Transient thermal conductivity measurements : comparison of destructive and nondestructive techniques
Transient thermal conductivity measurements : comparison of destructive and nondestructive techniques
复制标题
瞬态热导率测量：破坏性和非破坏性技术的比较
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
N. Mathis
中科院分区：
文献类型：
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作者：
N. Mathis
瞬态热导率方法得益于测试的快速性，但同时这些方法是破坏性的，因为必须制备样品。激光闪光扩散率是一个例子，一个行之有效的瞬态方法测量热导率，这需要样品制备到直径为12.4毫米。新引入的修改热线（MHW）和瞬态平面源（TPS）技术是瞬态的，以及，但在本质上是无损的。这是可能的，因为这两种新技术都是通过在同一表面施加和测量热量来操作的反射方法。基本上可以测量任何平面，没有最大尺寸限制。这些瞬态技术已被用于评估不同尺寸，结构和均匀性的材料。虽然从泡沫到陶瓷的均质材料的结果比较好，但复合材料差异很大。这是因为两种方法对试样的穿透程度不同，其结果是测试深度的反映。由于反射技术中的测试时间不同，因此收集了与热导率相关的信息，该信息是样本垂直位置的函数。技术进行了讨论，并从两个不同的瞬态技术对均匀材料的结果进行了比较。
Transient thermal conductivity methods have benefited from the rapid nature of the testing, but at the same time these methods are destructive because a sample must be prepared. Laser flash diffusivity is an example of a well-established transient method of measuring thermal conductivity, which requires samples to be prepared to a diameter of 12.4 mm. The newly introduced modified hot wire (MHW) and transient plane source (TPS) techniques are transient as well, but are nondestructive in nature. This is possible because both of these new techniques are reflectance methods that operate by applying and measuring heat at the same surface. Essentially any flat surface can be measured, with no maximum size constraints. These transient techniques have been used to evaluate materials of differing size, structure, and homogeneity. While results compare well for homogeneous materials from foams to ceramic, composite materials differ considerably. This is because the two methods penetrate the samples to different degrees, and the results are a reflection of the testing depth. As test times are varied in the reflectance techniques, information was gathered that has been related to the thermal conductivity as a function of position normal to the sample. Techniques are discussed and results on homogeneous materials from two different transient techniques are compared.