考虑约束的材料热传导系数辨识方法

Constrained estimation method of thermal conductivity of a material

材料热传导系数的辨识是一类典型的热传导逆问题。本文建立了辨识随温度变化的热传导系数的遗传算法,并通过辨识增量和引入罚函数等方法,考虑了一类典型防热材料热传导系数值随温度增加不减小的物理约束,以及一项工程应用中的约束,即温度较高时温度的仿真计算结果应高于温度实测值,建立起了考虑约束的材料热传导系数辨识方法。通过典型算例的分析计算结果表明,所建立的辨识算法是有效的,克服了原有算法在测量误差较大情况下辨识结果出现非物理振荡的不足,辨识结果也具有更强的工程实用价值。

Estimation of the thermal conductivity of a material is a typical inverse heat conduction problem(IHCP).The temperature-dependant thermal conductivity estimation method of genetic algorithms(GA)is presented.A physical practical constraint that the value of thermal conductivity of a typical thermal protection material should not decrease with the temperature increasing,and a engineering practical constraint that the predicted temperature should be greater than the measurement values when the temperature is high,are taken into account in the algorithms.Then,the constrained estimation algorithm of thermal conductivity is developed by two methods,i.e.,the increments estimation method and the penalty function method.After applying these constrained estimation methods to a typical case,it is found that,these estimation methods are feasible and they can overcome the shortcoming of the original unconstrained estimation method that some unphysical oscillations may appear in the estimation result when the measurement noise is significant.The estimated results are of more engineering meanings in practical applications.