The effective thermal conductivity enhancement of carbon fiber composites is investigated in this contribution using a three-dimensional numerical method. First a more realistic three-dimensional distribution of fibers dispersed in a matrix phase is reproduced by a developed random generation-growth method to eliminate the overrated inter-fiber contacts by the two-dimensional simulations. The e...

Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal st...

Thermal transport measurements have been performed on single-crystalline Co-doped BaFe2As2 down to 0.1 K and under magnetic fields up to 7 T. Significant peak anomalies are observed in both thermal conductivity and thermal Hall conductivity below Tc as an indication of the enhancement of the quasiparticle mean-free path. Moreover, we find a sizable residual T -linear term in thermal conductivit...

walled carbon nanotube inclusions Sivasankaran Harish, Kei Ishikawa, Shohei Chiashi, Junichiro Shiomi, Shigeo Maruyama Department of Mechanical Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. We report large contrasts in the thermal conductivity enhancement of phase change alkanes in liquid and solid state with single walled carbon nanotube (SWCNT) inclusion...

Different from the electrical conductivity of conductive composites, the thermal conductivity usually does not have distinctive percolation characteristics. Here we report that graphite suspensions show distinct behavior in the thermal conductivity at the electrical percolation threshold, including a sharp kink at the percolation threshold, below which thermal conductivity increases rapidly whi...

Group IIIA elements (B, Ga, In, and Tl) have been doped into PbSe for enhancement of thermoelectric properties. The electrical conductivity, Seebeck coefficient, and thermal conductivity were systematically studied. Room-temperature Hall measurements showed an effective increase in the electron concentration upon both Ga and In doping and the hole concentration upon Tl doping to ~7 × 10(19) cm(...

In this paper, we systematically investigate three different routes of synthesizing 2% Na-doped PbTe after melting the elements: (i) quenching followed by hot-pressing (QH), (ii) annealing followed by hot-pressing, and (iii) quenching and annealing followed by hot-pressing. We found that the thermoelectric figure of merit, zT, strongly depends on the synthesis condition and that its value can b...

Introduction Heat dissipation is the most critical problem that limits the performance, power, reliability and further miniaturization of microelectronics. The thermal performance of these devices is greatly affected by the thermal resistance associated with interface between the heat sink and heat source. The improvement of a thermal contact is associated with a decrease of the thermal resista...

We present an analysis of the dispersion characteristics and thermal conductivity performance of copper-based nanofluids. The copper nanoparticles were prepared using a chemical reduction methodology in the presence of a stabilizing surfactant, oleic acid or cetyl trimethylammonium bromide (CTAB). Nanofluids were prepared using water as the base fluid with copper nanoparticle concentrations of ...

The present paper discusses the various effects of parameters like particle volume fraction, particle material, particle size, particle shape, particle material and base fluid, temperature, effect of acidity(PH) on thermal conductivity of nanofluids. And also discusses the different mechanisms of heat transfer enhancement like improvement in the thermal conductivity, effect of Brownian motion, ...