塑料.导热率和热扩散率的测定.第2部分:瞬态平面热源（热盘）法

[中文适用范围]： 该文件规定了测定导热率和热扩散率的方法，从而测定单位体积塑料的比热容。 实验布置可以设计成匹配不同的样本尺寸。 可以在一定温度和压力范围内的气体和真空环境中进行测量。 该方法为测试均质和各向同性材料以及具有单轴结构的各向异性材料提供了指导。 材料的均匀性遍及整个样本，并且在探测深度（见 3.1）定义的范围内不存在热障（除了探头旁边的热障）。 该方法适用于导热系数 λ 值在大约范围 0,010 W∙m−1∙K−1 < λ < 500 W∙m−1∙K−1 的材料，热扩散率 α 值在大约范围内范围 5 × 10−8 m2∙s−1 < α < 10−4 m2∙s−1，温度 T 的近似范围为 50 K < T < 1000 K。 注 1：单位比热容体积，C，C = ρ ∙ cp，其中 ρ 是密度，cp 是恒压下单位质量的比热，可通过将导热系数 λ 除以热扩散系数 α 得到，即 C = λ/α，近似范围为 0,005 MJ∙m−3∙K−1 < C < 5 MJ∙m−3∙K−1。 它也称为体积热容。 注 2：如果目的是确定非均质产品（例如装配式面板）或非均质材料板沿厚度方向的热阻或表观导热系数，请参考 ISO 8301、ISO 8302和 ISO 472。 只要注意尽量减少热对流，也可以确定液体的热传输特性。 [外文原描述]： This document specifies a method for the determination of the thermal conductivity and thermal diffusivity, and hence the specific heat capacity per unit volume of plastics. The experimental arrangement can be designed to match different specimen sizes. Measurements can be made in gaseous and vacuum environments at a range of temperatures and pressures. This method gives guidelines for testing homogeneous and isotropic materials, as well as anisotropic materials with a uniaxial structure. The homogeneity of the material extends throughout the specimen and no thermal barriers (except those next to the probe) are present within a range defined by the probing depth(s) (see 3.1). The method is suitable for materials having values of thermal conductivity, λ , in the approximate range 0,010 W∙m −1 ∙K −1 < λ < 500 W∙m −1 ∙K −1 , values of thermal diffusivity, α , in the range 5 × 10 −8 m 2 ∙s −1 < α < 10 −4 m 2 ∙s −1 , and for temperatures, T , in the approximate range 50 K < T < 1 000 K. NOTE 1 The specific heat capacity per unit volume, C , C = ρ ∙ c p , where ρ is the density and c p is the specific heat per unit mass and at constant pressure, can be obtained by dividing the thermal conductivity, λ , by the thermal diffusivity, α , i.e. C = λ / α , and is in the approximate range 0,005 MJ∙m −3 ∙K −1 < C < 5 MJ∙m −3 ∙K −1 . It is also referred to as the volumetric heat capacity. NOTE 2 If the intention is to determine the thermal resistance or the apparent thermal conductivity in the through-thickness direction of an inhomogeneous product (for instance a fabricated panel) or an inhomogeneous slab of a material, reference is made to ISO 8301, ISO 8302 and ISO 472. The thermal-transport properties of liquids can also be determined, provided care is taken to minimize thermal convection.