Inverse method for the simultaneous estimation of the thermophysical properties of foods at freezing temperatures
Inverse method for the simultaneous estimation of the thermophysical properties of foods at freezing temperatures
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DOI：
10.1016/j.jfoodeng.2016.07.003
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发表时间：
2016-12
影响因子：
5.5
通讯作者：
I. Cornejo;G. Cornejo;Cristian Ramírez;S. Almonacid;R. Simpson
中科院分区：
文献类型：
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作者：
I. Cornejo;G. Cornejo;Cristian Ramírez;S. Almonacid;R. Simpson
由于冷冻食品的质量和保质期在很大程度上取决于冷冻处理时间，因此其准确估计是高度相关的。此外，由于很难建立一个可靠而准确的数学模型，而且需要为各种各样的食品提供适当的热物理特性，因此冷冻时间的估计是一项艰巨的任务。同时确定导热系数（k（T））和表观体积比热（C（T））的逆方法的能力在冷冻温度范围内的食物（即，设计了实验和验证实验，目的是系统分析和评估反向程序同时测定冷冻温度范围内食品热物理性质的潜在能力。假设一个一维的冷冻过程和已知的热物理性质的食品材料，温度产生在不同位置的食品样品通过数值求解热传导的偏微分方程。设计了求解热物性方程C（T）和k（T）未知参数的反演方法，考察了该方法在冻结温度范围内同时测定C（T）和k（T）的能力，确定了该方法的准确性、快速性和对典型测量误差的鲁棒性。这一事实得到了灵敏度系数分析的支持，该分析将直接调整与逆方法进行了比较。
Because the quality and shelf life of a frozen food greatly depend on the freezing processing time, its accurate estimation is highly relevant. In addition, the estimation of the freezing time is an enormous task due to the difficulty in developing a robust and accurate mathematical model and the need for appropriate thermophysical properties for an immense variety of foods.The objective of this study was to explore, via simulation, the capability of an inverse method to simultaneously determine the thermal conductivity (k(T)) and apparent volumetric specific heat (C(T)) of foods in the freezing temperature range (i.e., initial freezing point to −40 °C).Experiments and validation experiments were designed with the purpose of a systematic analysis and assessment of the potential capability of an inverse procedure for simultaneously determining the thermophysical properties of foods in the freezing temperature range. Assuming a one-dimensional freezing process and known thermophysical properties of the food material, temperatures were generated at different locations of the food sample by numerically solving the partial differential equation for heat conduction. The inverse method was designed to obtain the unknown parameters for the equations of the thermophysical propertiesC(T)andk(T).The ability of the inverse method to simultaneously determineC(T)andk(T)in the freezing temperature range was investigated, and it was determined that the technique is accurate, rapid and robust to typical measurement errors. This fact was supported by a sensitivity coefficient analysis, which compared the direct-adjustment to the inverse method.