增强近场辐射传热的角形和边缘模式
Lei Tang1, Lívia M Corrêa2, Mathieu Francoeur3,4
1Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA, USA.
Nature
|April 17, 2024
概括
纳米结构中的角和边形模式显著增强了近场辐射热传递 (NFRHT). 这项研究表明,在双纳米系统中,NFRHT占主导地位的新机制.
科学领域:
- 物理
- 纳米技术
- 热传输
背景情况:
- 近场辐射热传递 (NFRHT) 可以超越黑体极限由于 evanescent 模式.
- 纳米结构在角落和边缘支持局部电磁模式,但它们的NFRHT贡献尚未被探索.
研究的目的:
- 通过角落和边缘模式研究和证明NFRHT的增强.
- 探索这些模式在双纳米系统中的优势.
主要方法:
- 对NFRHT进行理论建模和实验验证.
- 使用两个共平面的20纳米厚的碳化膜和100纳米的真空间隙.
主要成果:
- 测量和预测的NFRHT系数为830 W m-2 K-1,比无限表面高5.5倍.
- 角形和边缘模式占NFRHT总量的81%,主导了增强.
- 观察到的NFRHT比给定几何体的黑体极限大1400倍.
结论:
- 角和边形模式显著增强NFRHT,特别是在双纳米级模式下.
- 这种机制为先进的热管理和能量转换应用提供了途径.
相关概念视频
01:20Mechanisms of Heat Transfer II
3.2K
In convection, thermal energy is carried by the large-scale flow of matter. Ocean currents and large-scale atmospheric circulation, which result from the buoyancy of warm air and water, transfer hot air from the tropics toward the poles and cold air from the poles toward the tropics. The Earth’s rotation interacts with those flows, causing the observed eastward flow of air in the temperate zones. Convection dominates heat transfer by air, and the amount of available space for the airflow...
3.2K
01:14Mechanisms of Heat Transfer
322
Heat transfer between the human body and its environment occurs through four main mechanisms: conduction, convection, radiation, and evaporation.
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
Conduction, accounting for approximately 3% of body heat loss at rest, is the process of exchanging heat between molecules of two materials in direct contact. This can result in both heat loss and gain. For instance, when the body is submerged in water, which conducts heat 20 times more effectively than air, it can either lose or gain significant...
322
01:19Mechanism of heat transfer
1.2K
Understanding heat transfer mechanisms is essential for understanding how our bodies maintain balance in different environmental conditions. When the environment is thermoneutral, the body is in a state of balance, neither using nor releasing energy to maintain its core temperature. However, when the environment is not thermoneutral, the body employs four heat transfer mechanisms to maintain homeostasis: conduction, convection, evaporation, and radiation. These mechanisms facilitate heat...
1.2K
01:14Mechanisms of Heat Transfer I
4.2K
Just as interesting as the effects of heat transfer on a system are the methods by which the heat transfer occur. Whenever there is a temperature difference, heat transfer occurs. It may occur rapidly, such as through a cooking pan, or slowly, such as through the walls of a picnic ice box. So many processes involve heat transfer that it is hard to imagine a situation where no heat transfer occurs. Yet, every heat transfer takes place by only three methods: conduction, convection, and radiation.
4.2K
01:05Absorption of Radiation
726
The rate of heat transfer by emitted radiation is described by the Stefan-Boltzmann law of radiation:
726
01:17Radiation: Applications
1.1K
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
1.1K