Managing heat is a major challenge to meet future demands for a sustainable use of our energy resources. This requires materials, which can be custom-designed to exhibit specific temperature-dependent thermal transport properties to become integrated into thermal switches, transistors, or diodes. Common crystalline and amorphous materials are not suitable, owing to their gradual changes of the ...

the present paper was aimed to study the effects of variable thermal conductivity and heat generation on the flow of a viscous incompressible electrically conducting fluid in the presence of a uniform transverse magnetic field, thermal radiation, porous medium, mass transfer, and variable free stream near a stagnation point on a non-conducting stretching sheet. equations of continuity, momentum...

in this paper, two-dimensional heat transfer in a semi-infinite wall with fins of rectangular profile has been investigated. the conduction equations of the wall and fins are solved simultaneously by a numerical method. the principal parameters of the problem are the fin spacing, length, and fin-to-wall conductivity ratio. in this investigation, the effect of these parameters on two-dimensional...

In the current research, thermal conductivity of magnetite (Fe3O4) has been calculated using molecular dynamic simulation. The rNEMD Molecular Dynamics Method provided in the LMMPS package is used for the simulation of the thermal conductivity. The effects of magnetite layer size and temperature on the thermal conductivity have been investigated. The numerical results have...

In the present paper, an experimental assessment was performed on the transient thermal performance of a heat sink filled by a phase change material (PCM) and PCM embedded with carbon nanofibers (CNFs) and titania (TiO2) nanoparticles as nanostructured materials. In order to enhance the thermal conductivity of PCM, CNFs and TiO2 nanoparticles at different loadings (0.5wt. % and 2 wt.% of CNFs a...

The macroscopic control of ubiquitous heat flow remains poorly explored due to the lack of a fundamental theoretical method. Here, by establishing temperature-dependent transformation thermotics for treating materials whose conductivity depends on temperature, we show analytical and simulation evidence for switchable thermal cloaking and a macroscopic thermal diode based on the cloaking. The la...

In the present paper, we present results of thermal conductivity measurements in commercially-available, chemical vapor deposition grown, heat-treated and non-heat-treated individual carbon nanofibers (CNFs). The thermal conductivity measurements are made using the T-type probe experimental configuration using a Wollaston wire probe inside a high resolution scanning electron microscope. The res...

Forced convection of heat in a two-dimensional channel, partially filled by a porous insert is considered. This system is assumed under fully developed conditions and constant wall heat flux. Further, the fluid and solid phases can feature internal heat generation (exothermicity) and consumption (endothermicity). Analytical solutions are developed for the solid and fluid temperature fields by a...

We consider a non-isothermal one-dimensional model of martensitic phase transitions that incorporates a finite bar with a non-monotone temperature-dependent stress–strain law and non-zero latent heat. Two dissipation mechanisms are considered: heat conduction and the internal viscous dissipation of kinetic origin. Time-dependent displacement and ambient temperature are prescribed at the ends of...