球性食品真空冷却非稳态过程的数值分析

Simulation of Unsteady Vacuum Cooling of Sphere-Shaped Foods

通过引入食品材料透气性参数和食品内部到表面的最短距离,建立了食品真空冷却过程的传热模型。在此基础上,采用用户自定义函数编程,首次基于FLUENT模拟了球形食品真空冷却过程。以卷心菜真空冷却为例进行了实验验证,结果显示模拟值和实验值吻合性较好,并对模拟结果进行了分析。研究结果表明:食品材料的透气性和形状对真空冷却过程中食品内部温度场的分布有显著的影响,透气性越好、食品内部到表面的最短距离越小,温度分布越均匀。FLUENT模拟为研究食品真空冷却提供了新途径。

The unsteady vacuum cooling of a variety of compact,spherical-shaped foods was modeled in terms of its air permeability and the shortest distance from its center to its surfaces.For the first time,the vacuum cooling process was simulated with the software package,FLUENT,on the basis of the newly-developed model.In addition,quite a few fresh cabbages,exemplifying the fairly compact,spherical-shaped food,were vacuum cooled to test the simulated results.Both the measured and simulated results show that its air permeability and its radius strongly affect the temperature distribution inside the food.For example,higher air permeability and smaller radius lead to more uniform temperature distribution during vacuum cooling.