光学热带法测量固态材料热物性研究

针对接触式瞬态热带法测量导热系数时,加热丝和样品间接触热阻,会影响实验测量结果以及对固体样品形状大小要求较高的现状,根据瞬态热带法原理,本文提出了一种光学瞬态热带法来测量固体材料的导热系数。采用连续激光为加热源,通过透镜将光斑放大并聚焦照射在样品表面,实现样品非接触式测量。构建二维导热模型,采用红外热像仪记录样品表面温升随时间的变化关系,根据导热理论模型求出待测样品的热扩散系数及导热系数。以K9和石英玻璃为样品对本套测量方法进行验证,制备并测量了纯石蜡、0.5%和1%石墨烯-石蜡的固态复合相变材料的导热系数,探讨了影响实验结果的潜在因素。

Thermal conductivity measurements of solid materials by optical hot-strip method

In view of the existence of the contact thermal resistance that cannot be ignored in the current transient hot-strip method to measure the thermal conductivity, the problems affecting the experimental measurement results and the high requirements on the shape and size of solid samples, an optical transient hot wire method is proposed in this paper according to the principle of transient hot-strip method. By using continuous laser as the heating source, the spot is amplified and focused on the surface of the sample through a lens, and the sample non-contact measurement is realized. A two-dimensional thermal conductivity model has been constructed, and infrared thermography has been used to record the relationship between the surface temperature rise of the sample and the change of time. Based on the theoretical heat conduction model, the thermal diffusivity and thermal conductivity of the sample to be measured have been calculated. The new method has been validated using K9 and quartz glass as samples, then the thermal conductivity of pure paraffin, 0.5% and 1% graphene-paraffin solid composite phase change materials have been prepared and measured, and the potential factors influencing the experimental results have been discussed.