fluent中udf材料的物性参数，代码中为材料的密度与导热系数-Physical parameters fluent in udf material, the code for the material density and thermal conductivity

水蒸气与空气按质量分数混合后的物性参数质量加权平均——fluent udf 源文件(The mass average of the physical parameters of the mixture of water vapor and air by mass fraction)