scholarly journals Scale Effects in Nanoscale Heat Transfer for Fourier’s Law in a Dissimilar Molecular Interface

ACS Omega ◽  
2020 ◽  
Vol 5 (41) ◽  
pp. 26527-26536
Author(s):  
Md Masuduzzaman ◽  
BoHung Kim
Keyword(s):  
Heat Transfer ◽  
Scale Effects ◽  
Fourier’S Law ◽  
Nanoscale Heat Transfer ◽  
Fourier's Law

Fourier's law of heat transfer and its implication to cell motility

Biosystems ◽  
2005 ◽  
Vol 81 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Tomoaki Kawaguchi ◽  
Hajime Honda ◽  
Kuniyuki Hatori ◽  
Ei-ichi Imai ◽  
Koichiro Matsuno
Keyword(s):  
Heat Transfer ◽  
Cell Motility ◽  
Fourier’S Law ◽  
Fourier's Law

Non-Fourier Heat Conduction in Carbon Nanotubes

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Hai-Dong Wang ◽  
Bing-Yang Cao ◽  
Zeng-Yuan Guo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Flux ◽  
Heat Conduction ◽  
Thermal Inertia ◽  
Energy Relation ◽  
Fourier’S Law ◽  
Fourier Heat Conduction ◽  
Fourier's Law

Fourier’s law is a phenomenological law to describe the heat transfer process. Although it has been widely used in a variety of engineering application areas, it is still questionable to reveal the physical essence of heat transfer. In order to describe the heat transfer phenomena universally, Guo has developed a general heat conduction law based on the concept of thermomass, which is defined as the equivalent mass of phonon gas in dielectrics according to Einstein’s mass–energy relation. The general law degenerates into Fourier’s law when the thermal inertia is neglected as the heat flux is not very high. The heat flux in carbon nanotubes (CNTs) may be as high as 1012 W/m2. In this case, Fourier’s law no longer holds. However, what is estimated through the ratio of the heat flux to the temperature gradient by molecular dynamics (MD) simulations or experiments is only the apparent thermal conductivity (ATC); which is smaller than the intrinsic thermal conductivity (ITC). The existing experimental data of single-walled CNTs under the high-bias current flows are applied to study the non-Fourier heat conduction under the ultrahigh heat flux conditions. The results show that ITC and ATC are almost equal under the low heat flux conditions when the thermal inertia is negligible, while the difference between ITC and ATC becomes more notable as the heat flux increases or the temperature drops.

Non-Fourier Heat Conduction in Carbon Nanotubes

2009 ◽  
Author(s):  
Hai-Dong Wang ◽  
Bing-Yang Cao ◽  
Zeng-Yuan Guo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Heat Flux ◽  
Heat Conduction ◽  
Thermal Inertia ◽  
Energy Relation ◽  
Fourier’S Law ◽  
Fourier Heat Conduction ◽  
Fourier's Law

Fourier’s law is a phenomenological law to describe the heat transfer process. Although it has been widely used in a variety of engineering application areas, it is still questionable to reveal the physical essence of heat transfer. In order to describe the heat transfer phenomena universally, Guo has developed a general heat conduction law based on the concept of thermomass, which is defined as the equivalent mass of phonon gas in dielectrics according to Einstein’s mass-energy relation. The general law degenerates into Fourier’s law when the thermal inertia is neglected as the heat flux is not very high. The heat flux in carbon nanotubes (CNTs) may be as high as 1012 W/m2. In this case Fourier’s law no longer holds. However, what is estimated through the ratio of the heat flux to the temperature gradient by MD simulations or experiments is only the apparent thermal conductivity (ATC); which is smaller than the intrinsic thermal conductivity (ITC). The existing experimental data of single-walled CNTs under the high-bias current flows are applied to study the non-Fourier heat conduction under the ultra-high heat flux conditions. The results show that ITC and ATC are almost equal under the low heat flux conditions when the thermal inertia is negligible, while the difference between ITC and ATC becomes more notable as the heat flux increases or the temperature drops.

An alternative criterion in heat transfer optimization

2010 ◽  
Vol 467 (2128) ◽  
pp. 1012-1028 ◽  
Author(s):  
Qun Chen ◽  
Hongye Zhu ◽  
Ning Pan ◽  
Zeng-Yuan Guo
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Entropy Generation ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Optimization Criterion ◽  
Entransy Dissipation ◽  
Minimum Entropy ◽  
Fourier’S Law ◽  
Fourier's Law

Entropy generation is recognized as a common measurement of the irreversibility in diverse processes, and entropy generation minimization has thus been used as the criterion for optimizing various heat transfer cases. To examine the validity of such entropy-based irreversibility measurement and its use as the optimization criterion in heat transfer, both the conserved and non-conservative quantities during a heat transfer process are analysed. A couple of irreversibility measurements, including the newly defined concept entransy , in heat transfer process are discussed according to different objectives. It is demonstrated that although thermal energy is conserved, the accompanied system entransy and entropy in heat transfer process are non-conserved quantities. When the objective of a heat transfer is for heating or cooling, the irreversibility should be measured by the entransy dissipation, whereas for heat-work conversion, the irreversibility should be described by the entropy generation. Next, in Fourier’s Law derivation using the principle of minimum entropy production, the thermal conductivity turns out to be inversely proportional to the square of temperature. Whereas, by using the minimum entransy dissipation principle, Fourier’s Law with a constant thermal conductivity as expected is derived, suggesting that the entransy dissipation is a preferable irreversibility measurement for heat transfer.

scholarly journals Quasi-Ballistic Heat Transfer From Metal Nanostructures on Sapphire

2011 ◽  
Author(s):  
Austin Minnich ◽  
Gang Chen
Keyword(s):  
Heat Transfer ◽  
Heat Transport ◽  
Free Path ◽  
Mean Free Path ◽  
Phonon Transport ◽  
Minimum Size ◽  
Metal Nanostructures ◽  
Fourier’S Law ◽  
Length Scales ◽  
Fourier's Law

Quasi-ballistic phonon transport, where heat transfer does not obey Fourier’s law, occurs when length scales become comparable to the phonon mean free path (MFP). Understanding this regime of heat transport is of fundamental interest, as the manner in which the heat transport deviates from Fourier’s law reveals important information about the phonon mean free path distribution. While ultrafast techniques can provide the time resolution to observe heat transfer in this regime, the minimum size of the heated region is restricted by diffraction to approximately 1 μm, which is larger than phonon MFPs in many materials. To circumvent this limit, we study heat transfer from metallic dot arrays with sub-micron diameters on sapphire fabricated using electron beam lithography. We describe heat transfer models which allow us to determine how the heat transfer in sapphire deviates from Fourier’s law at these small length scales. Our results indicate that quasi-ballistic transport occurs in sapphire when length scales are on the order of hundreds of nanometers.

scholarly journals Slip Flow of a Nanofluid Over a Stretching Cylinder with Cattaneo-Christov Flux Model: Using SRM

2018 ◽  
Vol 7 (4.10) ◽  
pp. 225
Author(s):  
Gangadhar K ◽  
Venkata Ramana ◽  
Dasaradha Ramaiah ◽  
B. Rushi Kumar
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Volume Fraction ◽  
Slip Flow ◽  
Physical Parameters ◽  
Stretching Cylinder ◽  
Nanoparticle Volume Fraction ◽  
Fourier’S Law ◽  
Flux Model ◽  
Fourier's Law

This article represents a numerical investigation of heat transfer and slip flow of a nanofluid over a stretching cylinder in magnetic field. In order to explore the heat transfer characteristics Cattaneo-Christov flux model is utilized in place of Fourier’s law. By using, suitable transformations, the governing   partial differential equations are changed into non-linear ordinary differential equations.  A numerical method, known as, spectral relaxation method is used to solve these equations. By using pictorial graphs, the relevant physical parameters that appear in temperature and velocity distributions are analytically discussed.  Various types of nanoparticles like Alumina (Al2O3), Titanium oxide (TiO2), Copper (Cu) and Silver (Ag) with water as their base fluid has been assumed. It was identified that absolute value of skin friction coefficient and Nusselt number increases as each of nanoparticle volume fraction or Reynolds number increases. Temperature profile goes up in a faster way in Fourier’s law case than Cattaneo-Christov heat flux model. It is also found that the choice of copper (for large values of nanoparticle volume fraction) and alumina (for small nanoparticle volume fraction) leads to highest cooling performance in solving this problem. In order to examine the accuracy of the method, thorough comparison has been made with some previous results. 

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