scholarly journals Anomalous Increase in Specific Heat of Binary Molten Salt-Based Graphite Nanofluids for Thermal Energy Storage

2018 ◽  
Vol 8 (8) ◽  
pp. 1305 ◽  
Author(s):  
Hyun Kim ◽  
Byeongnam Jo
Keyword(s):  
Specific Heat ◽  
Molten Salt ◽  
Base Fluid ◽  
Solid Phase ◽  
Layer Structure ◽  
Synthesis Process ◽  
Nanoparticle Concentration ◽  
Anomalous Increase ◽  
Salt Mixtures ◽  
Graphite Nanoparticles

An anomalous increase of the specific heat was experimentally observed in molten salt nanofluids using a differential scanning calorimeter. Binary carbonate molten salt mixtures were used as a base fluid, and the base salts were doped with graphite nanoparticles. Specific heat measurements of the nanofluids were performed to examine the effects of the composition of two salts consisting of the base fluid. In addition, the effect of the nanoparticle concentration was investigated as the concentration of the graphite nanoparticles was varied from 0.025 to 1.0 wt %. Moreover, the dispersion homogeneity of the nanoparticles was explored by increasing amount of surfactant in the synthesis process of the molten salt nanofluids. The results showed that the specific heat of the nanofluid was enhanced by more than 30% in the liquid phase and by more than 36% in the solid phase at a nanoparticle concentration of 1 wt %. It was also observed that the concentration and the dispersion homogeneity of nanoparticles favorably affected the specific heat enhancement of the molten salt nanofluids. The dispersion status of graphite nanoparticles into the salt mixtures was visualized via scanning electron microscopy. The experimental results were explained according to the nanoparticle-induced compressed liquid layer structure of the molten salts.

Preparing high surface area porous carbon from biomass by carbonization in a molten salt medium

RSC Advances ◽  
2015 ◽  
Vol 5 (92) ◽  
pp. 75728-75734 ◽  
Author(s):  
Huishan Shang ◽  
Yanjie Lu ◽  
Feng Zhao ◽  
Cong Chao ◽  
Bing Zhang ◽  
...  
Keyword(s):  
Molten Salt ◽  
Surface Area ◽  
Porous Carbon ◽  
High Surface ◽  
High Surface Area ◽  
Molten Salt Synthesis ◽  
Synthesis Process ◽  
Salt Medium ◽  
Peanut Shells

Peanut shells were transformed into porous carbon with a high surface area through a simple ZnCl2-molten salt synthesis process.

Settling Characteristics of Alumina Nanoparticles in Ethanol-Water Mixtures

2013 ◽  
Vol 372 ◽  
pp. 143-148 ◽  
Author(s):  
Suhaib Umer Ilyas ◽  
Rajashekhar Pendyala ◽  
Narahari Marneni
Keyword(s):  
Heat Transfer ◽  
Base Fluid ◽  
Particle Diameter ◽  
Alumina Nanoparticles ◽  
Visualization Method ◽  
Nanoparticle Concentration ◽  
Enhanced Heat Transfer ◽  
Heat Transfer Fluids ◽  
Sedimentation Behavior ◽  
Settling Characteristics

Nanofluids are considered as promising heat transfer fluids due to enhanced heat transfer ability as compared to the base fluid alone. Knowledge of settling characteristics of nanofluids has great importance towards stability of nanosuspensions. Sedimentation behavior of Alumina nanoparticles due to gravity has been investigated using different proportions of ethanol-water binary mixtures. Nanoparticles of 40 nm and 50 nm are used in this investigation at 23°C. Sediment height with respect to time is measured by visualization method in batch sedimentation. The effect of sonication on the sedimentation behavior is also studied using ultrasonic agitator. The effect of particle diameter, nanoparticle concentration and ethanol-water proportion on sedimentation behavior of nanofluids has been investigated and discussed.

On the Electrochemical Thermodynamics of Minor Components in Molten Salt Mixtures

2021 ◽  
Vol 168 (2) ◽  
pp. 026502
Author(s):  
R. L. Fitzhugh ◽  
A. D. Clark ◽  
S. D. Nickerson ◽  
M. J. Memmott ◽  
J. N. Harb
Keyword(s):  
Molten Salt ◽  
Minor Components ◽  
Salt Mixtures ◽  
Electrochemical Thermodynamics

Numerical Simulation of Heat Transfer in Laminar Natural Convection of Mixed Newtonian-Non-Newtonian and Pure Non-Newtonian Nanofluids in a Square Enclosure

2021 ◽  
pp. 1-44
Author(s):  
Ajay Vallabh ◽  
P.S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Base Fluid ◽  
Volume Fraction ◽  
Numerical Study ◽  
Transfer Model ◽  
Nanoparticle Concentration ◽  
Left Wall ◽  
Square Enclosure ◽  
First Case

Abstract This paper presents a steady-state heat transfer model for the natural convection of mixed Newtonian-Non-Newtonian (Alumina-Water) and pure Non-Newtonian (Alumina-0.5 wt% Carboxymethyl Cellulose (CMC)/Water) nanofluids in a square enclosure with adiabatic horizontal walls and isothermal vertical walls, the left wall being hot and the right wall cold. In the first case the nanofluid changes its Newtonian character to Non-Newtonian past 2.78% volume fraction of the nanoparticles. In the second case the base fluid itself is Non-Newtonian and the nanofluid behaves as a pure Non-Newtonian fluid. The power-law viscosity model has been adopted for the non-Newtonian nanofluids. A finite-difference based numerical study with the Stream function-Vorticity-Temperature formulation has been carried out. The homogeneous flow model has been used for modelling the nanofluids. The present results have been extensively validated with earlier works. In Case I the results indicate that Alumina-Water nanofluid shows 4% enhancement in heat transfer at 2.78% nanoparticle concentration. Following that there is a sharp decline in heat transfer with respect to that in base fluid for nanoparticle volume fractions equal to and greater than 3%. In Case II Alumina-CMC/Water nanofluid shows 17% deterioration in heat transfer with respect to that in base fluid at 1.5% nanoparticle concentration. An enhancement in heat transfer is observed for increase in hot wall temperature at a fixed volume fraction of nanoparticles, for both types of nanofluid.

ChemInform Abstract: THE THERMAL EMF. OF ALKALI METAL-MOLTEN SALT MIXTURES

1977 ◽  
Vol 8 (48) ◽  
pp. no-no
Author(s):  
K. E. JOHNSON ◽  
S. J. SIME
Keyword(s):  
Alkali Metal ◽  
Molten Salt ◽  
Thermal Emf ◽  
Salt Mixtures

Comparative Study of Cooling Performance of Automobile Radiator Using Al2O3-Water and Carbon Nanotube-Water Nanofluid

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Sandesh S. Chougule ◽  
S. K. Sahu
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Base Fluid ◽  
Heat Transfer Performance ◽  
Pure Water ◽  
Transfer Performance ◽  
Nanoparticle Concentration ◽  
Cooling Performance ◽  
Forced Convective Heat Transfer ◽  
Better Than

In the present study, the forced convective heat transfer performance of two different nanofluids, namely, Al2O3-water and CNT-water has been studied experimentally in an automobile radiator. Four different concentrations of nanofluid in the range of 0.15–1 vol. % were prepared by the additions nanoparticles into the water as base fluid. The coolant flow rate is varied in the range of 2 l/min–5 l/min. Nanocoolants exhibit enormous change in the heat transfer compared with the pure water. The heat transfer performance of CNT-water nanofluid was found to be better than Al2O3-water nanocoolant. Furthermore, the Nusselt number is found to increase with the increase in the nanoparticle concentration and nanofluid velocity.

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