包装对食品冻结过程的影响研究  

Study on the Effects of Packaging on Food Freezing

作　　者：王贵强[1] 邹平华[1] 刘明生[1] 刘永鑫[1] 

机构地区：[1]哈尔滨工业大学市政环境工程学院,哈尔滨150090

出　　处：《农业机械学报》2014年第7期171-176,共6页Transactions of the Chinese Society for Agricultural Machinery

基　　金：黑龙江省自然科学基金面上项目(E201309)

摘　　要：通过模拟和实验方法研究食品包装对冻结过程的影响,首先,使用CFD方法模拟食品的冻结条件,包括食品周围空气的温度、流动速度及紊流强度等空气参数,以此来计算得到食品的表面传热系数,然后使用自然对流和辐射换热经验公式计算食品与包装材料之间的空气层内的传热过程,在食品内部每一点应用傅里叶导热公式模拟食品内部的传热过程,最后使用迭代方法将这几部分计算结合起来。在一实际的小型冷库中进行不同包装材料食品的冻结实验,以验证模型的准确性。结果表明,相对于传统的空气层热阻处理方式,该模型能够获得更加准确的计算结果,与实验结果吻合较好。不同包装材料的食品降温曲线差别较大,包装材料与食品之间的空气层对食品冻结过程有很大的影响,其热阻在整个过程中是不断变化的,变化趋势与食品降温曲线相反。The effects of packaging on food freezing was investigated using both modeling and experimental methods. First, CFD method was employed to model the freezing condition of food in freezing chamber, including air temperature, air velocity and turbulent intensity, which was then used to calculate the surface heat transfer coefficient of food product. Empirical relations for free convection and radiation were used to simulate the heat transfer inside the air layer between food and packaging material. Fourier formula was applied to model the heat transfer inside food. Finally, an iteration scheme was used to combine all parts together. Freezing experiments were conducted in a small freezer to verify the model, which showed encouraging agreements on freezing curves of food at different locations. Packaging has a big influence on food freezing, food with different packaging differs greatly in freezing process. The thermal resistance of air layer in packaging changes in a reverse trend of food temperature drop.

关 键 词：食品冻结 包装 空气层 数学模型 

分 类 号：TB69[一般工业技术—制冷工程]