Thermal conductivity of polymethyl methacrylate (PMMA) and borosilicate crown glass BK7
Thermal conductivity of polymethyl methacrylate (PMMA) and borosilicate crown glass BK7
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DOI：
10.1007/s10765-005-8106-5
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发表时间：
2005-09-01
影响因子：
2.2
通讯作者：
Metaxa, IN
中科院分区：
文献类型：
--
作者：
Assael, MJ;Botsios, S;Metaxa, IN
研究了有机玻璃和硼硅冕玻璃BK7的导热性能。采用了瞬态热线技术，测量范围为室温至350 K（PMMA）和500 K（BK 7）。该技术在这里应用于一种新的方式，最大限度地减少所有剩余的热接触电阻。这允许设备以绝对方式并且以非常低的不确定性操作。该方法在热线和被测固体之间使用软硅膏材料。在20 μ s至5 s的时间段内测量导线响应于电加热步骤的瞬时温升，可以绝对确定固体以及硅膏的热导率。该方法是基于一个完整的理论模型与方程求解的二维有限元法应用于精确的几何形状。在95%置信水平下，PMMA和BK 7的热导率测量的标准偏差分别为0.09%和0.16%，而该技术的标准不确定度小于1.5%。
The thermal conductivity of polymethyl methacrylate (PMMA) and borosilicate crown glass BK7 has been studied. The transient hot-wire technique has been employed, and measurements cover a temperature range from room temperature up to 350 K for PMMA and up to 500 K for BK7. The technique is applied here in a novel way that minimizes all remaining thermal-contact resistances. This allows the apparatus to operate in an absolute way and with very low uncertainty. The method makes use of a soft silicone paste material between the hot wires and the solid under test. Measurements of the transient temperature rise of the wires in response to an electrical heating step over a period of 20 mu s up to 5 s allow an absolute determination of the thermal conductivity of the solid, as well as of the silicone paste. The method is based on a full theoretical model with equations solved by a two-dimensional finite-element method applied to the exact geometry. At the 95% confidence level, the standard deviations of the thermal conductivity measurements are 0.09% for PMMA and 0.16% for BK7, whereas the standard uncertainty of the technique is less than 1.5%.