在散热介质中通过电磁波动进行尺度依赖的热传输
Matthias Krüger1, Kiryl Asheichyk2, Mehran Kardar3
1Institute for Theoretical Physics, University of Göttingen, 37077 Göttingen, Germany.
Physical review letters
|March 22, 2024
概括
我们提出了使用电磁波进行热传输的理论,揭示了非局部导热张量. 这种张量对于理解各种介质中的热传递至关重要,特别是接近接口的热传递.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 电磁主义 电磁主义
- 热力学是一种热力学.
背景情况:
- 热传输通常由富里埃定律描述,假设局部相互作用.
- 电磁波在介质内的热传输中的作用经常被忽视.
- 了解纳米系统和近接口中的导热率至关重要.
研究的目的:
- 开发一种由电磁波介导的热传输的综合理论.
- 导出适用于任何系统的空间非局部导热张量.
- 调查电磁对导热性的贡献的重要性.
主要方法:
- 开发一个理论框架,用于电磁波介导的热传输.
- 使用电磁格林的函数和潜力推导导热导电张量.
- 在光学稀释和密集介质中分析热传输,包括带接口的系统.
主要成果:
- 导出了一个空间非局部导热张量,取决于电磁性质.
- 热导率的电磁成分在光学稀释介质中可能很重要,表现出里埃和不受阻碍的传输模式.
- 对于具有接口的密度较高的介质,如纳米薄膜,电磁贡献是相关的,导致诸如缺乏里埃模式之类的现象.
结论:
- 电磁波传播显著影响热传输,特别是在具有接口或低光密度的系统中.
- 衍生出的非局部导热张量提供了在各种材料系统中更准确地描述热传递.
- 这项工作强调了考虑电磁效应对于先进材料和设备中精确的热管理的重要性.
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
01:17Magnetic Damping
454
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
454
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
01:30Electromagnetic Waves in Matter
3.0K
Electromagnetic waves can travel in the vacuum as well as in matter. For example light, which is an electromagnetic wave, can travel through air, water, or glass.
Consider the electromagnetic wave passing through a dielectric medium. In such a case, Maxwell's equations get modified. In Ampere's law, ε0 , the dielectric permittivity of free space is replaced with ε, the permittivity of dielectric. Also, the vacuum permeability μ0 is replaced by the permeability of the...
Consider the electromagnetic wave passing through a dielectric medium. In such a case, Maxwell's equations get modified. In Ampere's law, ε0 , the dielectric permittivity of free space is replaced with ε, the permittivity of dielectric. Also, the vacuum permeability μ0 is replaced by the permeability of the...
3.0K
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
01:22Energy Carried By Electromagnetic Waves
3.0K
Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes, this energy is obvious, such as in the summer sun's warmth. At other times, it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves bring energy into a system through their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. However, there is energy in an electromagnetic wave,...
3.0K