反演法求小麦面团在冻结温度范围内的热导率

Thermal Conductivity of Wheat Dough Determined by an Inversion Method within Freezing Temperature

为确定小麦面团在冻结温度范围内的热导率,采用差式量热扫描法测量了3个不同水分含量面团的比热,然后利用COMSOL软件反演求出面团在-30~30℃范围内的热导率。结果表明,面团热导率随水分含量增大(38%~44%)而逐渐升高;且随着温度的降低,面团的热导率逐渐降低,但是当面团的温度降至冰点后,面团的热导率急剧上升,然后又呈缓慢上升趋势。通过对面团热导率与水分含量关系的进一步分析,建立了速冻温度范围内面团热导率随温度和水分含量变化的数学模型。

The specific heats of three doughs with different moisture contents were measured using differential scanning calorimetry( DSC) in order to determine the thermal conductivity of wheat dough within the freezing temperature.Their thermal conductivity within the temperature range of -30℃ to 30℃ was derived using an inverse optimization in the COMSOL software.The results showed that the thermal conductivity increased gradually when the moisture content of the dough increased from 38% to 44%.With the decrease of temperature,the thermal conductivity of the dough gradually decreased. However,the thermal conductivity of doughs rose sharply when the dough temperature dropped just beyond the freezing points,and then slowly increased.Through further analysis of the relationship between thermal conductivity and moisture content of dough,a mathematical model was established for predicting the thermal conductivity of a dough from its temperature and moisture content in the range of quick freezing temperature.