Related Experiment Video
Updated: Jun 11, 2025
05:20
Characterization of Thermal Transport in One-dimensional Solid Materials
Published on: January 26, 2014
17.3K
Theory and Measurement of Heat Transport in Solids: How Rigidity and Spectral Properties Govern Behavior
1Department of Earth, Environmental, and Planetary Sciences, Washington University, St. Louis, MO 63130, USA.
Materials (Basel, Switzerland)
|September 28, 2024
Summary
Traditional heat transport models are flawed. This study reveals heat transfer in solids relies on radiative diffusion, explaining thermal conductivity and expansivity across temperatures using laser flash analysis data.
Area of Science:
- Solid-state physics
- Materials science
- Thermodynamics
Background:
- Conventional models of heat transport in solids, based on elastic collisions, are inadequate as they treat heat and mass diffusion separately.
- Understanding heat transfer mechanisms in solids is crucial for materials development and thermal management.
Purpose of the Study:
- To develop a more accurate model for heat transport in solids by combining analytical theory with experimental data.
- To investigate the role of radiative diffusion in heat transfer across a wide range of temperatures.
Main Methods:
- Dimensional analysis of Fourier's heat equation to understand thermal diffusivity (D).
- Application of a radiative diffusion model using idealized spectra.
- Experimental validation using laser flash analysis (LFA) for thermal conductivity (K) and thermal expansivity measurements.
Main Results:
- Thermal diffusivity (D) is shown to depend on length-scale, confirmed across metallic, semiconducting, and insulating solids.
- The radiative diffusion model accurately reproduces measured thermal conductivity (K = Dρc) for solids from 0 K to over 1200 K.
- Thermal expansivity is found to be proportional to ρc/Young's modulus, consistent with experimental data.
Conclusions:
- Heat diffusion in solids at laboratory temperatures occurs via absorption and re-emission of infrared light, supporting a radiative diffusion mechanism.
- Material's heat uptake, influenced by light-material interactions, dictates transport properties.
- The proposed radiative diffusion model explains heat transport behavior in solids from near 0 K to above melting point.
Related Concept Videos
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 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
01:14Mechanisms of Heat Transfer
279
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...
279
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
01:17Theory of Metallic Conduction
1.3K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.3K
01:16IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
1.2K
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to...
According to Hooke's law, the vibrational frequency is directly proportional to...
1.2K