Prediction of Thermal Transport in Nonmetallic Materials at Ultra-high Temperatures

许多尖端技术的发展都需要超高温的工作环境。例如，下一代燃气轮机需要能够在1300摄氏度下工作，以提高效率并节省能源。下一代高超音速客机和再入飞行器需要在前缘承受1000-3000摄氏度的高温而不发生材料损失。下一代核裂变工厂和其他火力发电厂希望在更高的温度下工作，以获得更高的能量转换效率和更低的温室气体排放。未来核聚变工厂的发展需要更高的温度。所有这些技术都需要在超高温下对热流进行有效管理。然而，材料在超高温下的基本热输运过程仍不清楚。因此，有必要发展理论以获得深刻的理解，并进行模拟以准确预测超高温下的热传输，以实现技术革命。该项目旨在解决热传输中的一个关键问题：最先进的理论大大低估了大多数晶体在室温下的热导率，并随着温度的升高而进一步恶化。该项目的目标是揭示基本的热传输机制，并准确预测非金属材料从低温到超高温的热导率。该提案设想了三个主要焦点：（i）将完全依赖于温度的原子间相互作用纳入预测，并验证概念验证发现，即这种努力通常可以解决高温下普遍存在的热导率预测不足问题;（ii）开发五热载体相互作用过程的形式化，这在高温下可能很重要;开发一种方法，通过准确预测介电函数，充分预测光子对固体热输运的贡献。该项目将实现五种热载体相互作用的预测，这将是潜在的变革，因为它们是所有固体中固有的热传输机制，几十年来科学家们一直难以捉摸。它将回答两个紧迫的问题：在一般固体中，在什么温度下五热载体相互作用是重要的？在低温下，在哪些系统中，五种热载体的相互作用是重要的？该项目还将严格预测和验证高温下热辐射对热导率的贡献。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

The development of many cutting-edge technologies requires an ultra-high-temperature working environment. For example, the next-generation gas turbines need to be able to work at 1300 degrees Celsius, to boost efficiency and save energy. The next-generation hypersonic passenger aircraft and re-entry vehicles need to withstand 1000-3000 degrees Celsius at the leading edges without material loss. The next-generation nuclear fission plant and other thermal power plants are desired to work at higher temperatures for higher energy-conversion efficiency and lower greenhouse gas emissions. The development of future fusion plants requires even higher temperatures. All these technologies require effective management of heat flow at ultra-high temperatures. However, the fundamental thermal transport processes in materials at ultra-high temperatures remain unclear. It is therefore necessary to develop theories to gain a deep understanding and conduct simulations to accurately predict thermal transport at ultra-high temperatures in order to realize technology revolutions. This project addresses a critical issue in thermal transport: state-of-the-art theories significantly underpredict the thermal conductivity of most crystals at room temperature and further worsen as the temperature increases.The goal of this project is to unveil the fundamental thermal transport mechanisms and accurately predict the thermal conductivity of nonmetallic materials from low to ultra-high temperatures. The proposal envisions three major foci: (i) incorporate the fully temperature-dependent interatomic interaction into the predictions and validate the proof-of-concept finding that such effort can generally solve the universal thermal conductivity under-prediction problem at high temperatures; (ii) develop formalisms for five-heat carrier interaction processes, which can be important at high temperatures; (iii) develop a method that can fully predict the photon contribution to thermal transport in solids through accurate prediction of the dielectric function. The project will enable five-heat carrier interaction predictions, which will be potentially transformative because they are intrinsic thermal transport mechanisms in all solids and have been elusive to scientists for decades. It will answer two pressing questions: In general solids, at what temperatures is the five-heat carrier interaction important? At low temperatures, in which systems is the five-heat carrier interaction important? This project will also rigorously predict and validate the thermal radiation contribution to thermal conductivity at high temperatures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.