本文提出一种在第三类边界条件下,通过理论计算蒸发规律与实测蒸发规律之间的最佳逼近,瞬态测定计算变物性质扩散系数的参数估计方法。设计并制造了真空蒸发实验装置。在假设质扩散系数为舍湿量线性函数的情况下,对石膏板和水泥板的质扩散系数进行了测量计算。实验和计算结果表明,测试及计算方法简单可行,容易进行控制,测定时间较稳态方法大大缩短,因此比较实用可靠。 In this paper, we propose a method to estimate the diffusivity of the matter properties by the best approximation between the evaporation law and the measured evaporation rule under the third type of boundary conditions. Design and manufacture of vacuum evaporation experimental device. Under the assumption that the mass diffusion coefficient is a linear function of the amount of wetting, the mass diffusion coefficients of gypsum board and cement board are measured and calculated. Experiments and calculation results show that the test and calculation method is simple and feasible, easy to control, the measurement time is much shorter than the steady state method, so more practical and reliable.