282-冰箱冻结过程中食品热值传递的理论分析和冻结过程模拟.pdfVIP

冰箱冻结过程中食品热值传递的理论分析 和冻结过程模拟 Theoretical Analysis and Freezing Process Simulation of Food Heat Transfer in Freezing Process of Refrigerator 上海海洋大学 唐婉 摘 要：速冻是重要的食品保鲜技术之一，符合当代人们对绿色、方便、保健的三大要 求。本文以冰箱冻结牛肉为研究对象，考虑牛肉冻结过程中变物性特点，采用等效热容法处 理相变潜热，然后用计算流体力学（CFD）数值模拟技术对该冻结过程进行模拟并建立描述 三维食品冻结过程的微分方程，通过数值模拟得出冻结时间的模拟值，各测点（T1、T2、T3、 T4、T5）模拟计算的冻结时间与实验冻结时间的误差分别为 5.45%、3.9%、5.8%、4.24%、 9.6%，各点实时温度的模拟平均误差是 1.79℃。结果表明，数值模拟能较好地预测牛肉的 冻结时间。 关键词：数值模拟，冻结时间，食品冻结，冰箱 Abstract: Freezing is recognized as one of the important technology in food preservation, which is in keeping with contemporary three requirements of green, convenience, health care. Beef frozen in a refrigerator was selected as the research object. Because of the change of physical characteristics in beef under the process of the freezing, the equivalent heat capacity method was used to process latent heat in phase change, and the computational fluid dynamics (CFD) numerical simulation technology was used to simulate the freezing process and establish the differential equations of three dimensional food freezing process. Through the numerical simulation of freezing time, the error between each experimental measuring point (T1, T2, T3, T4 and T5) value and simulation calculation of freezing time was listed as fellows respectively 5.45%, 3.9%, 5.8%, 4.24%, 5.8%, each point temperature real-time simulation of the average error was 1.79 ℃. The results showed that the numerical simulation could predict the beef to freeze time well. Keyword: Numerical simulation; Freezing time; Food freezing; Refrigerator 1 引言 预测食品冻结时间，是对食品冻结过程研究的重要课题之一，冻结时间是衡量冻结设备 [1-2] 优劣的重要标准，也是评价冻结食品品质的影响因素之一 。前人关于食品冻结时间的计 [3] 算做了大量研究，周小清等 对比了现有的计算冻结时间的几种模型，研究发现对于液氮冻 [4] 结圆柱状食品，国际制冷协会计算模型最为准确。Pham Q T