固体导热率的测定.docVIP

固体导热系数的测定 （辽宁科技大学 材料与冶金学院 学号：1） 摘要：导热系数是表征物质热传导性质的物理量，材料结构的变化与所含杂质的不同对材料导热系数有明显的影响。实验方法分为稳态法和动态法两类。在稳态法中，先利用热源对样品加热，样品内部的温差使热从高温出向低温去传导。内部温度将随加热快慢和传热快慢的影响而变动。导热系数是应用材料时的一个设计参数，在加热器、散热器、传热管道设计等工程实践中都要涉及这个参数。因此它是有实际意义。本实验仅用稳态法测不良导体的导热系数其设计思路清晰、简洁。原理主要依据傅里叶热传导方程。 关键词：导热系数、傅里叶热传导、误差 Liaoning university of science and technology School of material and metallurgy Excellent Metallurgical engineering 12 Abstract Coefficient of thermal conductivity is heat conduction properties of physical quantities, Impurities contained different with the change of material structure has obvious influence on material coefficient of thermal conductivity. The experiment method is divided into two categories, steady state method and dynamic method. In the steady state method, the first use of heat source heating of the sample, the sample internal temperature difference of heat from the high temperature to low temperature to conduction. The internal temperature will vary with the heating speed and the influence of heat transfer speed. Coefficient of thermal conductivity is one of the application materials, the design parameters in the heater, radiator, heat transfer pipeline design of engineering practice should be involved in this parameter. Thus it has a practical significance. This experiment only by steady state method to measure the thermal conductivity of poor conductor is designed with clarity, concise. The principle of main basis Fourier heat conduction equation. Keywords Coefficient of thermal conductivity, Fourier heat conduction, error 1.引言 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。由于导热系数与物质成分、微观结构、温度、压力及杂质含量密切相关，所以在科学实验和工程设计中材料的导热系数常常需要由实验去具体测定。 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。本实验将利用稳态法测量导体的导热系数。 2 实验原理 傅里叶在研究了固体的热传定律后，建立了导热定律。他指出，当物体的内部有温度梯度存