Acquisition of a Laser-Flash Apparatus for Measurement of Thermal Diffusivity to 2000C

购置激光闪光装置，用于测量 2000C 的热扩散率

• 批准号: 0132275
• 负责人: Anne Hofmeister
• 金额: $ 13.03万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0132275&HistoricalAwards=false
• 关键词: Acquisition; Laser; Flash; Apparatus; Measurement

0132275HofmeisterHeat transport pertains to problems on all scales in Earth science, e.g., laboratory experiments, crystallization and texture of igneous rocks, ductile faulting, mantle plumes, Earth's convection patterns, and planetary formation and evolution. Understanding such processes requires knowledge of either the thermal diffusivity (D) or the thermal conductivity (k = DrCV ). The physical property k describes the rate at which heat flows from the hot to the cold end of a rigid material, and thus pertains to conductive processes. When the material flows as well (convective processes), D applies. Because density (r) and heat capacity (CV) at temperature are well-constrained or readily predicted, measurements of D provide the data needed to understand heat transport. However, the temperature dependence of D is generally unknown for geological and planetary materials and the available data are inconsistent. Disparities exist in the previous methods because heat is transported as light over the short scales of the experiments in a manner that is specific to a given experiment. The results are thus not a material property. This complex situation exists because planetary materials are transparent at some wavelengths of light (and light is heat). Technological advances in materials science have led to a device which overcomes this problem. Funds from this grant will support acquisition of such a laser-flash apparatus to measure thermal diffusivity (D) from room temperature to 2000oC. No comparable instrument exists in Earth Science research facilities in the U.S. The apparatus not only doubles the 1000oC range typical for the scant existing data, most of which are 30 years old, but is easy and rapid to use, and provides D(T) on melts. The data generated by the laser flash apparatus provide the needed tests for the T dependence for phenomenological models for k. Combining theory and experiment not only allows extrapolation of measured D and k to all conditions of interest to Earth science, but will further our understanding of the microscopic basis of transport properties.***

0132275Hofmeister热传输涉及地球科学中所有尺度的问题，例如实验室实验、火成岩的结晶和结构、延性断层、地幔羽流、地球对流模式以及行星的形成和演化。了解此类过程需要了解热扩散率 (D) 或热导率 (k = DrCV )。物理属性 k 描述热量从刚性材料的热端流向冷端的速率，因此与传导过程有关。当材料也流动时（对流过程），D 适用。 由于温度下的密度 (r) 和热容 (CV) 受到良好约束或易于预测，因此 D 的测量提供了了解热传输所需的数据。 然而，对于地质和行星材料来说，D 的温度依赖性通常是未知的，并且可用数据不一致。先前的方法存在差异，因为热量以光的形式在实验的短尺度上以特定实验特有的方式传输。因此，结果不是物质属性。 这种复杂情况的存在是因为行星材料在某些波长的光下是透明的（而光就是热）。材料科学的技术进步已经产生了克服这个问题的装置。这笔赠款的资金将支持购买此类激光闪光设备，以测量从室温到 2000oC 的热扩散率 (D)。美国的地球科学研究设施中没有类似的仪器。该设备不仅将现有数据（其中大部分已有 30 年历史）的 1000oC 范围扩大了一倍，而且使用起来方便快捷，并提供 D(T)融化。激光闪光装置生成的数据为 k 现象学模型的 T 依赖性提供了所需的测试。 理论与实验的结合不仅可以将测量的 D 和 k 外推到地球科学感兴趣的所有条件，而且将进一步加深我们对输运特性的微观基础的理解。***