mathematic model could well simulate the process of tilapia fillet drying by supercritical carbon dioxide. The results can provide some helpful information for the industrial process control of tilapia fillet drying by supercritical CO2.