穩态法测固体导热系数的测量.docVIP

固体导热系数的测量 Measurement of thermal conductivity of solid 摘要： 导热系数是表征物质热传导性质的物理量，对保温材料要求其导热系数尽量小，对散热材料要求其导热系数尽量大Abstract:?????Material thermal conductivity is characterized by physical properties of thermal conductivity of insulation material requirements of its thermal conductivity as small as possible, on the cooling requirements of its thermal conductivity material as large as possible.?????Method of measuring thermal conductivity of more, but the basic method can be grouped into two categories: one is the steady state, and the other for the dynamic method.? Steady-state method, first with the heat source to heat the test sample and the sample to form a stable internal temperature distribution, and then measured in the dynamic method, the temperature distribution in the sample is changing with time, for example, by cycle?of change.? 关键词：物质热传导性质Key words: material properties of steady state heat conduction temperature distribution? 引言：测量导热系数的方法比较多，可以归纳为两类基本的方法，一类是稳态法，另一类为动态法。用稳态法时，先用热源对测试样品进行加热，并在样品内部形成稳定的分部，然后进行测量，在动态法中，就是待测样品中的温度随时间的变化而变化在做的时候可能较为复杂，所以本试验采用稳态法进行测量。Introduction: Measurement method of thermal conductivity of more, can be summarized in two basic ways, one is state law, and the other for the dynamic method. Steady-state method, first with the heat source to heat the test sample and the sample to form a stable internal division, and then measured in the dynamic method, that is, the temperature of the sample in the changes over time in doing time may be more complex, so the test method used to measure steady-state 测量导热系数的实验方法一般分为稳态法与动态法两类。在稳态法中，先利用热源对样品加热，样品内部的温差使热量从高温处向低温处传导，样品内部各点的温度将随加热快慢和传热快慢的影响而变动；当适当控制实验条件和实验参数，使加热和传热过程达到平衡状态时，待测样品内部就能形成稳定的温度分布，根据这一温度分布就可计算出导热系数。而在动态法中，最终在样品内部所形成的温度分布是随时间变化的，例如呈周期性的变化，变化的周期和幅度亦受实验条件和加热快慢的影响。、温度分别为、 的平行平面（设 ＞ ），若平面面积均为，在时间内通过面积的热量满足下述表达式： (1) 式中为热流量，即为该物质的热导率（又称作导热系数）。在数值上等于相距单位长度的两平面的温度相差1个单位时，单位时间内通过单位面积的热量，其单位是W/m.K。本实验仪器如图14-1所示。 在支架D上先放置散热盘C，在散热盘C的上面放上待测样品B（圆盘形的不良导体），再把带发热器的圆铜盘A放在B