几何边界条件对导热系数测量值的影响

在用稳态法对不良导体导热系数测量的实验中，发现样品的几何边界条件对导热系数的测量值是有很大影响的，在工程学上一般认为当扁圆柱形样品的厚度小于半径的1／10时，这一影响就可忽略。但实验指出，可忽略的几何边界条件受样品本身的导热性制约。本研究可以对未知材料的导热性先给出粗略的判断，然后再确定适于实验的样品的几何边界条件，以提高测量的精确度。

Effect on Measuring Data of Coefficient of Thermal Conductivity by Geometrical Boundary Condition

In the experiment to measure coefficient of thermal conductivity of poor conductors by steady condition method, it is found that geometrical boundary condition of sample has great effect on the measured data of coefficient of thermal conductivity. In engineering, it is commonly considered that the effect can be ignored when the thickness is less than 1/10 radius for flat column materials. But the experiment shows that the ignored boundary condition would be restricted by the character of its thermal conductivity. This research can give rough judgment on the thermal conductivity of unknown material as a sample, and ascertain its geometrical boundary condition to fit the experiment so as to improve the metrical preciseness.