闪光法测定半透光物质热扩散率
来源期刊：中南大学学报(自然科学版)2000年第6期
论文作者：刘雄飞 薛健 傅友君
文章页码：510 - 513
关键词：半透光;热扩散率;正交法
Key words：semi transparent; thermal diffusivity; orthogonal methodt
摘 要：针对传统的闪光法在物理模型上不适于 用来测试半透光物质热扩散率的问题 ,提出了一个新的物理模型 ,该模型根据物质的透光性 ,确定样品对脉冲激光的吸收为指数型 ,建立了相应的微分方程并求得其解析解 .在激光导热仪上对AlN、牛角 2种试样进行了测试 ,采用正交拟合的方法计算了这 2种试样的热扩散率 .结果表明 :2个AlN试样的热扩散率值分别为 0 .482和 0 .5 0 2cm2 ·s-1;2个牛角试样的热扩散率值分别为 1.38× 10 -3 cm2 ·s-1和1.40× 10 -3 cm2 ·s-1;理论拟合曲线与实验曲线基本吻合 ,说明其理论模型正确 ;该理论模型在吸收率趋近于无穷大(即为不透光物质 )时即可转化成Parker方程 ,表明该模型是一个普适的方法 ,Parker方程只是本模型的一个特例 .
Abstract: Aiming at the physical model inapplicability of flash method to measure thermal diffusivity of semi transparent materials, a new physical model was proposed. In the model, according to the permeance of materials, the pulse laser absorption of materials is of exponential type, and the authors establish a relevant differential equation and get a analytical form. On the laser heat conductivity apparatus, thermal diffusivities of AlN and ox horn samples were measured and the results were calculated with the orthogonal fitting method. The results show that the thermal diffusivity of two AlN samples are 0.482 cm 2·s -1 and 0.502 cm 2·s -1 and the thermal diffusivity of two ox horn samples are 1.38×10 -3 cm 2·s -1 and 1.40×10 -3 cm 2·s -1 respectively. The theoretical fitting curves are in agreement with the experimental data quite well, which shows that the theoretical model is suitable and accords with the experiment. When the absorption is close to the infinite, the model is transformed into Parker equation, which shows that this model is generally suitable, and the Parker equation is only a special case of this model.
