摘要：颗粒材料在工业生产和工程中有着广泛的应用，但由于堆积过程中颗粒的分散性和颗粒之间相互作用的复杂性，缺少准确的模型来描述颗粒堆积层的传热性能。因此，对颗粒材料堆积层的热传导的相关理论和数值模型的研究必要的。导热系数作为分析材料热性质最基本的参数，必须对其进行精确测量。本文针对颗粒材料堆积层的传热性能，设计了基于防护热板法的导热系数测试实验台，利用成圆率较高的玻璃微珠作为实验对象，通过合理设置实验中的粒径、温度和厚度等影响因素，探究颗粒材料的当量导热系数（导热、对流、辐射三者相互影响的综合传热系数)的变化规律，为颗粒材料传热性能的进一步研究提供数据支持和分析方法。

关键词 当量导热系数；堆积颗粒；防护热板法

毕业设计说明书外文摘要

Title  Research on Thermal Conductivity of Glass Beads

Abstract：Particulate materials are widely used in industrial production and engineering. Due to the dispersion of particles during the accumulation process and the complexity of the interaction between particles, the lack of accurate models to describe the heat transfer properties of the particles deposited layer. Therefore, the study of the relevant theory and numerical model of the thermal conductivity of the granular materials is necessary. The thermal conductivity is the main parameter to characterize the thermal physical properties of the material. Its accurate evaluation is of great significance to the thermal properties of the granular materials. In this paper, the glass microspheres with high roundness were used as the experimental objects.  The  factors influencing the thermal conductivity (conduction, convection and radiation) of the granular materials were investigated by reasonably setting the factors such as particle size, temperature and thickness. The experiments provide data support and analysis method for the further study of the heat transfer performance of particulate materials.

Keywords: Equivalent thermal conductivity; Packing particles; Protective hot plate method

目次

1绪论 1

1.1研究背景及意义 1

1.2国内外研究进展 2

1.3本文拟研究的主要内容 3

2仪器工作原理与总体设计 5

2.1导热基本定律 5

2.2防护热板法测颗粒材料导热系数基本原理 6

2.3仪器总体设计 7

2.4仪器接触热阻分析及误差校正 7

2.5本章小结 7

3仪器重复性验证 8

4实验结果及分析 18

4.1玻璃微珠的物理性质及粒径分布 18

4.2实验步骤 21

4.3导热系数测量实验结果 24

4.4本章小结 26

结论 27

致谢 28

参考文献 29

1 绪论

1.1 研究背景及意义

工业生产中的许多材料均以颗粒的形式存在，建筑用材如石英砂、混凝土等，能源燃料如煤粉等，农业产品如小麦、稻米等，广泛存在于生产和生活中，是人类必不可少的材料之一。